I just repaired an Hot Rod Deville with this exact same problem. One thing to note, those screws on the inside are just holding the standoffs to the board. You can take the external screws off on the underside around the tube sockets and remove that board without removing the main board. 9 times out of 10 though I recommend to the customer to replace the filter caps so I end up taking the main board off anyway.
Terry, I had one of those amps (a '95 IIRC.) It didn't have low output, thankfully. Gave it to my son a few years ago, because despite the relative small size, it was still a bear to carry into and out of places where I used to play. Bought a Super Champ XD, and have been in love with the ability to carry in something that feels at least 30 pounds lighter (and these days, I don't play much at all, but even when I did, as a rhythm player I didn't need more volume than the 15 watts on the SC could provide.) Always enjoy your content, and thumbs up!
The same 82K ohm resistor on my 96 DeVille was open, I replaced it and the amp is working again. Thanks for posting , I also installed the new resistor on top like you did
Yep, lots of board swapping these days. This was just an example of a quick method. There are many ways to accomplish the same thing. I'm still wondering what took out the original 82K resistor.
I'm not a scientist, but I believe that a component ran at it's upper limits can receive some kind of electrical or frequency vibrations that cause it to fail. I saw a 1/8W resister mounted vertically one time have the long lead snapped into. Looking at the leads under a microscope, the leads looked like they were bent many times back and forth and snapped but there was no way that was possible. I replaced the resistor with a 1/4W and it worked well. In a case like that, I would replace the component with the next higher power rating. Maybe the resistor just had a manufacturing flaw in it somewhere.
I always learn something when I watch your videos; however, those two 470 Ohm 5W resistors need to be replaced with resistors that will bring the resistors above the board. They get hot enough to to not only brown the board (which is plain to see in the video), but they can also cause the solder joints to separate, as well as burn other components/leads/joints near them. Re-soldering doesn't fix the problem, it just means the amp will need to be serviced again in the near future. One other item of note, the bottom tube board has screws below the chassis that can be removed to allow access to the underside of the board. that way you don't need to remove the top board before removing the bottom board. How do I know? Just spent several days repairing a HRDx with these exact same issues, plus a few more . . . talk about hunting gremlins. It's too bad Fender has gone to making amps that aren't as reliable and easy to work on as they once were.
Just noticed the same thing you mentioned about the tube board. The standoff screws are accessible to enable a tech to remove just that board, but it could be possible that not ever version was the same. It would surprise me if Terry would have missed this fact.
It has been said if you change the phase inverter tube from a 12AX7 to a 12AT7, it is a more robust tube, a little less gain but supplies more current or signal strength because of the characteristics of the tube. Of course the manufacturer makes a difference. Having all the same preamp tubes simplifies replacement. Certainly in a long tail phase inverter, you want the tube to be balanced. I changed the PI in a Vox AC 15 from a 12AX7 to a 12AT7 and it gave a noticeable amount of headroom. I left the factory Chinese preamp tubes in(12AX7s)and it got a little clearer and then I changed the preamp tubes(12AX7s) to JJs and the amp got a lot clearer and it did not go into distortion until about 6 on a scale of 10. That in it self provided more clear headroom. Was this a fluke? What is your valued opinion of this change? I think amps like Fender Bassmans have 12AT7s for PIs to deliver more clear and higher levels of bass tones. Love ALL your videos. I would like someday in my travels to meet you and express in person the thanks and graduate all of your viewers share with me! Thanxz
Just picked up a 2005 Hot Rod Deluxe...the filter caps are not original, but they are leaking, so I'm watching your videos to learn how to replace them myself...will also check the 2 suspect resistors and all ribbon cable solder joints...you recommend NEVER using the solder sucker on these boards?...I've never used the solder wick, but there's always a first time...you do great work and I enjoy the videos. What's your opinion of replacing the last AX7 with an AT7 to cut output?...I've heard it also makes the overdrive channel a bit more palatable...thoughts?
