Thanks for uploading this video. Repaired and recapped 3 NAD integrated amps with same problem, bad caps. All amps I restored only 5 to 10 years with same leaky caps and blown caps problem, because NAD used very cheap caps. Their receiver even worse. NAD fanboy would say "It's all about sound, it's OK if quality of their amp is not good", what??
Just repaired one of these amps for a friend. It had exactly the same symptoms and would power up from orange to blue only after heating the same micro controller chip (IC101). Further investigations revealed the fault cause to be C1039 (10uf 16v electrolytic), proved by carefully thermally isolating and heating said component on-board and then off-board connected via fly leads. C1039 replaced with standard (not SMD) 10uf 35v electrolytic and all’s now hunky dory. This capacitor forms part of the micro controller's reset circuitry, in my case locking micro controller pin25 (reset) in reset state. I hope this helps others as this problem seems to be a fairly common issue with these amps.
@@limtk55 Just rechecked my service manual. It’s definitely C1039 that I replaced, POR hold down cap. My friend’s amp is still going strong. I suggest you locate the correct schematic diagram version for your amp. Oh and by the way your unwarranted sarcasm is noted!
I have this same problem and identified that surface mounted capacitor. I’ve seen several ways to take the capacitor off including twisting. Some say it depends on how big the capacitor is. Can I ask which approach you took. Thanks
Mines a year old. This concerns me. No issues yet but I've already had a Pioneer Elite whose subwoofer out quit working. Have a Marantz NR1504 in the basement and it seems a good solid little unit
Hi there thanks excellent video. I have the t747. Everything comes on normal but no sound. Could this be the protective cct on pre amp as shown in your previous video? Cheers from south africa
If the microprocessor is the problem with this unit, and heating it up makes it seem to come to life again, I strongly recommend checking if the *clock signal is present* . It could be as simple as that. Given the poor choice of components, I woudn't be surprised if a *dodgy crystal oscillator* (hint, hint) were the cause of that.
I just checked the crystal, and it does seem to make a difference on the operation of the unit if it's heated. However, once it's warm it runs just fine, and even in that state the unit does not work properly. It just sticks in the permanently powered on state. It's as if the µc fails to toggle between its powered on and powered off states.
Bummer! BTW, have you checked if there's anything suspicious about the reset signal to the microcontroller? Or even some instability on the +5V power rail -- some micros are very picky about supply voltages.
I had an NAD receiver (AV760?) from the early 90s, as well as an NAD 5000 CD player. Both are long dead. The receiver had its final drive transistors and their base drive resistors replaced once (no, I didn't push it very hard), but it failed again and wasn't repairable the second time. The CD player suddenly lost the ability to play CDs without horrible skipping. I tore down the receiver, sold its large transformer on eBay and put some odds and ends in my parts bin. The CD player is in a box somewhere awaiting the same fate. I have a Yamaha receiver now that's been chugging along reliably for years. After seeing how the NAD receiver was built and performed, I'd never buy another one!
I found your video interesting and if you monitor your comments I was wondering if you've ever seen an issue with T787 that was working perfect and essentially new, not used for awhile and then when it's powered up and turns on the light turns blue, there's a click, the display reads T787, but seconds later it clicks again, and light turns amber going into standby, but display stays on. Problem is repeatedly the same with no change.
Hi, My NAD C356BEE amplifier makes continues clicking noise and standby light starts blinking on power switch when I try to switch ON'. Also it keeps on standby mode for long time. Before it happens some times but now it comes more often. Some times it gets power ON' and keeps running without no issue till power OFF'. I am looking for a solution to fix this. Please help me to resolve this issue!.
Hi , I have some issue on mine T748 main electrical board Do you selling any main electric board for T748 ? Or you have any seller that can introduce to me Thank you ☺️
Might be something like the crystal not oscillating properly.. Once had that on a receiver causing the cpu to do crazy stuff like not responding anymore.
Heating the IC that much to get it working again is odd. Is it fixing a bad connection (bad solder joint, dislodged bond wire inside the IC package), or is it causing a failed part to shut down (eg a shorted GPIO pin/bus). Debugging with those tiny pin packages is a nightmare, so even checking for IO lines shorted to the positive rail or ground, is going to be a pain.
I'm sitting on a T747 which shuts off almost immediately after powering on and now I'm wondering if it isn't a processor issue as well. The 747 is far more densely packed than the 784 and I have no intention of taking it apart. I'll probably just donate it or sell it for parts.
I have the exact same model. My problem is that it has the stanby light (orange), turns on fine. But shortly after it turns off going into power saving, only used it once.
