Thanks for your feedback. That’s what I initially do, I measured the voltages at the CB703 connector: -11.7(12), +11.7 (+12), +11.5(12), 5(5), 23.1(25) and -23.3(25). The problem doesn’t seem to be here. Moreover, I checked the voltages at D18 (SMD), that is going to pin 35 (IC21) and is exactly 1.2V, as in schematics. While I am not sure I will get to the bottom of this, your explanations are very helpful (I enjoy more learning something new, rather than having this repaired).
Hi mark I have a Yamaha RX-V396 5.1 channel receiver that previously had water damage to the main left channel. So I took out the shorted output transistors and driver transistors not sure if the drivers were bad but the outputs were shorted. The amp powered up and gave me sound out of the rear channels and the center channel. So to fix the main left channel I took working parts from the center channel to replace the Output transistors (Q216A/B) the driver transistors (Q201, Q203) the melted 330 ohm resistor (R214) and I also had to replace a blown 47uf 50V cap (C203). Also the .22x2 (R239) ohm resistors was open on one side so I replaced that also. There were also the 2 zener diodes (D221, D06) for the speaker protection relay that were bad so I also took that from the center channel as well. I also took the relay out of the center channel because I took away the protection diodes. Now the reason I did this is because I’m cheap and I want to know what parts I need to fix this channel before I order them. However it goes into high current shut down as soon as you push the power button display doesn’t even have time to turn on everything ohms out ok nothing is shorted even all the other channels ohm out ok. Any ideas I’m going crazy trying to figure this out. Thanks
+101computerman Got it working as it turns out even though the bias transistor whitch ohmed out ok in the blown channel when I took the heat sink off to change it I found it has split in 2 now it’s time to order replacement parts for the center channel
Thank you for your reply mark.I checked the mute drive circuit and one diode D12 reads 14v on both sides so i de soldered it on one side and the eq works fine now.maby a faulty cap or transistor.I'll keep checking.
Thnx mark for the reply. The technician guy had connected A TERMINAL rights posts to the right spkrs and left to the left speakers, same way he had done with the FRONT B and assigned as extra presence. I tried the B TERMINALS right & left to one speaker and done with the other spkr too. It sounds grt. But the front A TERMINALS doesn't give any sound output whn connected the same way.
The trick on these is to prepare a double ended POLARIZED AC cord; Take the receiver's own cord and plug it into one of it's own switched outlets. Take the double ended cord and run it from the the other switched outlet to the AC outlet or variac. The receiver will shut back down but the internal voltages will stay up. Make sure that the AC cords maintain the Neutral and Hot relationship, or BIG SPARKS will occur.
Hi Mark. I have a RX-v661 that goes in to protection mode. By the help of the service manual and your videos I have managed to narrow the problem down. The DIGA menu tells me that it's PS2 Low that is the course of the protection mode. Now I have measured all the PS2 voltages (+12, -12, +5V, +5D, +5I & +3.3D) and they are all fine except one :) When measuring the +12V at connector W100A I only get around 1.52V between pin 2(E) and pin11 (+12). I then measured the input to the +12v regulator (IC104) and that show +22V, so that seams okay. Now if I remove the cable that go from the MAIN2 board to the DSP board the output of IC104 increase to around 5 volts, but nowhere near the +12V that it's supposed to be. The IC104 don't get hot, and there are no signs of overheating in that area of the MAIN2 board Do you have any suggestions? Should I focus on the +12V regulator, and try and replace that, or is it more likely that the problem lies hidden somewhere else?
Very helpful (especially the trick with the double ended polarized AC cord - never heard of that before)! I don’t have a variac, but I’ll use the light bulb. You are right though; besides the fuse might have been blown by now, if it were an over-current issue. I will start measuring, but even if I am not able to figure out what’s going on, I still learned something. Thank you!
Update 3. Things changed. Now the bulb lights intensely (pulsating, rather) when connecting to AC outlet; in addition, power transistor Q716C (NPN) does not look good (when measured in circuit). Not sure if this is a new problem or, this was the issue all along. Question: if I remove the 2 power transistors from this channel, and restart the receiver, would that work? I want to check if the receiver starts without entering in protection, with that pair removed.
Update. Using the trick you mentioned before, I was able to take some measurements. I also used the light bulb as a precaution. It lights up a bit when connected to the power outlet for a second, and them dims out, so no over current issues, as predicted. The rear L power transistor Q716C (NPN) has 6.32 V at the base (should have been 0.4), 0 at source (OK) and 38.5 (40 on schematics) at collector...continued
So I have this same receiver, rx-v661 which works fine, however the display no longer works. Tech seemed to think it was a problem with the power supply. Any ideas on that? If so do you know where I could get the parts to replace and fix it? Great video by the way
Yeah your right about that,I went to turn on the amp and i heard a loud snap and flash..I thought the transformer went,but it was the circuit lifting up from the board soldered it tested it same thing so i put a jumper on it.the yamaha RX-V2500's fan circuit is still not working so i improvised it with it's own power supply Until i can order a new board.I know yes i am an amateur,but thank you for your informative video's.
Hi... I have this receiver. I haven't used it for the last few years due to house reno.... Today I hooked it back up today and was listening to it for about 45 mins. When I moved the receiver into the stand the front speakers and the rear speakers stopped working..... the center channel and sub are still working. I've been thinking I pushed a button or something..... Now 2 hours later and I've tried every setting.... I'm guessing this might be internal.... any thoughts?
Sorry didn't reply sooner. Don't have any Kenwood service data. Blue flashing in the relay sound like a serious short in there somewhere. This could involve working around some hazardous AC voltages. If you are comfortable doing so, unload the transformer secondary and see if the clicking / flashing continue. Also, if it blew the fuse, DO NOT replace it with a higher value or tinfoil it.
Thanks Mark. the US part may not work as it is not calibrated to 230-250V AC . I did google but could not find any supplier stocking the part. Will fetch it from the service center and try if removing the rust help. Otherwise, i dont see much options because I dont of anyone here who can work at the component level.
If the bias transistor is bad I would recommend ordering the Yamaha part number, VK432900. You might be able to get away with a 2SC2603, but the problem is the bias would probably be somewhat at variance with the other channels, and there is no real adjustment provided.
Hello, I have a kenwood GE7030 equalizer Thats being a real pain.I have the service manual and ive checked all spots for proper voltage and they seem fine.Before it started to go it would sound like distortion on both channels,It would do this off and on untill it died.the display works fine but no sound and the bands display nothing.It also powers on and off with no problems.On the amp board i replaced 3 high speed diodes that looked like thay have gotten pretty hot but still nothing.
hi john it was capacitor that blew up completely did not see it before there is one more cap i don't know if its thermal paste on it or leaking mind you i got these receiver on ebay and it look like it was brand new no dust the fan and the capacitor fix so far must have been a lemon i don't know how to post pictures on youtube but i took some of the blown capacitor and board
Hi Mark, My Yamaha RXV661 which was running fine for the last 4 years suddently refused to turn on. I was trying to plug and unplug a few devices from the same power plug when I found the 2 of the SCENE button LED turn on for a while. Thereafter, the device simply refuses to turn on. Checked the fuse out of common sense, but they seem ok. What could have gone wrong. Will appreciate your inputs Mark.
Hi Mark, My knowledge of electronics is very basic. I have a Yamaha RX-V773. Failed while watching TV - while at normal volume... The red power LED glows dim, no other display visible. Press the on/off button on the remote, the red led flashes dim. The fuse "was" OK, until I tried to do the factory reset to default. As soon as I pressed the button combination on the front panel to attempt the factory reset, there was a big flash as the fuse "went open circuit". With the fuse open circuit and using a couple of different control panel button combinations, the front panel does light up with text and numbers... This proves the front panel still works - but I think that's it - probably nothing useful in the display I do not know if a test I performed proves anything, but connecting my multi meter (set to ohms) across the speaker output connections gives a resistance reading on all channels EXCEPT centre, left surround and right surround. So, that is 3 speaker connections adjacent each other that look bad to me (unless this test is useless of course). Some history - which may have been the beginning of the failure, some months ago, the centre channel started to cut-in and out... I thought the amp was history so I went out and bought a Denon. While performing the unit change over, I found that one of the centre channel speaker wires had come out of the connector =:-( .... Anyway, the Yamaha still worked after re-connection the speaker wire, so I installed it at my holiday house where it worked fine for some weeks, until it failed a few weeks ago while watching TV.... Sorry, not much info, but on this brief description, what is your feeling - trash it or do you think it is worth fixing. Is my output test valid? Thanks Mark, Jim (in AUS)
If it blows the main fuse something is seriously shorted. Yamaha's protection circuits work so fast in the event of a current overload, they usually cut off before a fuse can even blow. Anyway, forget about checking resistance at the speaker terminals for now. Check resistance emitter to collector of the output transistors, focusing first on the channel you were having problems with. If there's no particular issues found there, check for a short from the collector of any NPN output transistor to chassis ground; do the same for any one of the PNP outputs. (each channel's NPN collectors are tied together inside, so are the PNP's) Occasionally there is a bad mica insulator. If this is the case the can also be a carbon path formed from that screw hole in the heat sink, right up through the body of the transistor. In this case the transistor must be replaced along with the mica. Merely trying to clean away the carbon as a fix will not hold - I been stung on that one before.