Hi Terry, this was a fun video. I must be learning something from you (and Uncle Doug). As soon as you put the scope on and I saw that ratty sine wave, I said "phase inverter". Either that or the turbo encabulator. Love the videos, have a nice cab on me...
Hello Terry and many thanks for your videos ! I would like to know if soldering the resistance on the 2x2 points seems Ok because there is no other Resistor on those points on the PCB? Am I right thinking that? Many thanks Philippe
Oh Terry. I have been watching your videos for a long time, and love almost everything you put out. However, in this instance you did your customer a slight disservice. 1) carbon comp for the 82k replace? I get replacing carbon comp for carbon comp, but replacing a carbon film with a carbon comp? Doh! These SOB's run HOT! 2) any time you are in fender HRD, you should always replace/correct the horrible design flaw of having the 470 ohm, 5W resistors mounted directly on the PCB and replace them with 10w and get them elevated off the board. Otherwise, the issue with cracked joints just continues to happen.
Matter of opinion. Some say that the new metal film resistors have inductive properties, which can induce noise. Most of my customers ask for carbon comp type. I stock mostly 5% carbon new issue type. No reports of failures. As for the 5W stock type, That is as designed by Fender. I am here to repair at low cost due this area. If this were a vintage collectors amp, things would be handled differently. Sorry that you disagree, however I am in this to help out local bands at a reasonable cost plus timing. Remember, I present these videos as reference. Everyone out there has a choice. Thanks for watching
Fantastic video! What specifically should I order for Caps on my HRD? I'd like to get them ordered before I take the beast apart! I'd rather buy the expensive ones, not sure if they have a part number and who is a supplier...thank you so very much!
D-Lab. How much hum is acceptable? Could you give a peak-to-peak voltage value at the load (load resistor ir speaker) that you would consider acceptable? Also would need the load impedance. I ask this because I bought my first tube amp being a Fender Jr. Even with ALL the tubes removed it has a hum when immediately turned on that I do not know is normal or not. I have a scope and would like to duplicate you output test setup. I do not want to re-cap if not really needed. Thanks. Really enjoy your videos and information. Also what do you think about re-capping by not removing the circuit board and instead cutting the leads near the cap; remove the bad cap; put the new cap in; and then attaching the new cap leads to the "left standing" old cap leads. You could bend the wires to get a good physical connection and then solder to get a good electrical connection. This is similar to making the decision to solder to the available side of the circuit board instead of spending the time to remove. Thanks.
Hi Terry, question on the Oscilliscope SIN Wave. you mention which pins you connect to on the output tubes, that you add a resister load to the output in place of a speaker, then you inject the audio signal to the PreAmp is that right? Maybe a short video on the all the setup and tools you use or recommend would useful for some of us. My question is the shape of the SIN diagnosis. When you saw the wave clipped on the up side you immediately said it was a problem with the blah blah. When I used to to Cars and engine diagnosis we used a scope on the spark plug signal and could diagnosis issue based in the shape of that trace of the Spark energy build and drain. It seems you could build up a image video of the various shapes of the SIN wave and what it says to you about the condition or calibration of the tube systems. Am i right in that analogy and could you do such a video for us. I have a scope and am searching for a cheap enough Signal generator then I want to test, measure, diagnose, repair or calibrate all the tube stuff I can get my hands on. I think this would be extremely educational. If you have already done such a video I am sorry i may have missed. let us know where to look. I had seen a video on the operation of a VTVM that explains how it gets its accuracy and thought Wow! that is a great method, balanced signal gets off balance etc etc. Anyway great stuff, thank you so much. I wondered if you get a unknown radio or amplifier could this test be used early on in the discovery to help shape the state or condition of the tube circuits??? D
Hello Dennis, Those sound like good video subjects. Have a back log in the shop right now, but when things slow down I will get something rolling. Appreciate you being part of the D-Lab team. TD
This is a really great video very enlightening on newer Tube gear and what to look for, i now have a tube tester, Scope and searching for that signal generator look out!
Hey Terry, I see that Fender is using those Illinois capacitors on even the newer HRD IV amps. Would you suggest replacing them on sight, or would you let them go until they start causing any noise or hum issues??