Yet my NAD 3020 amp just keeps on going... 35 years old. All original parts, except for banana plug speaker sockets, and a green LED. My NAD 514 CD player sometimes needs percussive maintenance to get it to accept a CD though... ;o)
I have the 3120. Recently replaced the main filter caps and installed an 80mm fan to cool it down (nothing major, it's just held on to the top cover using small zip ties). I would recommend doing the same to yours as these are starting to get quite old. Sounds brilliant though.
I had similar strange issues with other equipment unrelated to audio and this helped to eliminate these problems very well. The momentary switches get cheaper and cheaper made, they really suck today. Don't even work for more than 2 years without developing major bouncing.
thanks for the video...I have the same issue with mine...can only turn the reciever off by pulling the power cord....did you eventualy sort out the problem..?? Thanks..!!
Great video! In your repair of receivers, which one seems to have good quality internals? Like any particular brand or model? I was gonna buy NAD to replace my Pioneer Elite (still works but getting old), and I am now not sure if it's a good investment. Have you ever opened up a Marantz, Anthem or Arcam receivers?
I agree with you on the component quality but you haven't worked on earlier -00 Nad models, they used to have Elna, Nichicons and Rubycon caps.. Alps pots and switches and so on... For example a Nad receiver AV316 from 1995 had Nichicon Gold Tune caps in it... what you're dealing with here and must been dealing with before is the Lenbrook era Nad products. I think it was around 2000 they got bought up by Lenbrook Divisions in Canada. After that everything went kinda haywire. Think the new Nad don't even sound good. Been reparing and owning lots of NAD and seems nowadays they just wanna make money. They're not worth it anymore.
Do you still reply this comment section? My NAD NAD T748 is not turning on. Instead, an ORANGE led appears and nothing else. I’ve tried everything: removing the power cabe and waiting for 10 minutes, plugging to another power plug, but nothing works. Can you help?
You cannot replace it. It's a custom programmed part. Code for the chip is not available to the public, and usually you cannot read out the code of the old chip as it's locked down.
It's not your failure, it's what i would call "Using a cpu to turn a led on.", overcomplex control system for a stupidly simple job. That's the reason i don't like programmed processors/pic/atmel/other, if they die, then it's all dead!!.:-(. The pins on that processor are 100% soldered down, yep yep ok silly question lol.
zx8401ztv Yeah, NAD uses chinese capacitors too which have been known to blow up. But this is consumer equipment. You can't expect it to be as reliable as you are thinking it should be. XD
zx8401ztv jup seems that quality has gone down my nad 7020 and my nad 3400 still work fine and sound incredible. But hey don't all audio products now days suck?
Don't buy NAD they are mafia fucking crappy. They arrange amp so they heat too much and those processors always burn to death. Today's amp are all crap. Companies just think of one thing, make MONEY. STEEL PEOPLE. They deserve to go to jail. I hate today's world. Just buy vintage, good old vintage. The only thing that count today is MONEY, pffff... shame on you NAD.......I had to fix a nad t761 first time that heat too much and i did replace the output transistors and 4 months after the customer came back to me with a dead processor. SHAME ON NAD! And same thing for PIONNER AND A LOT OF OTHERS.
Thanks for uploading this video. Repaired and recapped 3 NAD integrated amps with same problem, bad caps. All amps I restored only 5 to 10 years with same leaky caps and blown caps problem, because NAD used very cheap caps. Their receiver even worse. NAD fanboy would say "It's all about sound, it's OK if quality of their amp is not good", what??
like all modern cpu based appliances,7 years and they are gone,very well thought out
Just repaired one of these amps for a friend. It had exactly the same symptoms and would power up from orange to blue only after heating the same micro controller chip (IC101). Further investigations revealed the fault cause to be C1039 (10uf 16v electrolytic), proved by carefully thermally isolating and heating said component on-board and then off-board connected via fly leads. C1039 replaced with standard (not SMD) 10uf 35v electrolytic and all’s now hunky dory. This capacitor forms part of the micro controller's reset circuitry, in my case locking micro controller pin25 (reset) in reset state. I hope this helps others as this problem seems to be a fairly common issue with these amps.
Please make a video about it. It would save a lot of people s loy of money.
please bro
Oh, and I suppose you haven't noticed the Service manual does not contain a capacitor named part C1039?
@@limtk55 Just rechecked my service manual. It’s definitely C1039 that I replaced, POR hold down cap. My friend’s amp is still going strong. I suggest you locate the correct schematic diagram version for your amp. Oh and by the way your unwarranted sarcasm is noted!
I have this same problem and identified that surface mounted capacitor. I’ve seen several ways to take the capacitor off including twisting. Some say it depends on how big the capacitor is. Can I ask which approach you took. Thanks
Mines a year old. This concerns me. No issues yet but I've already had a Pioneer Elite whose subwoofer out quit working. Have a Marantz NR1504 in the basement and it seems a good solid little unit
Hi there thanks excellent video.
