Beautiful amp. Love NAD. Just picked up a mint 7020e receiver the other day which I'm planning on restoring electrically. Might do a full recap video for my channel.
I bought one of these new about 20 years ago. After a few short weeks it started going into protect mode as soon as I switched it on. There was a lot going on in my life at the time so I never got it back to the retailer for a repair under warranty. I believe that going into protect mode was a common problem and that NAD proposed a fix at the time, but I never got hold of the parts or the service bulletin that described the fix. There is a brief note at the back of the service manual that I found online but I find the note too ambiguous to use. BUT after all these years I am going to start investigating and see if I can bring the amp to life. First stop is to get hold of all the information I can find online about these amps. I have minimal electronics experience but I am going to tread carefully and bear in mind that a little knowledge is a dangerous thing...
Cover the case vents an leave it under load and I'll wager you'll replicate the issue. As you mentioned NAD amps of this era run at high current with barely sufficient heatsinks. They need to breathe. Thanks for the vid Trevor.
I doubt it because the glitch would happen at random, hot or cold. Some days it would glitch once, some days it wouldn't glitch. I ran the amp for several weeks to see if I could figure out what triggers it with no conclusion
I'd have started with the momentary contact switches. They're usually wired in series with resistors, and the microcontroller determines which button has been pressed by the value of the total resistance in the circuit. If 1 switch is bad / dirty, it makes the amp do all kinds of weird things.
My c326bee is not playing at all in the right channel, when used as a pre-amp. If I use it by itself, the sound is weak and gritty in the right channel. Took the cover off, seeing the top on one of the big capacitors on the power supply is bulky. Any ideas towards this could cause the sound problem nor is it something related?
It's likely a dead capacitor or cracked solder joints. Would need to be on the bench to troubleshoot but you can look for yourself for cracked solders. If it's high hours unit there will be heat zones identified by darkened areas. Look in these zones for crusty looking solder joints. If you have the tools and talent, you can re-solder any that look bad. The big capacitors are for both channels so if the left is working fine, that rules it out
Hi Luke, good question. I use Hifiengine and Vinylengine a lot. If I can't find my fix there I also use elektrotanya.com/keres I know of a few others but I lost the links when my computer crashed. I'd be interested in learning more if anybody else knows some
Hi Trevor. Just wondering if this story has happy end. I have the similar issue with 326BEE. It turns off intermittently. However, no switching inputs so far.
Hi Trevor. I recently pulled my 326 out of storage to setup as power amp only, connected to a preamp. The power amp works fine but now the preamp does not work at all. It worked when I put it in storage. I don’t know what happened. Anyway, do you do repairs on the side for these? Or can you point me to someone who does? Thanks
Dear Trevor, with reference to Episode nr136 and the work that you have done on the Nad C326. Did you manage to fix the problem as you did not post an update on the issue yet? Would be interesting to get follow up feedback on the issue since this video? Thanks in advance!
Crap Trevor, I just took a 326 in trade for service work. Let's see what the interweb has to say...Oh yeah this is the one Trevor videoed and is notorious for buggy faults. As always thanks for your enjoyable vids.
I've repaired more than my fair share of NAD amps and the biggest problem I have found by far are bad caps. NAD went through a stage of using cheap chinese rubbish and even caps that test ok have been shown to be bad. That blue one under the front panel board (below the added red cap) should be removed as it's likely to be bad and will negate any positive effect of the added cap.
I agree. The quality of caps NAD used is shameful. They used cheap quality caps only rated for 85C and they didn't last long in the hostile environment. In this amp I only replaced the failed caps in the heat zones. I left the others alone since they tested fine
@@puciohenzap891 In my humble opinion and experience only the electrolytic caps are of bad quality. Otherwise the rest of the parts are very decent and coupled to Nad's very good overall design geared towards high current output stages. The bad JH caps are found in mostly the newer generation models. Replace them and you will have a very solid and reliable amp (and good sounding).
Beautiful amp. Love NAD. Just picked up a mint 7020e receiver the other day which I'm planning on restoring electrically. Might do a full recap video for my channel.
I'd like to see that if you're up to it
I bought one of these new about 20 years ago. After a few short weeks it started going into protect mode as soon as I switched it on. There was a lot going on in my life at the time so I never got it back to the retailer for a repair under warranty. I believe that going into protect mode was a common problem and that NAD proposed a fix at the time, but I never got hold of the parts or the service bulletin that described the fix. There is a brief note at the back of the service manual that I found online but I find the note too ambiguous to use. BUT after all these years I am going to start investigating and see if I can bring the amp to life. First stop is to get hold of all the information I can find online about these amps. I have minimal electronics experience but I am going to tread carefully and bear in mind that a little knowledge is a dangerous thing...