Is it normal to have all that hum coming directly from the power tubes? I've never heard anything like that on other tube amps, but I hear it both in this video (even after the other issues are fixed) and on my Hot Rod Deluxe IV
Liked your “ham” T-shirt! Years ago my mom designed a QSL card with much the same design! 😛
6 лет назад+1
I loved this video.And the comments BECAUSE my HRD is doing the same thing.I am putting her on the back burner-too much backlog staring at me. Funny but on another Amp repair channel he usually replaces bad IC caps with new IC caps 22 year old amp needs new caps obviously of any kind I use Panasonic or NIchicon (look out for fakes)and in the tube/PCB amps I use High temp versions,they cost more. These amp builders could make them last forever with high quality components but then the amp $775 new would be over $1000 One repair and you are defeated It reminds me of the old days- your friendly TV repair guy would come over and fix your set by simply changing the tubes until the TV worked- didn't even bother to see what the voltages were.The TV would work for 4-5 months,cook the tubes,and he'd be back. Job security and pathway to a successful shop.Just have a full tube caddy and try not to get zapped.Or shot.
Man, what a great tech! Simplifies a complex process. I have a Hot Rod Deluxe combo, 1-12. Love that amp. It's my go to amp. I love the bottom end it produces and it's got this just wonderful ambience about it that most of my other amps do not have, so I'm always judging the other amps by the sound that the HRD produces. I also have a 22w Super Sonic that does not have that full ambient tone/vibe to it. Do you have any mods or upgrades that you could do to that amp to give it a fuller output tone? I could just send you the chassis. Thanks for the great vid and the bonus tips thrown in!
Thanks for the video first. My Deluxe has two problems. While playing on the low frets -it starts from the 5th or 6th fret of the 6th string- it buzzes. The other problem is the drive button. The clean tone is ok but when I press the drive button the amp hums and buzzes. Also the sound goes down. I can send you videos if you want. I'd be glad if you help me. Thanks and best wishes.
Hey Terry...how is the reverb tank in a Hot Rod Deluxe fixed or mounted in the back of the amp? Velcro?...screws? The bag is here, there's a cardboard panel in there as well as as the tank itself, but it's free floating around back there...help? Thanks in advance
What do you recommend for a "modern" tube amp? Something that doesn't cook it's own PCB, sounds good, etc? Something affordable would be great too LOL.
You could also desolder the old resistor and push it out and then shake it out of the chassis. Then you can solder the new one on the solder side of the board like you did. I have done this before on this model amplifier and even some old radios.
heY Terry, I have a HRD that basically has working just the clean Channel , out of that , no normal, bright, more bright, channel select, or drive on the clean Chanel would work, and overdrive Chanel is completely dead, all filter caps have been switch to F&T's, new resistors raised above the board, I feel a bit lost, any advice will be appreciate it, thanks!
I've noticed a few times throughout videos you've mentioned the poor quality of the Illinois caps. What brands would you recommend for replacement of filter caps?
@@d-labelectronics Hi! I need to recap a vintage fender amp and following the schematic indicates capacitors of 70uf 350v and 20uf 525v, but it is difficult to find those values. I see a lot of folks putting in place the 70uf 350v, 100uf 350v or 80uf 450v. Regarding the value of uf being close to the value of the scheme is ok, but what about the voltage? can add value without problems? in the circuit of bias the schematic asks 25uf 50v. again I see a lot of people putting 100uf 100v. That's right? Is it okay to add these values? in relation to the operation of the equipment, does it change the final tone of the amplifier? I hope you understood my doubt. Thank you for clarifying this.
Hello, Yes, its always fine to exceed the filter cap voltage rating, never go lower. And yes, I use 80's in the place of those 70uf caps. A little more capacitance wont hurt anything. And yes on the negative bias caps, I always increase the capacitance + voltage ratings of the originals. Just make sure to watch polarity! Have fun. TD
Agreed, F&T/JJ are good affordable caps... Sprague ATOM is the king. Illinois caps were part of the "cap plague" from 1998-2010... Their current production has remedied the issue, but techs don't forgive.