I have the t747. Everything comes on normal but no sound. Could this be the protective cct on pre amp as shown in your previous video?
Cheers from south africa
If the microprocessor is the problem with this unit, and heating it up makes it seem to come to life again, I strongly recommend checking if the *clock signal is present* . It could be as simple as that.
Given the poor choice of components, I woudn't be surprised if a *dodgy crystal oscillator* (hint, hint) were the cause of that.
I just checked the crystal, and it does seem to make a difference on the operation of the unit if it's heated. However, once it's warm it runs just fine, and even in that state the unit does not work properly. It just sticks in the permanently powered on state. It's as if the µc fails to toggle between its powered on and powered off states.
Bummer! BTW, have you checked if there's anything suspicious about the reset signal to the microcontroller? Or even some instability on the +5V power rail -- some micros are very picky about supply voltages.
I'll stay with my mid '70s Harmon/Kardon 430. It just works
I had an NAD receiver (AV760?) from the early 90s, as well as an NAD 5000 CD player. Both are long dead. The receiver had its final drive transistors and their base drive resistors replaced once (no, I didn't push it very hard), but it failed again and wasn't repairable the second time. The CD player suddenly lost the ability to play CDs without horrible skipping.
I tore down the receiver, sold its large transformer on eBay and put some odds and ends in my parts bin. The CD player is in a box somewhere awaiting the same fate.
I have a Yamaha receiver now that's been chugging along reliably for years. After seeing how the NAD receiver was built and performed, I'd never buy another one!
I found your video interesting and if you monitor your comments I was wondering if you've ever seen an issue with T787 that was working perfect and essentially new, not used for awhile and then when it's powered up and turns on the light turns blue, there's a click, the display reads T787, but seconds later it clicks again, and light turns amber going into standby, but display stays on. Problem is repeatedly the same with no change.
Todd, did you manage to fix this issue? How? I have the exact same symptoms : (
NAD T748 is in standby condition and we have replaced the condenser and it can appear but the buttons don't work yet, can we help, thank you
Hi, My NAD C356BEE amplifier makes continues clicking noise and standby light starts blinking on power switch when I try to switch ON'. Also it keeps on standby mode for long time. Before it happens some times but now it comes more often. Some times it gets power ON' and keeps running without no issue till power OFF'. I am looking for a solution to fix this. Please help me to resolve this issue!.
Hi , I have some issue on mine T748 main electrical board
Do you selling any main electric board for T748 ? Or you have any seller that can introduce to me
Thank you ☺️
Might be something like the crystal not oscillating properly.. Once had that on a receiver causing the cpu to do crazy stuff like not responding anymore.
There could always be a thousand reasons for anything. Sadly, eliminating every single one doesn't warrant the effort.
Good point worth swapping xstal, but heating is odd.
Heating the IC that much to get it working again is odd. Is it fixing a bad connection (bad solder joint, dislodged bond wire inside the IC package), or is it causing a failed part to shut down (eg a shorted GPIO pin/bus).
Debugging with those tiny pin packages is a nightmare, so even checking for IO lines shorted to the positive rail or ground, is going to be a pain.
looks like nicely laid out boards and someone went on it with "make it cheap" hammer :)
I'm sitting on a T747 which shuts off almost immediately after powering on and now I'm wondering if it isn't a processor issue as well. The 747 is far more densely packed than the 784 and I have no intention of taking it apart. I'll probably just donate it or sell it for parts.
Dc offset or bias current?
I have the exact same model. My problem is that it has the stanby light (orange), turns on fine.
But shortly after it turns off going into power saving, only used it once.
Yet my NAD 3020 amp just keeps on going... 35 years old. All original parts, except for banana plug speaker sockets, and a green LED.
My NAD 514 CD player sometimes needs percussive maintenance to get it to accept a CD though... ;o)
I have the 3120. Recently replaced the main filter caps and installed an 80mm fan to cool it down (nothing major, it's just held on to the top cover using small zip ties). I would recommend doing the same to yours as these are starting to get quite old. Sounds brilliant though.
Ahh a real NAD, the 3020 was made by the real company, NAD was sold off later on, just a name now :(
Did you try a debouncing circuit for that WKUP pin?
No, failure of such a circuit sounds quite unlikely.
I had similar strange issues with other equipment unrelated to audio and this helped to eliminate these problems very well. The momentary switches get cheaper and cheaper made, they really suck today. Don't even work for more than 2 years without developing major bouncing.
The power button was not connected to that.