I had another Yamaha a couple days ago with a similar symptom. One of the main filter capacitors was shorted . Fuse blown - measured dead short from the collectors of (PNP or NPN - I forget which) output transistors to ground.
G'day Mark, thanks for the update. Just wondering if you might be able to point me in the right direction to download a wiring diagram for my RX-V773.... Been searching but not having much luck. Thanks, Jim jim.stapenell@gmail. com
G'day Mark, I did reply to your email address - did you receive my message?..... As it happens, I found a manual online for an RX-V673 which I think is similar to my RX-V773... Anyway, I wonder if you might be able to comment on something I found. My relay does NOT click when the power button is pressed. I unscrewed the board with the relay - fitted clip leads between the ground points on the board and the unit metal frame. I then switched on the power, applied multi meter to measure the voltage between the closely grouped 5v and ground (?) at the 11 pin plug connector - I measured the voltage OK, but when the multi meter leads contacted the 5v & Ground points, the relay clicked. From this info, can you possibly identify any obvious faulty components - or at least group of parts I could replace as a test. I know this request is a long shot but thought I would ask anyway. The reason the relay clicked when I connected the multi meter is probably because I had the board disconnected from the 11 pin plug? Who knows.... Let me know if you did get my email... Thanks Mark, Jim
the unit work perfectly, if i wait some seconds between power on/standby operaton. if this is a normal operation, i'll go close the cover of the unit. Thanks for your help, and before i forget, nice videos (but a little dangerous for curious people) you posted. Sorry about any errors in text. see ya.
Thanks mdzacharias i open my receiver and fixed a broke fan and change two fuse thant blown going to try your advice two questions though when i unplug the hdmi board the receiver does not shut off clicks on and then off over and over but the power does not blow is it possible its bad caps on hdmi boards like the other onkyo's. One more question i have seen your reviews of the multimeters can you recommend a good starter meter on the cheaper side that can handle voltages of a audio receiver
No, it doesn't. I also visited the local yamaha service center and they said that the DSP PCB has got rusted for whatever reasons. Also gave the faulty PCB part no WJ698200 which needs to be replaced. Now, this PCB is not available in India. Can you suggest where should I get this from.
I think you need to look at the PRV line on the Main (2) board. It's the board along the top of the heat sink, so you should be able to get to stuff pretty easy. The PRV line sums all the power supply lines and provides an error voltage for the microprocessor. This winds up over at IC21 pin 35. Occasionally the backup capacitor C103 might leak and give false trigger on the micro but usually just a bad regulator over on Main (2).
I found the can that blew off the cap down in the receiver and it reads 16v4uf. They didn't have that at radio shack. Will a more common one do? The cap was in that assembly that screws to the heat sink above the stuff you are working on and has two 5 or 6 lead cables coming off it. Also wondering what soldering iron and vac you are using. Thanks, Scott
Scott Young You can solder in a 4.7uF at 16 or 25 volts. Cut the leads fairly short and first solder the original circuit board pads a little, then tin the capacitor leads with solder. You should be able to use the soldering iron to then solder the leads to the board. Be sure to observe polarity of the cap. The old solder station was a junk MCM model and it died. I went back to using my old Weller station. The other device you may have seen is a Denon Instruments desoldering tool. I don't use it much anymore; a friend gave me a hot-air gun with a pinpoint nozzle attachment. Don't know the brand.
Thanks going to try to check those things hopefully but the receiver stays on when i turn it up but past 44 - 45 the sound cuts off not the receiver but im guessing its the same problem
It's the cooling fan,on Power(5) PCB it puts out upto 21 volts. when i reconnect the fan it goes into protect ( the fan circuit that is) and then won't work..I bought the receiver on ebay for $20, the Main(1) PCB was damaged from being dropped on the speaker outputs .The board circuit lines were cracked and i have repaired it jumper wires and works fine now. self diag shows all normal.I didn't want to fully disassemble the whole thing Luckily the troublesome fan circuit is easy access.
I have a Harman Kardon AVR 354 receiver I repaired (replaced L7915) that worked very nice. I didn’t use it for a few months, and then when I plugged it in and turned on, acted strangely. The unit’s front panel lighted up completely (all characters were on). After reset, it functioned “normal” but with repeated (every minute or so) sound dropouts (short, 1s or so). Strangely, during the sound dropouts the front panel blacks out, as if the unit loses power (the power on led is on though), but then comes back and functions well for a little while. In the end (~10 minutes) the sound drops off completely (but the unit stays on, and the front panel working OK), or turns into a whistle. This happens in all sound modes, all inputs, with or without any external connections (even with no speakers - reacts the same, you can tell that from the front panel blackout). Between the sound/display dropouts it functions completely “normal”. I tried repeated resets, doesn’t change anything. The F110, F111 fuses and wire (jumper) from HDMI board to Regulator board upgrades have been addressed by the previous owner. I didn’t see anything similar on Internet, have you encountered this issue before?
Not sure if you meant to say you had already disconnected the collectors from the heatsink. Anyway, don't ignore the bias transistors, they don't fail often but can take out the output transistors in a hurry.
Great video posts, Mark. I have an RX-V667 that is tripping circuit protection on DC after a lightening strike. All values in the diagnostic menu are normal except for P1-1 (DC_PRT on IC902) showing value 0 instead of normal 32 to 74. Is there a place to start before looking at each amp channel?
***** Start the receiver in protection cancel mode and see if there is a DC offset on one or more channels. DC on one channels obviously means that channels needs repair. More than one is a power supply problem of some sort, or there could be a problem involving Q1072 (not) providing a -12.6 volt bias to all amp channels.
Great video, My yamaha RX- V640 shutdown right after i press power button.I hear a click then the screen comes on and it goes back off.After it shuts down i see DC offset on the emitter resistors.What are should i check for that kind of behavior?
I have a Yamaha htr 5440 receiver and no channels were blown blown channels are usually caused by wiring your speakers at too low of an impedance like if the impedance is lower than what the receiver is able to handle
@killerkoop33 I cannot find this model number listed. Not a U.S. model anyway. This could take some real troubleshooting. Are you a technician? The likelihood is either a bad main power transformer or a high-current shutdown, such as might be caused by a blown amp channel.
Thanks for your reply. Assuming that there are some faulty and shorted circuits already, and since voltages are maintained, does that mean that the risk to fry/damage (even more) some components is increased, due to longer exposure to high current?
I am bit familiar with electronics. I checked all C4468 and A1695 transistors with DMM, could not find any shorted ones. I have not checked at resistors and diode yet.
You can use 2SC4027 and 2SA1552. Be careful - they are reverse basing from the originals. You can even use 2SC4793 and 2SA1837, but they are much larger TO-220 package.
Hello Mr. Mark I have a Yamaha rxv459, who hand lights up and running (i listen radio to MD/OUT in other amplifier), but is not output to any audio channel. You can help with;
Assuming the power supply voltages to the HDMI board are OK, if the HDMI indicator on the front panel still lights up on an HDMI source, then probably IC1 is bad on the HDMI board. If the indicator does not light, then likely IC14 is bad. The nomenclature in the service manual appears to misstate which IC is the transmitter and which is the receiver.
Hi Mark, Yamaha RX-V795a. Shuts off after 0.5 sec. Diagnostic mode quickly (0.5s) shows: "PS PRT 39%". Output transistors (C3856 / A1492 pairs) look OK in circuit. The Noble resistors look OK. The regulator 7812 (x2), 7912 and 7805 (all on the main heatsink) have the proper voltage. Mind you, I only have 0.5 sec to do the measurements. Is there any way to increase this time? I can’t measure the DC offset, too short a time.
Actually used a "octopus" or "curve tracer". You can Google Octopus component tester. for info. A diode check on a regular multimeter also works fine. A leaky diode like the one in the video measures low both ways.
The big resistor you see is 750 ohms. It's good when the voltages to be bled are over 20 volts. Less than 20 volts I'll often use an 8 ohm 20 watt resistor - they're common around my shop.
i have a yamaha rx v1900 av receiver,both right and left channels were shorted out destroying four power transistors,four driver transistors,two 5.1v zener diodes,two 220 ohms resistors,also one of the power supplies were damaged that supply the main amp board with a dual plus and minus 61 volts,this has been repaired but the main amp board is dragging the dual supply down very low,i cannot find any more shorts on the main amp board that may be causing this problem,can you please advise me.
C3856 tested bad after all, but I am not sure that this was the original problem. If that was the case, why would have the receiver in diagnostic mode, tested a PS PRT voltage issue? Maybe this developed afterwards. Anyway, I will stick to the original plan (to replace both the power and driver transistors for that channel), and I will let you know... in a month!
Have the same receiver - and I think a lightning surge took out my HDMI circuits. It turns on, but seems like no signal is coming out of either channel. Do you know what it would take to fix this?
