NAD 3020 Switch On Power Thud Sound Issue Repair - Retfurb Retro Audio

In this video we have a NAD 3020 Stereo amplifier, Which has an issue when powering up the unit.
The system has a loud long thud / bang sound, As soon as the power is put through the device.
It is only when turning on the unit and does not happen when powering down.
The system does contain a muting circuit on power up, So hopefully this is all that needs repairing at......
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The NAD 3020 line of amplifiers, Is widely regarded as one of the all time greats. It was a giant killer in the day and still holds its own today.
It is a great sounding amplifier and for the original retail price it is hard to beat.
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Links to our other NAD videos:
NAD 3020A Facia panel refurb - • NAD 3020 A Amplifier F...
NAD 3020A Front control repairs & strip down - • NAD 3020 A Amplifier T...
NAD 3020A Re-Cap • Replacing Old Electrol...
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About Retfurb.
On the channel we will be looking at all things Retro, Vintage & collectable. Along the way we will be carrying out various tasks including; refurbishments, repair, servicing, strip downs, restorations and much more. We aim to bring out new videos at least once a week, But will aim to release new videos more regularly.
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Retfurb
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Warning
All of our videos are intended for entertainment purposes only.
Any tasks we show on our videos, should be carried out by qualified persons only. All of the repairs, refurbs, modifications, etc can be hazardous to health. We ensure all safety precautions are carried out first, Before attempting any repairs.
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Music made using: Bandlab

[@humoursque8447]

5:46 For those who are not technician changing capacitors and soldering. Get yourself a headphone plug. Plugged it in then switch on. You won't hear any thuds. Complete silence.Leave it in for few seconds then remove same. You can play the amplifier as normal. Ideally if you can change the capacitors by all means.

[@retfurb]

Yeah, that is a very good tip. Thank you for adding this. It essentially blocks the signal to the speakers, acting as a manual mute. 👍🏻👍🏻

[@don7680]

Thanks! C531, C532 & C533. Replace with 47uF / 63 volt caps.

[@retfurb]

This is what was recommended on this particular model of the 3020. As said in the video, each amplifier manual needs checking. Just to make sure it is correct for the NAD in question. 👍🏻👍🏻

[@LaughingDolphin]

Got the same problem with my 3040 PE

[@gillanland]

Would've been nice to show the schematic and try to explain what causes such a behavior of amplifier, but thank you anyway !

[@retfurb]

Yes, I should have at least explained the muting circuit more. I was trying to keep the video shorter, so that was my fault.

[@FrankJCarver]

Nice repair. Weird noises through the speaker are a pain. I have a Sony CD, cassette recorder, which was dead, but I have got working, but I have this annoying thud that comes when I turn it off and when I press the cassette player button. Do you think it could also be a bad cap?

[@retfurb]

Thank you, it’s appreciate. Ah, good work. Always nice to get things working again. To be honest, it’s hard to say without looking at it. Could possibly be or something relating to the switched components maybe.

[@FrankJCarver]

@@retfurb Thank you.

[@blipco5]

I wouldn’t change that cool startup effect. In fact I’d pay extra for that option.

[@blipco5]

In fact it sounds like the intro to Butt Hole Surfers "Pepper". 👍

[@retfurb]

Does sound different, but not normal. I don’t think the speakers would thank me, if left with the issue. 🙂

[@blipco5]

@@retfurb I make joke. But look up "Pepper" by BH Surfers.

[@TechGorilla1987]

I had a nice set of NADs back in the day. I rather like the minimalist look.

[@retfurb]

100% agree.

[@TechGorilla1987]

@@retfurb I was also trying to make a cheeky joke :D That said, I did have this model and I believe I had the 1020 preamp which I fed to a big 'ol Hafler amp. Used it to DJ for the Parents Without Partners group here in the states

[@retfurb]

@@TechGorilla1987 Ha, you never know when NAD is talked about. Although I did have someone on a different video, tell me it’s N.A.D and not NAD. 😃

[@TechGorilla1987]

@@retfurb Yeah, life is too short to be that uptight. Stay well, my friend!

[@retfurb]

@@TechGorilla1987 you too 👍🏻

[@stevesmith3990]

Interesting. I have one exactly the same that has been fully restored and recapped. It has a bit of a thump when switching on but not really a problem. I read somewhere that its because the output should be muted for the first 10 seconds which wasn't included in the circuit on these models? Not sure if that's correct or whether mine still has a problem as you were able to completely silence that one. Thanks for the video.

[@retfurb]

I think there are some differences. I have fully recapped others and still had a small hum / thud at start up. This is apparently completely normal and happened on some from new. Its always better to power on with volume muted. This was different from any others I listened to, Apart from one other that was similar. This method fixed that one also, That is why I was sure it would be this.

[@PerilousPaddy]

That's less of a thud and more of a robot farting, my 3020 always thud when turning it on and I just had to make sure the volume was turned all the way down before power up made it bare able.

[@retfurb]

🤣🤣 that’s one way to put it. Yeah, I’ve heard others with a slight thud, but this was different. It still did it regardless of volume position.