Thanks for sharing nice video, have the same issue with my Nad T747, to bad with the poor quality
thanks for the video...I have the same issue with mine...can only turn the reciever off by pulling the power cord....did you eventualy sort out the problem..?? Thanks..!!
No, I just turned it analogue.
Great video! In your repair of receivers, which one seems to have good quality internals? Like any particular brand or model? I was gonna buy NAD to replace my Pioneer Elite (still works but getting old), and I am now not sure if it's a good investment. Have you ever opened up a Marantz, Anthem or Arcam receivers?
Yep, all of them. Arcam are trash. Absolute trash. The rest are about the same. They all eat HDMI boards after 4 years.
FFcossag thanks. wow. I thought Arcam could be best. So between NAD and Anthem, which do you like better?
I had an anthem. Died after 6 years. Just got this NAD hoping for a better result, but this doesn’t make me too optimistic
My T778 just had a similar issue.It wont power on.i dont have the same wont power off issue,as mine wont power on
Hi, If you are still trying to fix this issue you may want to look at my post of earlier today.
Does the microprocessor have a serial or jtag interface that you could debug?
Maybe, but it's not worth the effort.
Even if it did, it will be completely undocumented, so what's the use?
I agree with you on the component quality but you haven't worked on earlier -00 Nad models, they used to have Elna, Nichicons and Rubycon caps.. Alps pots and switches and so on... For example a Nad receiver AV316 from 1995 had Nichicon Gold Tune caps in it... what you're dealing with here and must been dealing with before is the Lenbrook era Nad products. I think it was around 2000 they got bought up by Lenbrook Divisions in Canada. After that everything went kinda haywire. Think the new Nad don't even sound good. Been reparing and owning lots of NAD and seems nowadays they just wanna make money. They're not worth it anymore.
Do you still reply this comment section? My NAD NAD T748 is not turning on. Instead, an ORANGE led appears and nothing else. I’ve tried everything: removing the power cabe and waiting for 10 minutes, plugging to another power plug, but nothing works. Can you help?
Afraid not, the unit in this video is the only one of these I've ever worked on.
Mine hoes on Amp PROTECTION mode when I turn it on
Hi, If you're still looking to fix your amp you may want to take a look at my comment post of today.
@@petcatznz Thank you so much. I´ll definitely try it!
Short relay on, and use a wireless mains switch?? 5 watt resistor on Uproc as heater, lol.
Sadly, the device doesn't work at all when the processor fails to boot.
I see, save the finals 2sd...
Heatsinks on CPUs, they're useful... :P
Perhaps re-flowing the chip would have fixed the issue.
When we're in the process of bashing the construction of this amp, they are also using that EVIL glue that turns conductive over time :/
Yes, I forgot to point that out.
Too bad the cost vs value ratio doesn't warrent replacing the chip.
You cannot replace it. It's a custom programmed part. Code for the chip is not available to the public, and usually you cannot read out the code of the old chip as it's locked down.
I have same problem and same model.
Where u from I only used my amp once and it died
Which NAD in the past has good caps? when did this CHEAP crap start going into NAD ?
It's not your failure, it's what i would call "Using a cpu to turn a led on.", overcomplex control system for a stupidly simple job.
That's the reason i don't like programmed processors/pic/atmel/other, if they die, then it's all dead!!.:-(.
The pins on that processor are 100% soldered down, yep yep ok silly question lol.
It's fine from a systems engineering standpoint. They need the processor to do other stuff anyway.
I still dont like the death of a unit for just one chip :-(.
NAD was good in the 1970's, not the same company now :-(
zx8401ztv
Yeah, NAD uses chinese capacitors too which have been known to blow up.
But this is consumer equipment. You can't expect it to be as reliable as you are thinking it should be. XD
zx8401ztv jup seems that quality has gone down my nad 7020 and my nad 3400 still work fine and sound incredible. But hey don't all audio products now days suck?
i have the same problem - i just found the service manual for this amplifier in pdf with circuit diagrams, etc. if anyone needs
Yes I need circuit diagrams for NAD T747, can you sent to me on: schrempfivica@gmail.com, thank you in advance
id love please
I remember, you were unemployed weren't you?
It varies.
Don't buy NAD they are mafia fucking crappy. They arrange amp so they heat too much and those processors always burn to death. Today's amp are all crap. Companies just think of one thing, make MONEY. STEEL PEOPLE. They deserve to go to jail. I hate today's world. Just buy vintage, good old vintage. The only thing that count today is MONEY, pffff... shame on you NAD.......I had to fix a nad t761 first time that heat too much and i did replace the output transistors and 4 months after the customer came back to me with a dead processor. SHAME ON NAD! And same thing for PIONNER AND A LOT OF OTHERS.
Token comment to stop anyone from saying first.
I 'second' that