My guess is that it would work but maybe be more NTSC than PAL for example. HDMI codecs and permissions are way over my head. Internal voltages would be compatible, but even with that I'm not sure it would work. I would suggest another used 661 might be a better option, maybe a broken one with other problems.
@mdzacharias It's not an integrated amp,it's a power amp Sony TA-N80ES.I've heard that this is common for this power amp.of course it was the end of a lot of them :( So the fans won't "hurt" the transistors in any way.Thank you
I got that last part in fixed that but my sound still cuts out at about 45 or so and was able to stay on for a few seconds at a higher volume i am not sure seems like something with the front cover because it did stay on at almost max volume. But it still says check speaker wire for the first 10 seconds when i first power on the unit after plugging it in to the wall for the first time.
Thanks! Yes, HDMI indicator did light up when it got the signal (when i used the selector). So that is good to know. Any idea how much say IC1 should cost, or in general, to repair something like that? (Not that I want to replace it myself - a cap or a resistor, I can handle. Not a chip).
Yes but there would have to be some appropriate resistance in the setup to limit the current plot on the scope screen. The curve tracer produces a VI plot of voltage versus current on the scope screen. Search for "oscilloscope component tester" on youtube, should show how it works.
@costellom5 Also if yours gets hot that is a warning sign. Lots of people overwork these things. They can and will blow up if you run them too hard for too long. I suppose the fans are a good idea.
goodmorning, mark, i have a yamaha rxv 661 and sometime ago i was playing a CD i had just gotten whilst i was in the yard. unknown to me the CD was recorded high and so when i heard the volume came up i ran to lower it but was too l8t. the reciever just shut down n i waited a few minutes then turned back on i saw the display but shortly after the power just went back off i tried it again this time all i heard was TWO CLICKS. what do u think is my problem and can it be fixed?
Hello mark i have a rx v373 with Dc prt 255 hi error can you please guide me where to start checking for faulty components. I know this video has been uploaded from 8 years but hope you still can help me thank you in advance
Hi mdzacharias, I have got RX-V630 which turns on for a brief moment and shuts down. Sometimes there is message check SP wire on start. I have disconnected all my speakers but still the problem remains. Can you guide me on where the problem would be or have you got a circuit diagram for it?
i have a kenwood that was turning its self on and off but would still work now it wont come on the main relay clicks rapidly and has blue flash in it you think it could be the transistors?
Hay mark i was able to get the receiver to turn on loosing the front cover it turned i turned up the volume it stayed on with no speakers attached and then i put the back and front cover on it would not work loosened the front and got it to turn on5 seconds later a power transistor blew the part number is SK C4468 i only found them on ebay in like china any were you know of in america were i can get them sooner
Nice work, I have a yamaha rx-v667 and it works great but i have trouble getting radio stations to come in. after looking it over i see the antenna plug is bent up kind of funny and I'm thinking this might be a bad connection. would this be easy to fix? Should I take it to a shop? I have done some soldering before but wanted to ask. thank you.
dankbobby The tuner is a complete module and fairly easy top replace except it is situated kind of underneath the HDMI board. The part number is WQ756600. List price is about 40.00
Mark, I have a RXV-665 that has the STK443-130 amps....The unit had a similar problem,shutdown and I can get the self diagnostic to read - DC PRT :075H Do you have any experience or tips on this model,,? Thanks, Steve
@killerkoop33 The power transformer usually only goes out if you've been running it really hard for a couple hours.The transformer can be checked by a knowledgeable person. Also Yamaha with a blown channel may pull so much current at turn-on that the protect is triggered instantly, you never even see the display come on. If the transformer is OK this is probably the case. I wouldn't recommend just ordering the transformer til you know it's bad. About 135.00+frt. US model.
Hi Mark, I have a Yamaha RXV 661 Receiver and the Polk Rtia 3 connected to it via the front A and front B/ zone 2 with extra SP assign mode. It only plays the LEFT SPKRS woofer & RIGHT SPKRS tweeter. Can u pls throw light on the issue as I am not able to know work it out.
Hi Mark, I have a RX V477 working on, its brand new, got off Ebay, in protect mode. Got into the diagnostic mode, first of all I don't understand what all that stuff means in diagnostic mode, so far I pulled and replaced all the output transistors, I had already bought all 10 anyway, but the old ones checked fine as did the emitter resistors, I'm new to electronics, went to school and trying out a few of these bad stereos to get some experience. What I need is a schematic of the power amp section, can't find it for purchase or free. And something about how the fault mode codes work. Apparently I have some other bad items in there I failed to check. BTW in fault mode I seem to have one dead front channel. Good learning experience!! Thanks for the help. Subscribed!!
+Vernon Bosshard This vid cleared up a lot of confusion, so much crap on the net about why units go into protect mode, but from what I read is its always due to DC offset on the power transistors or something to do with the power amp section causing a fault. I bought a few units off Ebay for practice, got a Sony and found the schematic online. What size resistor do you use as a Cap bleed off?
+Vernon Bosshard I often use a 750 ohm 20 watt resistor to bleed of the higher voltages, especially if the voltage on a particular unit doesn't bleed off by itself. Lower voltages sometimes I'll use a larger eight ohm resistor because it bleeds off faster.
I do not know what "coil" you are talking about. The primary of the main power transformer would read much less I would think, and still be OK. If you measure OHMS at CB155 on the Operation 3 board (standby power board) and it reads low, the main transformer is ok. At this point you probably have a blown (shorted) amplifier IC. These are somewhat expensive and mostly only available from Yamaha.
hello, i'm a technician from Brasil, and i had some troubles with the receiver that i already repair, the unit fails to turn on if i press the power button right after set the unit to stand by, i have to wait 5 seconds before turn on the unit again, i already repair the (-bv and -bi) lines, after the unit is on, al voltages and protection circuits are normal, do you have any idea to fix this issue, the unit is a Receiver Yamaha RX-V730.
never mind it was a capacitor that blew im blind i fixed it does not look like anything else is bad i need a multimeter i would post a picture not sure how it is the board in front of the amp like your fixing in the video it has the output transistors im not sure but im guessing the Channel with the capacitor that blew up amp channel with problem
hi i had a question how would i fix my ir sensor on my harman kardon avr 40 i bought a new remote for it but the receiver isnt working with the remote and the remote works good.
ive not bolted back the main amp board to the heatsink and ive disconnected the thick power wires from the collectors of the power transistors cause ive already had 4 more power and driver transistors go short on me cause of a fault with the plus and minus 61 volt driver supplies,there seems to be something on the main amp board causing the dual supply to be very low,im having to run the amp in diagnostic mode so i can test but i dont know what else to do and yamaha uk are very unhelpful.
Nice video! I have one of these that just came in our store and the owner said they were listening to it LOUD and it went off and now when you hit the power button there is nothing. Any ideas? Think it is fixable?
You may have damaged some of your new parts, but I would look at possibly damaged or missing mica (or rubber) insulators.for the outputs. Could be a collector is shorted to the heatsink.
This is actually a very common problem with these. Are you a technician? The bad parts are on the main board, kind of hard to get to. Everything has to come out and parts soldered in from underneath.
Hey mark love thank you for this video I have the exact issue with my v661 I have done changed the output transistors but am struggling with the other repairs like the driver transistor I need assistance with the range it should read when tested normally and furthermore. I would like to if possible repair as I would hate to see it end as land fill. Any help would be grateful.
+Andrew Shorter If the outputs were bad ASSUME the drivers are bad, also the 5.1 volt zener diode. Also check the resistor between the emitters of the driver transistors. After these parts replaced, check resistance from base to base of the output transistors and compare to other channels(s).
Well, a variac would be nice. You could put a 100 watt light bulb in place of the main fuse. If it glows bright, there's an over-current situation. This really seems more like a power supply thing though, and the PS PRT error code backs me up on that.
Mark, I have a Yamaha RX-V2090 that I bought new (for $1549!) somewhere around 1996. It has been a great unit, but over the years has lost some of the channels for the speaker outputs. I have downloaded the service manual, I opened up the case tonight, and am looking for obvious signs, like discolored boards, but am not quite sure where to begin testing. Any advice on where to start? Thank you!
Mark Zacharias Thanks for the reply. I have figured out how to get it in diagnostic mode, but it seems some of my buttons are sticking. For example, if I push "Tape 1", the "Tape 2 Monitor" comes up. It seems a few of the buttons are mixed up with the one next to it. I do have the remote, but has the same issues. I'm not too surprised for an 18 year old unit. What can I use to clean them up with? Can I contact you off of youtube? I may have a lot of questions, if you are willing to help... Thanks!
I was able to take the remote apart and clean it. It appeared someone (besides me) poured a few cans of Pepsi inside. I just (carefully) used soap and water to clean the contact side and the button 'sheet'. It has never looked so good! Would something like rubbing alcohol also have worked on this, and/or the receiver?
You have serious problems now - the amp channel is blown like in the video. The transistor number is abbreviated. The number is 2SC4468 and it's complement is 2SA1695. The drivers are also blown, probably also the 5.1 volt zener diode, maybe some other parts.