Sometimes they drive you nuts! Thank you for the video.
hi Trevor, thanks for the video, looking forward to the next one ;-)
Cover the case vents an leave it under load and I'll wager you'll replicate the issue. As you mentioned NAD amps of this era run at high current with barely sufficient heatsinks. They need to breathe. Thanks for the vid Trevor.
I doubt it because the glitch would happen at random, hot or cold. Some days it would glitch once, some days it wouldn't glitch. I ran the amp for several weeks to see if I could figure out what triggers it with no conclusion
@@TrevorsBench mine does exactly the same
I'd have started with the momentary contact switches. They're usually wired in series with resistors, and the microcontroller determines which button has been pressed by the value of the total resistance in the circuit. If 1 switch is bad / dirty, it makes the amp do all kinds of weird things.
Hi I have sent you a direct mail with the 3 factory modification service bulletins and the service manual for the auto standby version.
My c326bee is not playing at all in the right channel, when used as a pre-amp. If I use it by itself, the sound is weak and gritty in the right channel.
Took the cover off, seeing the top on one of the big capacitors on the power supply is bulky. Any ideas towards this could cause the sound problem nor is it something related?
It's likely a dead capacitor or cracked solder joints. Would need to be on the bench to troubleshoot but you can look for yourself for cracked solders. If it's high hours unit there will be heat zones identified by darkened areas. Look in these zones for crusty looking solder joints. If you have the tools and talent, you can re-solder any that look bad.
The big capacitors are for both channels so if the left is working fine, that rules it out
Take out those JH capacitors and throw em' in the junk.
Hi Trevor ,hi, please, do you have a good website for downloading schematics? Somewhere where almost everything is? Thank you very much 😇😊
Hi Luke, good question. I use Hifiengine and Vinylengine a lot. If I can't find my fix there I also use elektrotanya.com/keres
I know of a few others but I lost the links when my computer crashed. I'd be interested in learning more if anybody else knows some
@@TrevorsBench Hello, you are sweet, thank you very much, and then take care :-)
Hi Trevor. Just wondering if this story has happy end. I have the similar issue with 326BEE. It turns off intermittently. However, no switching inputs so far.
I've tested this amp a few times and so far it's behaved
Can you advise please, which caps to replace on this amp, except those biggest, to give it new life or even better sound?
Hi Trevor. I recently pulled my 326 out of storage to setup as power amp only, connected to a preamp. The power amp works fine but now the preamp does not work at all. It worked when I put it in storage. I don’t know what happened. Anyway, do you do repairs on the side for these? Or can you point me to someone who does? Thanks
I have a 356bee that turned off, standby light went out too.
Main fuse OK, +5V OK, standby voltage +2.6V - is it correct?
Dear Trevor, with reference to Episode nr136 and the work that you have done on the Nad C326. Did you manage to fix the problem as you did not post an update on the issue yet? Would be interesting to get follow up feedback on the issue since this video? Thanks in advance!
I tested the amplifier for about 2 - 3 weeks of use and the problem never re-occured.
@@TrevorsBench Thank you very much. That's great to here. And thanks for a very informative channel.
I just restored a NAD C356BEE full of those junk JH Capacitors. Mains caps are 22,000uF.
I have this amp. Does anyone know where the fuses are located.
If all else fails, might re flow U503.
Crap Trevor, I just took a 326 in trade for service work. Let's see what the interweb has to say...Oh yeah this is the one Trevor videoed and is notorious for buggy faults. As always thanks for your enjoyable vids.
Hope the video is useful for you. Thanks!
I've repaired more than my fair share of NAD amps and the biggest problem I have found by far are bad caps. NAD went through a stage of using cheap chinese rubbish and even caps that test ok have been shown to be bad. That blue one under the front panel board (below the added red cap) should be removed as it's likely to be bad and will negate any positive effect of the added cap.
I agree. The quality of caps NAD used is shameful. They used cheap quality caps only rated for 85C and they didn't last long in the hostile environment. In this amp I only replaced the failed caps in the heat zones. I left the others alone since they tested fine
Seen many NADs aswell and NAD is built to fail after the warranty expires. Not only bad caps but overall bad, failing designs with underspec parts.
@@puciohenzap891 In my humble opinion and experience only the electrolytic caps are of bad quality. Otherwise the rest of the parts are very decent and coupled to Nad's very good overall design geared towards high current output stages. The bad JH caps are found in mostly the newer generation models. Replace them and you will have a very solid and reliable amp (and good sounding).
Would you be interested in restoring my dads reel to reel decks?
I'm trying to avoid outside work right now because I'm quite busy with repairs and life stuff. Perhaps later or in 2023.
@@TrevorsBench okay i understand. Thank you 🤙