NAD 3020 A Amplifier Tone Control Sound Issue Fault Finding & Repair. Retfurb Retro Audio
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- Опубліковано 22 сер 2024
- In this video we take a look at a vintage 1980's NAD 3020A stereo amplifier. This unit has an issue with sound on the tone controls. We will disassemble the unit, to allow access to the components. We can then fault find the issues and repair or replace what is required. This should then hopefully rectify the problems.
The components on these NAD amplifiers, Are not the highest quality. They can commonly develop a fault and Unfortunately a lot of the parts are hard to find.
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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.
This particular amplifier was purchased recently with the issue, In the hope it can be restored back to the former condition.
These NAD amplifiers are very collectible, So it is worth keeping them from going to scrap..
Here is the link to the front fascia panel refurbish
• NAD 3020 A Amplifier F...
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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, servicing, strip downs 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: Night Rider by JIGLR is licensed under a Creative Commons License.
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First time seeing someone repair a potentiometer with glue and conductive paint, didn't even think of that :D I would have replaced the volume pot with a matching Alps or something like that, but you have certainly put in the effort to keep it original.
😀I thought it was definitely worth a shot. The worse thing that could have happened, Would be that they still were not working.
Admittedly, They probably are not as accurate as they once were. But it is a low cost repair and keeps the unit going. 👍
Good job, can you perhaps make a video on how you painted the titles on the refurbished faceplace. I have repaired many NAD 3020s and own a couple of them. I can give you some guidance on the delay and balance control. Firstly, NAD 3020s dont have speaker relays, instead they have a delay circuit wired between the preamplifier stages and power amplifier stages. This circuit features a single FET, J111 for each channel. if this circuit fails, you will have that startup hum and delay on switch on. You can trace the fault in this stage and rectify it or simply remove the FET for each channel and bypass the signal path. The amp will start up immediately when you power up and the startup hum will also disappear. Now to the balance control. Its a simple fix. Assuming that you have checked the balance POT itself with a multimeter, listen carefull to your amp play, especially if you use headphones. If your amp does not give you stereo sound and the music seems to be appearing from between the speakers or at the center on your headphones, that will mean that the shaft (center pin on the POT) is not grounded due to a break in the PCB. You will have to trace continuity on the PCB and locate the break. If this is not the fault, then you have to check the two outer pins of the POT and the connectivity with each channel. Place one of your multimeter's probes on the left channel U-connector (Preamp to poweramp) on the back panel of the amp and the other on the outer pin of the balance control which points to the left side, repeat with the other u-connector (right channel and the right side outer pin of the POT. You should get connectivity. If you dont, you'll have to tracel the PCB tracks and find out the break-points. All the very best.
Thank you for that comprehensive write up. That is some very good information. I love this, As it will also help others.
With regards to the faceplate, I do have a separate video for this you ua-cam.com/video/FLm_cVbT7-c/v-deo.htmlsi=M241-tda75ESkTWR
Bypass the tone controls then you will have one of the best amps evee made even better, FYI this is holds the record for the most sales of any amplifier ever made.
I was going to do this and make a custom front panel. However, It wasn't as straight forward when I looked in to it. This is from the research I did online.
Although I did think it could be replaced with resistors of the same resistance, when it is in the middle position?
i suggest you retain the tone controls, keep them locked in flat (center position) and you will be fine. The tone controls and loudness control can come in very handy at times, good to have them 🙂
Great video. I have NAD 302 version, the light is on but can only hear extremely low sound if I crack the volume to the max. Can you suggest anything i can try?
Thanks a lot.
Thank you. The first thing I would always try on these, Is to deoxit all the control potentiometers. I have got another NAD video coming soon and almost all issues were down to dirty pots. Its the first place to start.
Assuming you have the same symptoms for all your inputs and again assuming you have checked all your input interconnects wired to your amp, it is definitely that your amp's selector switching is faulty or clogged, use deoxit on the selector switches (inside) and you will be fine. Also check if the u-connectors on the back of the amp, which connect the preamp to poweramp are in place and making good contact.