Probably either the remote receiver itself is bad (it happens) or maybe there are bad solder connections there at the IR receiver module. This also is pretty common. Way down the list would be some other fault in that area, a circuit board flaw, leaky cap, bad microprocessor, etc.
Wierd i was able to get audio when turning it on just now but when i pluged in the fm antenna it shut back off. There is a fan inside that is not working does that cause the receiver to power off like that its 120mm fan was going to replace it
Ok, I can't quit. So I checked the noble resistor and it is bad. I going to replace those two transistors also 'cause they are so cheap and apparently go bad. But can you say how to mimic that noble dual emitter with p/n mcm 28-0520 (since that part not available)?
Scott Young You might want to double check that resistor - they rarely go bad on the Yamaha's. If the outputs are bad I guarantee the drivers are bad, and probably the 5.1volt zener diode as well. Also the 100 ohm resistor that sits between the emitters of the drivers should be checked. I haven't seen dual .22 ohm 5 watt resistors on eBay. If it's really bad, usually only 1/2 is bad and the other half could be bypassed with a single. If you're in the U.S. B&D Enterprises would have the dual, I'm sure. I have a drawer full of the things at work. They're really common if you work on these things. Many of those I have are pulled from scrappers.
I would definitely be looking at the power supplies, like plus and minus 15 volt (maybe + or - 12 volt) lines, also any muting circuit that may be used.
Mark great videos you inspirated to me to fix my first receiver it an ONKYO HT-RC360 and it has issue like sidsasi described. The receiver has a clicking sound when powered on. It show a quick message saying check speaker wire before it turns off. The display only shows the message for about half a second before powering off. Im hopeing its bad capacitor all i know how to fix lol thanks for videos
Well i am but out of money on this puppy i tested with the meter and found 3 more bad transistors 2 sk1695 and 1 more stc4468 now i thought it was fixed put it back together and it says check speaker wire one the first power up on the second it stays on. I thought i just had to hook speakers up tried that but when i put like fm radio on when the speakers are about to show it clicks off.
Update2. I tracked the high voltage, back to transistor Q708 (NPN, C2240). I replaced it, and now the readings at the Q716C (NPN power transistor RL) are much closer to the schematics: the transistor base reading changed from 6.2 V to 0.47 (0.4 on schematics). Unfortunately the symptoms are identical, and the display still shows the same PS PRT 39%. Other voltages are OK, no DC offset… I wonder if I can reset the unit, but how, since the display is gone in 0.5 sec. I guess I am stuck.
@ mark zacharias .Do you repair these receivers for the public. I have a Yamaha RX-v665 that I believe may have been damaged from a lightning surge. Having trouble trying to find someone near me who can repair it.
I'm not really wanting to deal with shipping and receiving and all that; and besides, lightning can be pretty devastating, often unrepairable. What is the receiver doing wrong? And are you sure it was lightning?
@costellom5 You mean the desoldering braid? Pretty common in my work. I also was using a spring loaded solder removal pump, if I recall. I don't use that so much these days - too easy to mess up the solder pads.
Hi, i have an amplifier which hv the label on the motherboard for the capacitor to be 2200uF 35V. However, the manufacture put 1000uF 35V caps in it. can i replace it wh the 2200uF 35V caps instead according to the board?
Just curious if you've run into the same issue with a rx-v795a Yamaha and if it could possibly be the same fix? Seems like every blog I've read says something different. Relay clicks but no power. Thanks and good work!
+Justin Bergendahl The most common thing is a blown amp channel caused by bad solder connections at the bias transistors. I would check continuity of the main power transformer first. If the unit went out after playing too loud for too long, the transformer could be bad. You need some skills like soldering and know how to use a multimeter or you're probably out of your depth on this one.
+Mark Zacharias well I changed the relay on the main power thinking it was the problem but still getting the issue. Main transformer has 120v. The aux outlets work without power on. It has to be within the amp or a capacitor dried out. You obviously deal with these a lot. Just trying to narrow it down. All help is much appreciated
+Justin Bergendahl You should check continuity or the primary winding of the main power transformer.Should read a very low DC resistance. UNPLUG from the wall first! Next check for emitter-collector shorts on the output transistors. The smaller amp board amp channel nearest the rear of the unit is most common.
In the diagnosis mode of Yamaha htr 6030 a message for a very short time "PVR PRT 59"is displayed and the receiver shuts down. What does it mean and where does the fault lie? It definitely means power supply issue but what does the number 59 signify ?
Indicates a power supply problem. There is a Protection Cancel mode that will allow you to keep the unit ON while you troubleshoot. email me at mark_zacharias@sbcglobal.net and I can email you the service manual. Most likely a bad voltage regulator IC like a 7812, 7912, etc.
Hi Mark. I have been looking though your videos seeing if you have encountered my problem. I have a Yamaha RX-V667 receiver. It was working fine until recently it started constantly switching DSP modes. Its happening intermittently. I some of the other buttons on the front are also activating. Is it possible just to replace the front panel? Where could the replacement part be ordered?
pvdeluca Kind of unusual problem. The front panel switches are part of a couple of resistive networks. Any leakage could trigger this. Like if some liquid got in there somehow, maybe causing some corrosion. Tact switches can also be leaky but this is less likely. The part number for the front board is WU427500 for the U.S. model only. Ending in 600 or 700 for other markets. Probably fairly expensive.
Mark Zacharias Hey thanks for the response. Ive googed for days to find someone with the same problem. My apartment is very humid so this might have caused the issue. Too bad it was a great amp. It would feel like such a waste if i didn't get this repaired.
Yes it stays on and can get audio but it shuts off when i turn it up pass 40 thats about half way that would be just like if i speaker wire cross but i don't still inside the receiver then back to the drawing board people
Mark, great video! I have a BA in EE but haven't really used anything I learned since I got my new job. I have a Yamaha Rx-v765 that I believe is in high current shut down mode like the one in this video. When I plug it in I hear 3 clicks from the 3 relays but there is no display. I have checked voltage going to the display and it measures close to what the service manual says it should have. Do you happen to have any tips or tricks to verify it is in high current shut down mode or any other tips on where to begin troubleshooting? Part of me says I should just send it in for repair but my inner nerd is telling me I should be able to fix it myself.
These can have a variety of problems. If the main power supply voltages to the output transistors is staying on, then probably not a high current shutdown. Maybe the display circuit - maybe a blown channel. I would start by looking for any shorted output transistors. I can probably send you a pdf of the service manual.
Mark Zacharias I have the service manual but everything I have checked so far seems to be correct. I haven't dug to deep into yet though. I basically just checked a few things I could easily get to like transformer and display board voltage. I was only using the rear speaker outputs at the time it went out as my main speakers are powered. I should also note there is about 56 volts going to the chassis. I will check the output transistors next. I appreciate the reply.
Mark Zacharias None of the output transistors appear to be shorted as far as I can tell. They all have high resistance across collector and emitter. I'm not saying my in circuit transistor testing is 100% percent accurate either though. I may do some more exploring in the display circuit.
Mark, I think I may have found an issue. There is a 25 pin ribbon cable that goes from the main video board to the display circuit. When analyzing the voltages coming out of the video board to the ribbon cable there are several discrepancies. Pin 24 which is labeled 3.3DSP is supposed to be 3.4 but I am reading only 1v. Is that just because of another problem and the microprocessor is telling the display not to turn on or could the processor itself be damaged. I think I maybe getting in over my head here but it is certainly fun. Sorry for hijacking your video.
Jeremy Meyer I have seen things like this cause a "no display" problem. In my case. I replace the digital board, where the 3.3D (for display) is generated. (Seen this twice only)
Hi mark i actually found a part on a board that exploded its not a capacitor or a transistor but is on the same board output transistors you told me to check i put the part number in google and some part site no luck it says C5443 little black think with one flat side one curved i post a picture if i could any help would be greatly appreciated
![[Naprawy] Yamaha RX-V661 (po prostej(?) naprawie)](/img/1.gif)
Thanks for your feedback. That’s what I initially do, I measured the voltages at the CB703 connector: -11.7(12), +11.7 (+12), +11.5(12), 5(5), 23.1(25) and -23.3(25). The problem doesn’t seem to be here. Moreover, I checked the voltages at D18 (SMD), that is going to pin 35 (IC21) and is exactly 1.2V, as in schematics. While I am not sure I will get to the bottom of this, your explanations are very helpful (I enjoy more learning something new, rather than having this repaired).
Great work! I really enjoy your smooth and calm presentation.
Hi mark I have a Yamaha RX-V396 5.1 channel receiver that previously had water damage to the main left channel. So I took out the shorted output transistors and driver transistors not sure if the drivers were bad but the outputs were shorted. The amp powered up and gave me sound out of the rear channels and the center channel. So to fix the main left channel I took working parts from the center channel to replace the Output transistors (Q216A/B) the driver transistors (Q201, Q203) the melted 330 ohm resistor (R214) and I also had to replace a blown 47uf 50V cap (C203). Also the .22x2 (R239) ohm resistors was open on one side so I replaced that also. There were also the 2 zener diodes (D221, D06) for the speaker protection relay that were bad so I also took that from the center channel as well. I also took the relay out of the center channel because I took away the protection diodes. Now the reason I did this is because I’m cheap and I want to know what parts I need to fix this channel before I order them. However it goes into high current shut down as soon as you push the power button display doesn’t even have time to turn on everything ohms out ok nothing is shorted even all the other channels ohm out ok. Any ideas I’m going crazy trying to figure this out. Thanks
+101computerman
Got it working as it turns out even though the bias
transistor whitch ohmed out ok in the blown channel when I took the heat sink off to change it I found it has split in 2 now it’s time to order replacement parts
for the center channel
Yamaha is just about my favorite. I work on so many because I do factory authorized service and people ship them to me from about a four state area.