Another good one Terry, now go have a glass of Robert Mondavi. You have to wonder what fool designed that amp like that. That spinning sound you hear is Leo in his grave. He would never have approved such a poor design. Keep them coming.
Terry, I wouldn't ask except My amp is the exact same animal... What about the 3rd 22uf electrolytic at the preamp end... ? Thanx in advance and thanx for another great vid. cheers
I have the same humming issue on mine (the filter cap when nothing connected). Just curious, is it actually the filter cap making the noise or something underneath it on the other site of the board? I cant seem to locate it myself by listening.
outlawrickenbacker I've had a few amps through with them in , and all seems well with them , so I believe there was just those bad batches back then . And Mr Carlson recommends their IC poly caps , so I think they are probably a good quality brand .
Wouldn't it be faster, easier and less expensive to clip the filter caps leaving some leads on each end to use as turrets to install new caps? Similar to how you installed the resistor.
Better to pull the board and resolder questionable solder joints if you have the time. If a customer gets a show wrecked because you were too lazy to pull the board, you will have an angry customer. And word travels fast now-a-days...
Always true... not so much a question of the tech "having the time" but the clients desire and ability to spend the extra money at $30-$50 per hour. In those amps I would say every solder joint is potentially questionable and reflowing them all takes more time and is thus more expensive. Doing the quicker/cheaper job I suggested is in keeping with the method used to replace the resistor so I thought it would be consistent with a $400 amp.
I'm not Terry but as far as the actual tube circuit...no problem. It's when you get into ALL of the solid state circuits including the switching, reverb, etc things would get crazy.
John Rapp why? If I like the amp, use it every week, feel that it has paid for itself, have to buy a new one to replace it, why wouldn’t I spend that cash towards a hand wire job?
Why wouldn’t you just undo the screws from the tube socket side? Then the whole PCB assembly comes out without having to remove the main board. Takes all of about 15 minutes to remove and replace the board.
Too bad you didn't know you were going to remove the board anyway to replace the caps. Then you wouldn't have to solder the resister on the alternate side of the board.
Good diagnosis! But if you go to the following web site: www.ampbooks.com/mobile/amplifier-calculators/long-tailed-pair/calculator/ ou will see the 82K/100K pair is not the best way to balance the phase inverter. If you keep the 82K, you can add a 5K or a 10K potentiometer with the B+ going to the wiper and one of the other lugs to the 82K and the other one to the 100K, to balance your inverted and non-inverted phase that feeds the power tubes.
This is my deal exactly with my new to me Fender Hotrod Deluxe III. Many thanks! I will keep you posted.
Just used this little tutorial to fix my friends DeVille... Fantastic, thank you so much brother!!
I just repaired an Hot Rod Deville with this exact same problem. One thing to note, those screws on the inside are just holding the standoffs to the board. You can take the external screws off on the underside around the tube sockets and remove that board without removing the main board. 9 times out of 10 though I recommend to the customer to replace the filter caps so I end up taking the main board off anyway.
Terry, I had one of those amps (a '95 IIRC.) It didn't have low output, thankfully. Gave it to my son a few years ago, because despite the relative small size, it was still a bear to carry into and out of places where I used to play. Bought a Super Champ XD, and have been in love with the ability to carry in something that feels at least 30 pounds lighter (and these days, I don't play much at all, but even when I did, as a rhythm player I didn't need more volume than the 15 watts on the SC could provide.) Always enjoy your content, and thumbs up!
The same 82K ohm resistor on my 96 DeVille was open, I replaced it and the amp is working again. Thanks for posting , I also installed the new resistor on top like you did
You’re the man Terry. The hacks around here would have replaced all 3 circuit boards and damaged the speaker while doing it. LOL
Yep, lots of board swapping these days. This was just an example of a quick method. There are many ways to accomplish the same thing. I'm still wondering what took out the original 82K resistor.