Thank you for your reply mark.I checked the mute drive circuit and one diode D12 reads 14v on both sides so i de soldered it on one side and the eq works fine now.maby a faulty cap or transistor.I'll keep checking.
Thnx mark for the reply.
The technician guy had connected A TERMINAL rights posts to the right spkrs and left to the left speakers, same way he had done with the FRONT B and assigned as extra presence.
I tried the B TERMINALS right & left to one speaker and done with the other spkr too. It sounds grt. But the front A TERMINALS doesn't give any sound output whn connected the same way.
A and B should sound the same since they run from the same internal amplifiers. Surround, Center, etc are different internal amps.
@@mdzacharias something's s miss. Have called the technician. Let's c, will update once done.
The trick on these is to prepare a double ended POLARIZED AC cord; Take the receiver's own cord and plug it into one of it's own switched outlets. Take the double ended cord and run it from the the other switched outlet to the AC outlet or variac. The receiver will shut back down but the internal voltages will stay up. Make sure that the AC cords maintain the Neutral and Hot relationship, or BIG SPARKS will occur.
Hi wanna know if you provide repairs for the public i have a dead harman kardon 3700 with no power no stand by light
Hi Mark.
I have a RX-v661 that goes in to protection mode.
By the help of the service manual and your videos I have managed to narrow the problem down.
The DIGA menu tells me that it's PS2 Low that is the course of the protection mode. Now I have measured all the PS2 voltages (+12, -12, +5V, +5D, +5I & +3.3D) and they are all fine except one :)
When measuring the +12V at connector W100A I only get around 1.52V between pin 2(E) and pin11 (+12).
I then measured the input to the +12v regulator (IC104) and that show +22V, so that seams okay.
Now if I remove the cable that go from the MAIN2 board to the DSP board the output of IC104 increase to around 5 volts, but nowhere near the +12V that it's supposed to be.
The IC104 don't get hot, and there are no signs of overheating in that area of the MAIN2 board
Do you have any suggestions? Should I focus on the +12V regulator, and try and replace that, or is it more likely that the problem lies hidden somewhere else?
Yeah - replace the +12 volt regulator and you should be fine. Good job!
Very helpful (especially the trick with the double ended polarized AC cord - never heard of that before)! I don’t have a variac, but I’ll use the light bulb. You are right though; besides the fuse might have been blown by now, if it were an over-current issue. I will start measuring, but even if I am not able to figure out what’s going on, I still learned something. Thank you!
Update 3. Things changed. Now the bulb lights intensely (pulsating, rather) when connecting to AC outlet; in addition, power transistor Q716C (NPN) does not look good (when measured in circuit). Not sure if this is a new problem or, this was the issue all along. Question: if I remove the 2 power transistors from this channel, and restart the receiver, would that work? I want to check if the receiver starts without entering in protection, with that pair removed.
Update. Using the trick you mentioned before, I was able to take some measurements. I also used the light bulb as a precaution. It lights up a bit when connected to the power outlet for a second, and them dims out, so no over current issues, as predicted. The rear L power transistor Q716C (NPN) has 6.32 V at the base (should have been 0.4), 0 at source (OK) and 38.5 (40 on schematics) at collector...continued
So I have this same receiver, rx-v661 which works fine, however the display no longer works. Tech seemed to think it was a problem with the power supply. Any ideas on that? If so do you know where I could get the parts to replace and fix it? Great video by the way
seems to be a pretty good amp.copper screws for the transistors.
what is that you use with your soldering gun?not the thing that solders,the other one
Yeah your right about that,I went to turn on the amp and i heard a loud snap and flash..I thought the transformer went,but it was the circuit lifting up from the board soldered it tested it same thing so i put a jumper on it.the yamaha RX-V2500's fan circuit is still not working so i improvised it with it's own power supply Until i can order a new board.I know yes i am an amateur,but thank you for your informative video's.
Hi... I have this receiver. I haven't used it for the last few years due to house reno.... Today I hooked it back up today and was listening to it for about 45 mins. When I moved the receiver into the stand the front speakers and the rear speakers stopped working..... the center channel and sub are still working. I've been thinking I pushed a button or something..... Now 2 hours later and I've tried every setting.... I'm guessing this might be internal.... any thoughts?
Sorry didn't reply sooner. Don't have any Kenwood service data. Blue flashing in the relay sound like a serious short in there somewhere. This could involve working around some hazardous AC voltages. If you are comfortable doing so, unload the transformer secondary and see if the clicking / flashing continue. Also, if it blew the fuse, DO NOT replace it with a higher value or tinfoil it.
Thanks Mark. the US part may not work as it is not calibrated to 230-250V AC . I did google but could not find any supplier stocking the part. Will fetch it from the service center and try if removing the rust help. Otherwise, i dont see much options because I dont of anyone here who can work at the component level.
If the bias transistor is bad I would recommend ordering the Yamaha part number, VK432900. You might be able to get away with a 2SC2603, but the problem is the bias would probably be somewhat at variance with the other channels, and there is no real adjustment provided.
Hello, I have a kenwood GE7030 equalizer Thats being a real pain.I have the service manual and ive checked all spots for proper voltage and they seem fine.Before it started to go it would sound like distortion on both channels,It would do this off and on untill it died.the display works fine but no sound and the bands display nothing.It also powers on and off with no problems.On the amp board i replaced 3 high speed diodes that looked like thay have gotten pretty hot but still nothing.
hi john it was capacitor that blew up completely did not see it before there is one more cap i don't know if its thermal paste on it or leaking mind you i got these receiver on ebay and it look like it was brand new no dust the fan and the capacitor fix so far must have been a lemon i don't know how to post pictures on youtube but i took some of the blown capacitor and board
Hi Mark,
My Yamaha RXV661 which was running fine for the last 4 years suddently refused to turn on. I was trying to plug and unplug a few devices from the same power plug when I found the 2 of the SCENE button LED turn on for a while. Thereafter, the device simply refuses to turn on. Checked the fuse out of common sense, but they seem ok. What could have gone wrong. Will appreciate your inputs Mark.
...
Hi Mark,
My knowledge of electronics is very basic.
I have a Yamaha RX-V773. Failed while watching TV - while at normal volume...
The red power LED glows dim, no other display visible. Press the on/off button on the remote, the red led flashes dim.
The fuse "was" OK, until I tried to do the factory reset to default. As soon as I pressed the button combination on the front panel to attempt the factory reset, there was a big flash as the fuse "went open circuit".
With the fuse open circuit and using a couple of different control panel button combinations, the front panel does light up with text and numbers... This proves the front panel still works - but I think that's it - probably nothing useful in the display
I do not know if a test I performed proves anything, but connecting my multi meter (set to ohms) across the speaker output connections gives a resistance reading on all channels EXCEPT centre, left surround and right surround. So, that is 3 speaker connections adjacent each other that look bad to me (unless this test is useless of course).
Some history - which may have been the beginning of the failure, some months ago, the centre channel started to cut-in and out... I thought the amp was history so I went out and bought a Denon. While performing the unit change over, I found that one of the centre channel speaker wires had come out of the connector =:-( .... Anyway, the Yamaha still worked after re-connection the speaker wire, so I installed it at my holiday house where it worked fine for some weeks, until it failed a few weeks ago while watching TV....
Sorry, not much info, but on this brief description, what is your feeling - trash it or do you think it is worth fixing. Is my output test valid?
Thanks Mark,
Jim (in AUS)
If it blows the main fuse something is seriously shorted. Yamaha's protection circuits work so fast in the event of a current overload, they usually cut off before a fuse can even blow. Anyway, forget about checking resistance at the speaker terminals for now. Check resistance emitter to collector of the output transistors, focusing first on the channel you were having problems with.
If there's no particular issues found there, check for a short from the collector of any NPN output transistor to chassis ground; do the same for any one of the PNP outputs. (each channel's NPN collectors are tied together inside, so are the PNP's) Occasionally there is a bad mica insulator. If this is the case the can also be a carbon path formed from that screw hole in the heat sink, right up through the body of the transistor. In this case the transistor must be replaced along with the mica. Merely trying to clean away the carbon as a fix will not hold - I been stung on that one before.
I had another Yamaha a couple days ago with a similar symptom. One of the main filter capacitors was shorted . Fuse blown - measured dead short from the collectors of (PNP or NPN - I forget which) output transistors to ground.
G'day Mark, thanks for the update. Just wondering if you might be able to point me in the right direction to download a wiring diagram for my RX-V773.... Been searching but not having much luck.