I'm not a scientist, but I believe that a component ran at it's upper limits can receive some kind of electrical or frequency vibrations that cause it to fail. I saw a 1/8W resister mounted vertically one time have the long lead snapped into. Looking at the leads under a microscope, the leads looked like they were bent many times back and forth and snapped but there was no way that was possible. I replaced the resistor with a 1/4W and it worked well. In a case like that, I would replace the component with the next higher power rating. Maybe the resistor just had a manufacturing flaw in it somewhere.
Another quality job Terry. This made me wonder why the resistor went open in the first place. Likely a bad tube or something I would imagine. Nice job
I always learn something when I watch your videos; however, those two 470 Ohm 5W resistors need to be replaced with resistors that will bring the resistors above the board. They get hot enough to to not only brown the board (which is plain to see in the video), but they can also cause the solder joints to separate, as well as burn other components/leads/joints near them. Re-soldering doesn't fix the problem, it just means the amp will need to be serviced again in the near future. One other item of note, the bottom tube board has screws below the chassis that can be removed to allow access to the underside of the board. that way you don't need to remove the top board before removing the bottom board. How do I know? Just spent several days repairing a HRDx with these exact same issues, plus a few more . . . talk about hunting gremlins. It's too bad Fender has gone to making amps that aren't as reliable and easy to work on as they once were.
Just noticed the same thing you mentioned about the tube board. The standoff screws are accessible to enable a tech to remove just that board, but it could be possible that not ever version was the same. It would surprise me if Terry would have missed this fact.
It has been said if you change the phase inverter tube from a 12AX7 to a 12AT7, it is a more robust tube, a little less gain but supplies more current or signal strength because of the characteristics of the tube. Of course the manufacturer makes a difference. Having all the same preamp tubes simplifies replacement. Certainly in a long tail phase inverter, you want the tube to be balanced. I changed the PI in a Vox AC 15 from a 12AX7 to a 12AT7 and it gave a noticeable amount of headroom. I left the factory Chinese preamp tubes in(12AX7s)and it got a little clearer and then I changed the preamp tubes(12AX7s) to JJs and the amp got a lot clearer and it did not go into distortion until about 6 on a scale of 10. That in it self provided more clear headroom. Was this a fluke? What is your valued opinion of this change? I think amps like Fender Bassmans have 12AT7s for PIs to deliver more clear and higher levels of bass tones. Love ALL your videos. I would like someday in my travels to meet you and express in person the thanks and graduate all of your viewers share with me! Thanxz
Just picked up a 2005 Hot Rod Deluxe...the filter caps are not original, but they are leaking, so I'm watching your videos to learn how to replace them myself...will also check the 2 suspect resistors and all ribbon cable solder joints...you recommend NEVER using the solder sucker on these boards?...I've never used the solder wick, but there's always a first time...you do great work and I enjoy the videos. What's your opinion of replacing the last AX7 with an AT7 to cut output?...I've heard it also makes the overdrive channel a bit more palatable...thoughts?
Hi Terry, this was a fun video. I must be learning something from you (and Uncle Doug). As soon as you put the scope on and I saw that ratty sine wave, I said "phase inverter". Either that or the turbo encabulator. Love the videos, have a nice cab on me...
Hello Terry and many thanks for your videos ! I would like to know if soldering the resistance on the 2x2 points seems Ok because there is no other Resistor on those points on the PCB? Am I right thinking that? Many thanks Philippe
Oh Terry. I have been watching your videos for a long time, and love almost everything you put out. However, in this instance you did your customer a slight disservice. 1) carbon comp for the 82k replace? I get replacing carbon comp for carbon comp, but replacing a carbon film with a carbon comp? Doh! These SOB's run HOT! 2) any time you are in fender HRD, you should always replace/correct the horrible design flaw of having the 470 ohm, 5W resistors mounted directly on the PCB and replace them with 10w and get them elevated off the board. Otherwise, the issue with cracked joints just continues to happen.
Matter of opinion. Some say that the new metal film resistors have inductive properties, which can induce noise. Most of my customers ask for carbon comp type. I stock mostly 5% carbon new issue type. No reports of failures. As for the 5W stock type, That is as designed by Fender. I am here to repair at low cost due this area. If this were a vintage collectors amp, things would be handled differently. Sorry that you disagree, however I am in this to help out local bands at a reasonable cost plus timing. Remember, I present these videos as reference. Everyone out there has a choice. Thanks for watching
@@d-labelectronics Okay, we will agree to disagree on this one.... -Adrian G from Tone I/O Austin, also doing the same for local musicians :)
Roger that man
@@remley8877 Typical 3 room apt NYC $2700 (Brooklyn)
Nice move putting that resistor on top of the board, saving a lot of time and work.
Fantastic video! What specifically should I order for Caps on my HRD? I'd like to get them ordered before I take the beast apart! I'd rather buy the expensive ones, not sure if they have a part number and who is a supplier...thank you so very much!
D-Lab. How much hum is acceptable? Could you give a peak-to-peak voltage value at the load (load resistor ir speaker) that you would consider acceptable? Also would need the load impedance. I ask this because I bought my first tube amp being a Fender Jr. Even with ALL the tubes removed it has a hum when immediately turned on that I do not know is normal or not. I have a scope and would like to duplicate you output test setup. I do not want to re-cap if not really needed. Thanks. Really enjoy your videos and information.
Also what do you think about re-capping by not removing the circuit board and instead cutting the leads near the cap; remove the bad cap; put the new cap in; and then attaching the new cap leads to the "left standing" old cap leads. You could bend the wires to get a good physical connection and then solder to get a good electrical connection. This is similar to making the decision to solder to the available side of the circuit board instead of spending the time to remove.
Thanks.
I hope D-Lab will provide us with an answer for the first two questions, Fender5621!
Hi Terry, question on the Oscilliscope SIN Wave. you mention which pins you connect to on the output tubes, that you add a resister load to the output in place of a speaker, then you inject the audio signal to the PreAmp is that right? Maybe a short video on the all the setup and tools you use or recommend would useful for some of us. My question is the shape of the SIN diagnosis. When you saw the wave clipped on the up side you immediately said it was a problem with the blah blah. When I used to to Cars and engine diagnosis we used a scope on the spark plug signal and could diagnosis issue based in the shape of that trace of the Spark energy build and drain. It seems you could build up a image video of the various shapes of the SIN wave and what it says to you about the condition or calibration of the tube systems. Am i right in that analogy and could you do such a video for us. I have a scope and am searching for a cheap enough Signal generator then I want to test, measure, diagnose, repair or calibrate all the tube stuff I can get my hands on. I think this would be extremely educational. If you have already done such a video I am sorry i may have missed. let us know where to look. I had seen a video on the operation of a VTVM that explains how it gets its accuracy and thought Wow! that is a great method, balanced signal gets off balance etc etc. Anyway great stuff, thank you so much. I wondered if you get a unknown radio or amplifier could this test be used early on in the discovery to help shape the state or condition of the tube circuits??? D
Hello Dennis, Those sound like good video subjects. Have a back log in the shop right now, but when things slow down I will get something rolling. Appreciate you being part of the D-Lab team. TD
What a great idea to install the resistor on the exposed side of the board instead of pulling it out.
This is a really great video very enlightening on newer Tube gear and what to look for, i now have a tube tester, Scope and searching for that signal generator look out!
Hey Terry, I see that Fender is using those Illinois capacitors on even the newer HRD IV amps. Would you suggest replacing them on sight, or would you let them go until they start causing any noise or hum issues??
Is it normal to have all that hum coming directly from the power tubes? I've never heard anything like that on other tube amps, but I hear it both in this video (even after the other issues are fixed) and on my Hot Rod Deluxe IV
Liked your “ham” T-shirt! Years ago my mom designed a QSL card with much the same design! 😛
I loved this video.And the comments BECAUSE my HRD is doing the same thing.I am putting her on the back burner-too much backlog staring at me.
Funny but on another Amp repair channel he usually replaces bad IC caps with new IC caps
22 year old amp needs new caps obviously of any kind
I use Panasonic or NIchicon (look out for fakes)and in the tube/PCB amps I use High temp
versions,they cost more.