Thanks,
Jim
jim.stapenell@gmail. com
You can email me direct at mark_zacharias@labolgcbs.net and reverse"labolgcbs" to read "sbcglobal". I can send the manual in RAR chunks.
G'day Mark,
I did reply to your email address - did you receive my message?..... As it happens, I found a manual online for an RX-V673 which I think is similar to my RX-V773... Anyway, I wonder if you might be able to comment on something I found. My relay does NOT click when the power button is pressed. I unscrewed the board with the relay - fitted clip leads between the ground points on the board and the unit metal frame. I then switched on the power, applied multi meter to measure the voltage between the closely grouped 5v and ground (?) at the 11 pin plug connector - I measured the voltage OK, but when the multi meter leads contacted the 5v & Ground points, the relay clicked.
From this info, can you possibly identify any obvious faulty components - or at least group of parts I could replace as a test.
I know this request is a long shot but thought I would ask anyway. The reason the relay clicked when I connected the multi meter is probably because I had the board disconnected from the 11 pin plug? Who knows....
Let me know if you did get my email...
Thanks Mark,
Jim
the unit work perfectly, if i wait some seconds between power on/standby operaton. if this is a normal operation, i'll go close the cover of the unit. Thanks for your help, and before i forget, nice videos (but a little dangerous for curious people) you posted.
Sorry about any errors in text. see ya.
Thanks mdzacharias i open my receiver and fixed a broke fan and change two fuse thant blown going to try your advice two questions though when i unplug the hdmi board the receiver does not shut off clicks on and then off over and over but the power does not blow is it possible its bad caps on hdmi boards like the other onkyo's. One more question i have seen your reviews of the multimeters can you recommend a good starter meter on the cheaper side that can handle voltages of a audio receiver
No, it doesn't. I also visited the local yamaha service center and they said that the DSP PCB has got rusted for whatever reasons. Also gave the faulty PCB part no WJ698200 which needs to be replaced. Now, this PCB is not available in India. Can you suggest where should I get this from.
I think you need to look at the PRV line on the Main (2) board. It's the board along the top of the heat sink, so you should be able to get to stuff pretty easy. The PRV line sums all the power supply lines and provides an error voltage for the microprocessor. This winds up over at IC21 pin 35. Occasionally the backup capacitor C103 might leak and give false trigger on the micro but usually just a bad regulator over on Main (2).
I found the can that blew off the cap down in the receiver and it reads 16v4uf. They didn't have that at radio shack. Will a more common one do? The cap was in that assembly that screws to the heat sink above the stuff you are working on and has two 5 or 6 lead cables coming off it. Also wondering what soldering iron and vac you are using. Thanks, Scott
Scott Young You can solder in a 4.7uF at 16 or 25 volts. Cut the leads fairly short and first solder the original circuit board pads a little, then tin the capacitor leads with solder. You should be able to use the soldering iron to then solder the leads to the board. Be sure to observe polarity of the cap. The old solder station was a junk MCM model and it died. I went back to using my old Weller station. The other device you may have seen is a Denon Instruments desoldering tool. I don't use it much anymore; a friend gave me a hot-air gun with a pinpoint nozzle attachment. Don't know the brand.
Thanks going to try to check those things hopefully but the receiver stays on when i turn it up but past 44 - 45 the sound cuts off not the receiver but im guessing its the same problem
It's the cooling fan,on Power(5) PCB it puts out upto 21 volts. when i reconnect the fan it goes into protect ( the fan circuit that is) and then won't work..I bought the receiver on ebay for $20, the Main(1) PCB was damaged from being dropped on the speaker outputs .The board circuit lines were cracked and i have repaired it jumper wires and works fine now. self diag shows all normal.I didn't want to fully disassemble the whole thing Luckily the troublesome fan circuit is easy access.
I have a Harman Kardon AVR 354 receiver I repaired (replaced L7915) that worked very nice. I didn’t use it for a few months, and then when I plugged it in and turned on, acted strangely. The unit’s front panel lighted up completely (all characters were on). After reset, it functioned “normal” but with repeated (every minute or so) sound dropouts (short, 1s or so). Strangely, during the sound dropouts the front panel blacks out, as if the unit loses power (the power on led is on though), but then comes back and functions well for a little while. In the end (~10 minutes) the sound drops off completely (but the unit stays on, and the front panel working OK), or turns into a whistle. This happens in all sound modes, all inputs, with or without any external connections (even with no speakers - reacts the same, you can tell that from the front panel blackout). Between the sound/display dropouts it functions completely “normal”. I tried repeated resets, doesn’t change anything. The F110, F111 fuses and wire (jumper) from HDMI board to Regulator board upgrades have been addressed by the previous owner. I didn’t see anything similar on Internet, have you encountered this issue before?
@RSethTV No, it's homemade. A small 6.3 transformer and a few resistors in a project box, hooked up to a BK scope in X-Y mode.
Not sure if you meant to say you had already disconnected the collectors from the heatsink. Anyway, don't ignore the bias transistors, they don't fail often but can take out the output transistors in a hurry.
Great video posts, Mark. I have an RX-V667 that is tripping circuit protection on DC after a lightening strike. All values in the diagnostic menu are normal except for P1-1 (DC_PRT on IC902) showing value 0 instead of normal 32 to 74. Is there a place to start before looking at each amp channel?
***** Start the receiver in protection cancel mode and see if there is a DC offset on one or more channels. DC on one channels obviously means that channels needs repair. More than one is a power supply problem of some sort, or there could be a problem involving Q1072 (not) providing a -12.6 volt bias to all amp channels.
Great video,
My yamaha RX- V640 shutdown right after i press power button.I hear a click then the screen comes on and it goes back off.After it shuts down i see DC offset on the emitter resistors.What are should i check for that kind of behavior?
I have a Yamaha htr 5440 receiver and no channels were blown blown channels are usually caused by wiring your speakers at too low of an impedance like if the impedance is lower than what the receiver is able to handle
It works otherwise? Does not sound like much of an issue. May even be normal operation.
@killerkoop33 I cannot find this model number listed. Not a U.S. model anyway. This could take some real troubleshooting. Are you a technician? The likelihood is either a bad main power transformer or a high-current shutdown, such as might be caused by a blown amp channel.
Thanks for your reply. Assuming that there are some faulty and shorted circuits already, and since voltages are maintained, does that mean that the risk to fry/damage (even more) some components is increased, due to longer exposure to high current?
I am bit familiar with electronics. I checked all C4468 and A1695 transistors with DMM, could not find any shorted ones. I have not checked at resistors and diode yet.
You can use 2SC4027 and 2SA1552. Be careful - they are reverse basing from the originals. You can even use 2SC4793 and 2SA1837, but they are much larger TO-220 package.
Hello Mr. Mark
I have a Yamaha rxv459, who hand lights up and running (i listen radio to MD/OUT in other amplifier), but is not output to any audio channel. You can help with;
Assuming the power supply voltages to the HDMI board are OK, if the HDMI indicator on the front panel still lights up on an HDMI source, then probably IC1 is bad on the HDMI board. If the indicator does not light, then likely IC14 is bad. The nomenclature in the service manual appears to misstate which IC is the transmitter and which is the receiver.
Hi Mark,
Yamaha RX-V795a. Shuts off after 0.5 sec. Diagnostic mode quickly (0.5s) shows: "PS PRT 39%". Output transistors (C3856 / A1492 pairs) look OK in circuit. The Noble resistors look OK. The regulator 7812 (x2), 7912 and 7805 (all on the main heatsink) have the proper voltage. Mind you, I only have 0.5 sec to do the measurements. Is there any way to increase this time? I can’t measure the DC offset, too short a time.
Actually used a "octopus" or "curve tracer". You can Google Octopus component tester. for info. A diode check on a regular multimeter also works fine. A leaky diode like the one in the video measures low both ways.
The big resistor you see is 750 ohms. It's good when the voltages to be bled are over 20 volts. Less than 20 volts I'll often use an 8 ohm 20 watt resistor - they're common around my shop.
i have a yamaha rx v1900 av receiver,both right and left channels were shorted out destroying four power transistors,four driver transistors,two 5.1v zener diodes,two 220 ohms resistors,also one of the power supplies were damaged that supply the main amp board with a dual plus and minus 61 volts,this has been repaired but the main amp board is dragging the dual supply down very low,i cannot find any more shorts on the main amp board that may be causing this problem,can you please advise me.
C3856 tested bad after all, but I am not sure that this was the original problem. If that was the case, why would have the receiver in diagnostic mode, tested a PS PRT voltage issue? Maybe this developed afterwards. Anyway, I will stick to the original plan (to replace both the power and driver transistors for that channel), and I will let you know... in a month!
Have the same receiver - and I think a lightning surge took out my HDMI circuits. It turns on, but seems like no signal is coming out of either channel. Do you know what it would take to fix this?
My guess is that it would work but maybe be more NTSC than PAL for example. HDMI codecs and permissions are way over my head. Internal voltages would be compatible, but even with that I'm not sure it would work. I would suggest another used 661 might be a better option, maybe a broken one with other problems.
@mdzacharias It's not an integrated amp,it's a power amp Sony TA-N80ES.I've heard that this is common for this power amp.of course it was the end of a lot of them :(
So the fans won't "hurt" the transistors in any way.Thank you
I got that last part in fixed that but my sound still cuts out at about 45 or so and was able to stay on for a few seconds at a higher volume i am not sure seems like something with the front cover because it did stay on at almost max volume. But it still says check speaker wire for the first 10 seconds when i first power on the unit after plugging it in to the wall for the first time.
Thanks! Yes, HDMI indicator did light up when it got the signal (when i used the selector). So that is good to know. Any idea how much say IC1 should cost, or in general, to repair something like that? (Not that I want to replace it myself - a cap or a resistor, I can handle. Not a chip).
Yes but there would have to be some appropriate resistance in the setup to limit the current plot on the scope screen. The curve tracer produces a VI plot of voltage versus current on the scope screen. Search for "oscilloscope component tester" on youtube, should show how it works.
@costellom5 Also if yours gets hot that is a warning sign. Lots of people overwork these things. They can and will blow up if you run them too hard for too long. I suppose the fans are a good idea.
goodmorning, mark, i have a yamaha rxv 661 and sometime ago i was playing a CD i had just gotten whilst i was in the yard. unknown to me the CD was recorded high and so when i heard the volume came up i ran to lower it but was too l8t. the reciever just shut down n i waited a few minutes then turned back on i saw the display but shortly after the power just went back off i tried it again this time all i heard was TWO CLICKS. what do u think is my problem and can it be fixed?
Hello mark i have a rx v373 with Dc prt 255 hi error can you please guide me where to start checking for faulty components.
I know this video has been uploaded from 8 years but hope you still can help me thank you in advance
Hi mdzacharias, I have got RX-V630 which turns on for a brief moment and shuts down. Sometimes there is message check SP wire on start. I have disconnected all my speakers but still the problem remains. Can you guide me on where the problem would be or have you got a circuit diagram for it?
i have a kenwood that was turning its self on and off but would still work now it wont come on the main relay clicks rapidly and has blue flash in it you think it could be the transistors?
Hay mark i was able to get the receiver to turn on loosing the front cover it turned i turned up the volume it stayed on with no speakers attached and then i put the back and front cover on it would not work loosened the front and got it to turn on5 seconds later a power transistor blew the part number is SK C4468 i only found them on ebay in like china any were you know of in america were i can get them sooner
Nice work, I have a yamaha rx-v667 and it works great but i have trouble getting radio stations to come in. after looking it over i see the antenna plug is bent up kind of funny and I'm thinking this might be a bad connection. would this be easy to fix?
Should I take it to a shop? I have done some soldering before but wanted to ask. thank you.
dankbobby The tuner is a complete module and fairly easy top replace except it is situated kind of underneath the HDMI board. The part number is WQ756600. List price is about 40.00
Mark Zacharias
Thank you very much.
Mark,
I have a RXV-665 that has the STK443-130 amps....The unit had a similar problem,shutdown and I can get the self diagnostic to read - DC PRT :075H
Do you have any experience or tips on this model,,?
Thanks,
Steve
Steve Bavis The receiver can be forced to stay on for troubleshooting. Are you a technician?
@killerkoop33 The power transformer usually only goes out if you've been running it really hard for a couple hours.The transformer can be checked by a knowledgeable person. Also Yamaha with a blown channel may pull so much current at turn-on that the protect is triggered instantly, you never even see the display come on. If the transformer is OK this is probably the case. I wouldn't recommend just ordering the transformer til you know it's bad. About 135.00+frt. US model.
Hi Mark, I have a Yamaha RXV 661 Receiver and the Polk Rtia 3 connected to it via the front A and front B/ zone 2 with extra SP assign mode.
It only plays the LEFT SPKRS woofer & RIGHT SPKRS tweeter. Can u pls throw light on the issue as I am not able to know work it out.
Sounds like the speakers are the problem.
Hi Mark, I have a RX V477 working on, its brand new, got off Ebay, in protect mode. Got into the diagnostic mode, first of all I don't understand what all that stuff means in diagnostic mode, so far I pulled and replaced all the output transistors, I had already bought all 10 anyway, but the old ones checked fine as did the emitter resistors, I'm new to electronics, went to school and trying out a few of these bad stereos to get some experience. What I need is a schematic of the power amp section, can't find it for purchase or free. And something about how the fault mode codes work. Apparently I have some other bad items in there I failed to check. BTW in fault mode I seem to have one dead front channel. Good learning experience!! Thanks for the help. Subscribed!!
+Vernon Bosshard This vid cleared up a lot of confusion, so much crap on the net about why units go into protect mode, but from what I read is its always due to DC offset on the power transistors or something to do with the power amp section causing a fault. I bought a few units off Ebay for practice, got a Sony and found the schematic online. What size resistor do you use as a Cap bleed off?
+Vernon Bosshard www.hifiengine.com/manual_library/yamaha/rx-v477.shtml
You have to register but it's free.
+Vernon Bosshard I often use a 750 ohm 20 watt resistor to bleed of the higher voltages, especially if the voltage on a particular unit doesn't bleed off by itself. Lower voltages sometimes I'll use a larger eight ohm resistor because it bleeds off faster.
I do not know what "coil" you are talking about. The primary of the main power transformer would read much less I would think, and still be OK. If you measure OHMS at CB155 on the Operation 3 board (standby power board) and it reads low, the main transformer is ok. At this point you probably have a blown (shorted) amplifier IC. These are somewhat expensive and mostly only available from Yamaha.
hello, i'm a technician from Brasil, and i had some troubles with the receiver that i already repair, the unit fails to turn on if i press the power button right after set the unit to stand by, i have to wait 5 seconds before turn on the unit again, i already repair the (-bv and -bi) lines, after the unit is on, al voltages and protection circuits are normal, do you have any idea to fix this issue, the unit is a Receiver Yamaha RX-V730.
never mind it was a capacitor that blew im blind i fixed it does not look like anything else is bad i need a multimeter i would post a picture not sure how it is the board in front of the amp like your fixing in the video it has the output transistors im not sure but im guessing the Channel with the capacitor that blew up amp channel with problem
hi i had a question how would i fix my ir sensor on my harman kardon avr 40 i bought a new remote for it but the receiver isnt working with the remote and the remote works good.
ive not bolted back the main amp board to the heatsink and ive disconnected the thick power wires from the collectors of the power transistors cause ive already had 4 more power and driver transistors go short on me cause of a fault with the plus and minus 61 volt driver supplies,there seems to be something on the main amp board causing the dual supply to be very low,im having to run the amp in diagnostic mode so i can test but i dont know what else to do and yamaha uk are very unhelpful.
Are you bleeding down the B+ and B- lines with that resistor? Also, what value of resistor do you use?
Thanks,
Ben Huebner
Thanks alot. I love watching your troubleshooting..
Nice video! I have one of these that just came in our store and the owner said they were listening to it LOUD and it went off and now when you hit the power button there is nothing. Any ideas? Think it is fixable?
UPDATE: I can hear a click on then off.
Ken Shipley Need to check the primary of the power transformer.
You may have damaged some of your new parts, but I would look at possibly damaged or missing mica (or rubber) insulators.for the outputs. Could be a collector is shorted to the heatsink.
Is it possible to run a 6.3 volt sin wave into the component via a frequency generator, then measure the component via ocsilloscope in XY mode?
This is actually a very common problem with these. Are you a technician? The bad parts are on the main board, kind of hard to get to. Everything has to come out and parts soldered in from underneath.
Hey mark love thank you for this video I have the exact issue with my v661 I have done changed the output transistors but am struggling with the other repairs like the driver transistor I need assistance with the range it should read when tested normally and furthermore. I would like to if possible repair as I would hate to see it end as land fill. Any help would be grateful.
+Andrew Shorter If the outputs were bad ASSUME the drivers are bad, also the 5.1 volt zener diode. Also check the resistor between the emitters of the driver transistors. After these parts replaced, check resistance from base to base of the output transistors and compare to other channels(s).
Well, a variac would be nice. You could put a 100 watt light bulb in place of the main fuse. If it glows bright, there's an over-current situation. This really seems more like a power supply thing though, and the PS PRT error code backs me up on that.
Mark, I have a Yamaha RX-V2090 that I bought new (for $1549!) somewhere around 1996. It has been a great unit, but over the years has lost some of the channels for the speaker outputs. I have downloaded the service manual, I opened up the case tonight, and am looking for obvious signs, like discolored boards, but am not quite sure where to begin testing. Any advice on where to start? Thank you!
I think I would get the receiver into diagnostic mode and reset to defaults. Good place to start anyway. Under "Preset Inh" switch to "Preset RSRV"
Mark Zacharias Thanks for the reply. I have figured out how to get it in diagnostic mode, but it seems some of my buttons are sticking. For example, if I push "Tape 1", the "Tape 2 Monitor" comes up.
It seems a few of the buttons are mixed up with the one next to it. I do have the remote, but has the same issues. I'm not too surprised for an 18 year old unit. What can I use to clean them up with?