These amp builders could make them last forever with high quality components but then the amp $775 new would be over $1000
One repair and you are defeated
It reminds me of the old days- your friendly TV repair guy would come over and fix your set by simply changing the tubes until the TV worked- didn't even bother to see what the voltages were.The TV would work for 4-5 months,cook the tubes,and he'd be back.
Job security and pathway to a successful shop.Just have a full tube caddy and try not to get zapped.Or shot.
Man, what a great tech! Simplifies a complex process. I have a Hot Rod Deluxe combo, 1-12. Love that amp. It's my go to amp. I love the bottom end it produces and it's got this just wonderful ambience about it that most of my other amps do not have, so I'm always judging the other amps by the sound that the HRD produces. I also have a 22w Super Sonic that does not have that full ambient tone/vibe to it. Do you have any mods or upgrades that you could do to that amp to give it a fuller output tone? I could just send you the chassis. Thanks for the great vid and the bonus tips thrown in!
Thanks for the video first. My Deluxe has two problems. While playing on the low frets -it starts from the 5th or 6th fret of the 6th string- it buzzes. The other problem is the drive button. The clean tone is ok but when I press the drive button the amp hums and buzzes. Also the sound goes down. I can send you videos if you want. I'd be glad if you help me.
Thanks and best wishes.
Hey Terry...how is the reverb tank in a Hot Rod Deluxe fixed or mounted in the back of the amp? Velcro?...screws? The bag is here, there's a cardboard panel in there as well as as the tank itself, but it's free floating around back there...help? Thanks in advance
And oh yeah, loved the "circus board" comments.
Great job, but why did you change that remaining IC filter cab in the preamp also?
All were changed, see last few clips
What do you recommend for a "modern" tube amp? Something that doesn't cook it's own PCB, sounds good, etc? Something affordable would be great too LOL.
Good day ! Please tell me if the timbre knobs, when added, affect the sinusoid(Fender hot rod deluxe) .Thank you
You could also desolder the old resistor and push it out and then shake it out of the chassis. Then you can solder the new one on the solder side of the board like you did. I have done this before on this model amplifier and even some old radios.
Yes, there are many options. This is just an example.
heY Terry, I have a HRD that basically has working just the clean Channel , out of that , no normal, bright, more bright, channel select, or drive on the clean Chanel would work, and overdrive Chanel is completely dead, all filter caps have been switch to F&T's, new resistors raised above the board, I feel a bit lost, any advice will be appreciate it, thanks!
I've noticed a few times throughout videos you've mentioned the poor quality of the Illinois caps. What brands would you recommend for replacement of filter caps?
F&T are great for the cost. Sprague & Mallory are the top pick, but expensive
@@d-labelectronics Hi! I need to recap a vintage fender amp and following the schematic indicates capacitors of 70uf 350v and 20uf 525v, but it is difficult to find those values. I see a lot of folks putting in place the 70uf 350v, 100uf 350v or 80uf 450v. Regarding the value of uf being close to the value of the scheme is ok, but what about the voltage? can add value without problems? in the circuit of bias the schematic asks 25uf 50v. again I see a lot of people putting 100uf 100v. That's right? Is it okay to add these values? in relation to the operation of the equipment, does it change the final tone of the amplifier? I hope you understood my doubt. Thank you for clarifying this.
Hello, Yes, its always fine to exceed the filter cap voltage rating, never go lower. And yes, I use 80's in the place of those 70uf caps. A little more capacitance wont hurt anything. And yes on the negative bias caps, I always increase the capacitance + voltage ratings of the originals. Just make sure to watch polarity! Have fun. TD
@@d-labelectronics Thanks man! I learn a lot here watching your videos! I love seeing the repairs on the old fender amps. See you later!
Agreed, F&T/JJ are good affordable caps... Sprague ATOM is the king. Illinois caps were part of the "cap plague" from 1998-2010... Their current production has remedied the issue, but techs don't forgive.