Can I contact you off of youtube? I may have a lot of questions, if you are willing to help...
Thanks!
I was able to take the remote apart and clean it. It appeared someone (besides me) poured a few cans of Pepsi inside. I just (carefully) used soap and water to clean the contact side and the button 'sheet'. It has never looked so good! Would something like rubbing alcohol also have worked on this, and/or the receiver?
You have serious problems now - the amp channel is blown like in the video. The transistor number is abbreviated. The number is 2SC4468 and it's complement is 2SA1695. The drivers are also blown, probably also the 5.1 volt zener diode, maybe some other parts.
Probably either the remote receiver itself is bad (it happens) or maybe there are bad solder connections there at the IR receiver module. This also is pretty common. Way down the list would be some other fault in that area, a circuit board flaw, leaky cap, bad microprocessor, etc.
Wierd i was able to get audio when turning it on just now but when i pluged in the fm antenna it shut back off. There is a fan inside that is not working does that cause the receiver to power off like that its 120mm fan was going to replace it
Hi Mark, Am bothering you again. Is it possible to arrange a WJ697500 from USA. Will it be compatible with the RXV 661 ( L model).
Ok, I can't quit. So I checked the noble resistor and it is bad. I going to replace those two transistors also 'cause they are so cheap and apparently go bad. But can you say how to mimic that noble dual emitter with p/n mcm 28-0520 (since that part not available)?
Scott Young You might want to double check that resistor - they rarely go bad on the Yamaha's. If the outputs are bad I guarantee the drivers are bad, and probably the 5.1volt zener diode as well. Also the 100 ohm resistor that sits between the emitters of the drivers should be checked. I haven't seen dual .22 ohm 5 watt resistors on eBay. If it's really bad, usually only 1/2 is bad and the other half could be bypassed with a single. If you're in the U.S. B&D Enterprises would have the dual, I'm sure. I have a drawer full of the things at work. They're really common if you work on these things. Many of those I have are pulled from scrappers.
I would definitely be looking at the power supplies, like plus and minus 15 volt (maybe + or - 12 volt) lines, also any muting circuit that may be used.
Mark great videos you inspirated to me to fix my first receiver it an ONKYO HT-RC360 and it has issue like sidsasi described. The receiver has a clicking sound when powered on. It show a quick message saying check speaker wire before it turns off. The display only shows the message for about half a second before powering off. Im hopeing its bad capacitor all i know how to fix lol thanks for videos
Well i am but out of money on this puppy i tested with the meter and found 3 more bad transistors 2 sk1695 and 1 more stc4468 now i thought it was fixed put it back together and it says check speaker wire one the first power up on the second it stays on. I thought i just had to hook speakers up tried that but when i put like fm radio on when the speakers are about to show it clicks off.
Update2. I tracked the high voltage, back to transistor Q708 (NPN, C2240). I replaced it, and now the readings at the Q716C (NPN power transistor RL) are much closer to the schematics: the transistor base reading changed from 6.2 V to 0.47 (0.4 on schematics). Unfortunately the symptoms are identical, and the display still shows the same PS PRT 39%. Other voltages are OK, no DC offset… I wonder if I can reset the unit, but how, since the display is gone in 0.5 sec. I guess I am stuck.
@ mark zacharias .Do you repair these receivers for the public. I have a Yamaha RX-v665 that I believe may have been damaged from a lightning surge. Having trouble trying to find someone near me who can repair it.
I'm not really wanting to deal with shipping and receiving and all that; and besides, lightning can be pretty devastating, often unrepairable. What is the receiver doing wrong? And are you sure it was lightning?
If you ever come across a Yamaha RX-V2500 and up for repair please upload a video if possible.
@costellom5 You mean the desoldering braid? Pretty common in my work. I also was using a spring loaded solder removal pump, if I recall. I don't use that so much these days - too easy to mess up the solder pads.
Hi, i have an amplifier which hv the label on the motherboard for the capacitor to be 2200uF 35V. However, the manufacture put 1000uF 35V caps in it. can i replace it wh the 2200uF 35V caps instead according to the board?
Normally this would work fine but I would not necessarily expect any improvement unless one or both of the existing capacitors were defective.
hold together straight + audio select , then press master button / diag mode
9. factory preset / change to RSRV
press standby button
that's all , error log cleaned
Just curious if you've run into the same issue with a rx-v795a Yamaha and if it could possibly be the same fix? Seems like every blog I've read says something different. Relay clicks but no power. Thanks and good work!
+Justin Bergendahl The most common thing is a blown amp channel caused by bad solder connections at the bias transistors. I would check continuity of the main power transformer first. If the unit went out after playing too loud for too long, the transformer could be bad. You need some skills like soldering and know how to use a multimeter or you're probably out of your depth on this one.
+Mark Zacharias well I changed the relay on the main power thinking it was the problem but still getting the issue. Main transformer has 120v. The aux outlets work without power on. It has to be within the amp or a capacitor dried out. You obviously deal with these a lot. Just trying to narrow it down. All help is much appreciated
+Justin Bergendahl You should check continuity or the primary winding of the main power transformer.Should read a very low DC resistance. UNPLUG from the wall first! Next check for emitter-collector shorts on the output transistors. The smaller amp board amp channel nearest the rear of the unit is most common.
In the diagnosis mode of Yamaha htr 6030 a message for a very short time
"PVR PRT 59"is displayed and the receiver shuts down.
What does it mean and where does the fault lie? It definitely means power supply issue but what does the number 59 signify ?
Indicates a power supply problem. There is a Protection Cancel mode that will allow you to keep the unit ON while you troubleshoot. email me at mark_zacharias@sbcglobal.net and I can email you the service manual. Most likely a bad voltage regulator IC like a 7812, 7912, etc.
Thanks a lot Mark.
My email is balrajacharya@gmail.com
Wow. I need to know a lot more. What model Kenwood? Are you a technical type person? Are you able to take voltage readings, etc?
Hi Mark. I have been looking though your videos seeing if you have encountered my problem. I have a Yamaha RX-V667 receiver. It was working fine until recently it started constantly switching DSP modes. Its happening intermittently. I some of the other buttons on the front are also activating. Is it possible just to replace the front panel? Where could the replacement part be ordered?
pvdeluca Kind of unusual problem. The front panel switches are part of a couple of resistive networks. Any leakage could trigger this. Like if some liquid got in there somehow, maybe causing some corrosion. Tact switches can also be leaky but this is less likely. The part number for the front board is WU427500 for the U.S. model only. Ending in 600 or 700 for other markets. Probably fairly expensive.
Mark Zacharias Hey thanks for the response. Ive googed for days to find someone with the same problem. My apartment is very humid so this might have caused the issue. Too bad it was a great amp. It would feel like such a waste if i didn't get this repaired.
Yes it stays on and can get audio but it shuts off when i turn it up pass 40 thats about half way that would be just like if i speaker wire cross but i don't still inside the receiver then back to the drawing board people
Mark, great video! I have a BA in EE but haven't really used anything I learned since I got my new job. I have a Yamaha Rx-v765 that I believe is in high current shut down mode like the one in this video. When I plug it in I hear 3 clicks from the 3 relays but there is no display. I have checked voltage going to the display and it measures close to what the service manual says it should have.
Do you happen to have any tips or tricks to verify it is in high current shut down mode or any other tips on where to begin troubleshooting?
Part of me says I should just send it in for repair but my inner nerd is telling me I should be able to fix it myself.
These can have a variety of problems. If the main power supply voltages to the output transistors is staying on, then probably not a high current shutdown. Maybe the display circuit - maybe a blown channel. I would start by looking for any shorted output transistors. I can probably send you a pdf of the service manual.
Mark Zacharias I have the service manual but everything I have checked so far seems to be correct. I haven't dug to deep into yet though. I basically just checked a few things I could easily get to like transformer and display board voltage.
I was only using the rear speaker outputs at the time it went out as my main speakers are powered.
I should also note there is about 56 volts going to the chassis.
I will check the output transistors next. I appreciate the reply.
Mark Zacharias
None of the output transistors appear to be shorted as far as I can tell. They all have high resistance across collector and emitter. I'm not saying my in circuit transistor testing is 100% percent accurate either though. I may do some more exploring in the display circuit.
Mark, I think I may have found an issue. There is a 25 pin ribbon cable that goes from the main video board to the display circuit. When analyzing the voltages coming out of the video board to the ribbon cable there are several discrepancies. Pin 24 which is labeled 3.3DSP is supposed to be 3.4 but I am reading only 1v. Is that just because of another problem and the microprocessor is telling the display not to turn on or could the processor itself be damaged.
I think I maybe getting in over my head here but it is certainly fun. Sorry for hijacking your video.
Jeremy Meyer
I have seen things like this cause a "no display" problem. In my case. I replace the digital board, where the 3.3D (for display) is generated. (Seen this twice only)
Hi mark i actually found a part on a board that exploded its not a capacitor or a transistor but is on the same board output transistors you told me to check i put the part number in google and some part site no luck it says C5443 little black think with one flat side one curved i post a picture if i could any help would be greatly appreciated