Another good one Terry, now go have a glass of Robert Mondavi. You have to wonder what fool designed that amp like that. That spinning sound you hear is Leo in his grave. He would never have approved such a poor design. Keep them coming.
Nice job, Terry. Thanks!
Terry, I wouldn't ask except My amp is the exact same animal...
What about the 3rd 22uf electrolytic at the preamp end... ?
Thanx in advance and thanx for another great vid.
cheers
Hello, Yes, I got that one too, you can see it in place further down the vid.
Swap it out as well, and replace the 47uf with a 100uf instead.
Do you ever use an old time tube checker like they use to have in stores way back in the day?
Yep, I have 3 of them here. Amplitrex, Heathkit and B&K. Normally break them out when working on Ham receivers
Excellent video
I just unscrew the mounting screws underneath. 15 min. not 2 hours.
I have the same humming issue on mine (the filter cap when nothing connected). Just curious, is it actually the filter cap making the noise or something underneath it on the other site of the board? I cant seem to locate it myself by listening.
I think mine might need this kind of fix. I don't trust myself to discharge everything properly so probably best taking it to a tech.
Hi, after reaparation amp has a residual hum, what about? Thank You
The IC filter caps . Was it just a batch some years ago or are they still thought to be dubious ?
outlawrickenbacker I've had a few amps through with them in , and all seems well with them , so I believe there was just those bad batches back then . And Mr Carlson recommends their IC poly caps , so I think they are probably a good quality brand .
Hello, not sure if it was a batch issue. I have seen so many bad that I just routinely change them now
Wouldn't it be faster, easier and less expensive to clip the filter caps leaving some leads on each end to use as turrets to install new caps? Similar to how you installed the resistor.
Better to pull the board and resolder questionable solder joints if you have the time. If a customer gets a show wrecked because you were too lazy to pull the board, you will have an angry customer. And word travels fast now-a-days...
Always true... not so much a question of the tech "having the time" but the clients desire and ability to spend the extra money at $30-$50 per hour. In those amps I would say every solder joint is potentially questionable and reflowing them all takes more time and is thus more expensive. Doing the quicker/cheaper job I suggested is in keeping with the method used to replace the resistor so I thought it would be consistent with a $400 amp.
Terry, have you ever converted one of these over to hand wired? If not, would you be willing to take on the task?
I'm not Terry but as far as the actual tube circuit...no problem. It's when you get into ALL of the solid state circuits including the switching, reverb, etc things would get crazy.
John Rapp why? If I like the amp, use it every week, feel that it has paid for itself, have to buy a new one to replace it, why wouldn’t I spend that cash towards a hand wire job?
Actually, I wouldn’t even need the reverb or drive channels. Would like to keep the effects loop though.
Hi, does anyone know how much this type of repair costs?
I think that I need to change mine caps and resistors
I've had a dozen of these over the years with an open 82K resistor.
Strange failure, I wonder if the resistor was under rated (wattage) ?
That would be my guess, Terry.
Why wouldn’t you just undo the screws from the tube socket side? Then the whole PCB assembly comes out without having to remove the main board. Takes all of about 15 minutes to remove and replace the board.
Yeah, that too! It's easy smeegy.
Yes, that could be done. Lots of options to this repair
@@d-labelectronics Sorry Terry... much respect for you and what you do. I just deal with a lot of these, and couldn't help to speak out on this one.
No worries man, always open to options
Yea, I like your shirt. Lol!
Too bad you didn't know you were going to remove the board anyway to replace the caps. Then you wouldn't have to solder the resister on the alternate side of the board.
It was humming because it didn't know the words :)
When resistance is futile you must have the capacitance to endure.... :-)
And the inductance to clear the way.....:-)
Good diagnosis! But if you go to the following web site: www.ampbooks.com/mobile/amplifier-calculators/long-tailed-pair/calculator/ ou will see the 82K/100K pair is not the best way to balance the phase inverter. If you keep the 82K, you can add a 5K or a 10K potentiometer with the B+ going to the wiper and one of the other lugs to the 82K and the other one to the 100K, to balance your inverted and non-inverted phase that feeds the power tubes.