NAD 3020A No sound after changing capacitors.

[Nickaliath]

Hello all,

I have just re-capped a NAD 3020A. It is now decided not to have any sound coming out of it. The red power light illuminates, But that's it.

I am planning to go over all the solder joints tonight, To make sure they are all ok.

Now I changed all the capacitors for the correct replacement, But I want to make sure I haven't made a mistake along the way.

The 3020A circuit diagram is nowhere to be found online.
I wanted to double check all the capacitor values, So I can make sure they have all been fitted in the correct location.

I did try a couple other NAD service manual, But they don't seem to tie up together with this board.

I don't suppose anyone has one or a diagram of the board with capacitor values?

Thanks

[Station X]

An all too familiar story. "I changed ALL the capacitors and now it don't work".

What made you decide to change the capacitors? Did they test faulty? Did you take pictures and make notes?

All water under the bridge now. Check your work and rectify any errors. Are the replacement caps of the right value and fitted the right way round?

If that doesn't work it's time to get your meter out, firstly checking that all power supply voltages are present and correct.

-----

I have a NAD3020 and after 40 years it's starting to hum like a Dansette. When I get a round tuit I'll change the smoothing capacitors and leave everything else well alone.

[G6Tanuki]

Did it work before your recapping-misadventure?

When doing this sort of thing I tend to replace parts one at a time and then check it still works after each part-replacement. OK it adds extra time to the process but does at least make things easier to fault-find when something goes wrong.

[Beobloke]

Did you happen to remove the pre/power links before you started work on it?

If so, did you remember to re-fit them?

[60 oldjohn]

I cut the old component out leaving a short length of wire, that can be trimmed later and test for progress after each component change. Best keep only the current component on the bench if you need to check the value. This was after I got one wire from a capacitor on the adjacent solder tag, robbing me of a raster on a TV. Lucky I had checked after each replacement. This was before the luxury of instant digital photography.

John.

[Nickaliath]

Yeah, I completely agree.

I previously did a cap change on the same type amp, With no issues at all.

Someone I know asked me to take a look at it and sort the sound issue. This was all down to dirty controls and rectified. So it was all working.
However, He asked to do a cap change to make it last longer for the future.

When he hadn't used it for a while, It would take a while till the red light turned on. Which I presume is a cap issue powering up?

I checked all the joints on the solder points and re-flowed them.

I also checked the correct orientation, Corresponding with the board markings.
It appears they all face the same way according to the board.

Sound is coming out, But very quietly.

Originally Posted by Station X

An all too familiar story. "I changed ALL the capacitors and now it don't work".

What made you decide to change the capacitors? Did they test faulty? Did you take pictures and make notes?

All water under the bridge now. Check your work and rectify any errors. Are the replacement caps of the right value and fitted the right way round?

If that doesn't work it's time to get your meter out, firstly checking that all power supply voltages are present and correct.

-----

I have a NAD3020 and after 40 years it's starting to hum like a Dansette. When I get a round tuit I'll change the smoothing capacitors and leave everything else well alone.

[Nickaliath]

Originally Posted by G6Tanuki

Did it work before your recapping-misadventure?

When doing this sort of thing I tend to replace parts one at a time and then check it still works after each part-replacement. OK it adds extra time to the process but does at least make things easier to fault-find when something goes wrong.

Yes, I did exactly that. 1 at a time. I always do it this way.

But I now think I have put one in of an incorrect value, By mistake.

I stupidly didn't make a note as I was removing, Which I now regret.

Wouldn't be so bad if I could find the diagram for the circuit board.

[Nickaliath]

Originally Posted by Beobloke

Did you happen to remove the pre/power links before you started work on it?

If so, did you remember to re-fit them?

Yes, I did. But I put them back in.

[Nickaliath]

Edit: Its a NAD 3020 series 20. Not 3020A

[Beobloke]

Originally Posted by Nickaliath

Yes, I did. But I put them back in.

No worries - just thought I’d double check. We’ve all done it!

Haven’t we….?

[Edward Huggins]

"He asked me to do a cap change" - what kind of nonsense is this? "To make it last longer" - more nonsense. Why be influenced by an Amateur's opinion? In future use your own judgement and carry out the re-working as you see fit. Now, in spite of your best intentions, you could be a long while sorting this.....

[paulsherwin]

As we all know, there is a widespread belief in the HiFi world that equipment needs to be comprehensively recapped every decade or so to maintain the sound quality. If you're doing work for customers then you have to do what they want, no matter how bonkers it is.

[ben]

Unfortunately, there is a whole lot of this capacitor nonsense spouted online, by people with little or no electronics knowledge. They think it's like a car where you have to change the oil every so often or something.

In this case the OP says there is audio but quiet, so I would be injecting a signal at various points to see where the audio is getting cut. And to see if the output stage is at least capable of any oomph.

[paulsherwin]

Personally I suspect this is a switchgear problem and nothing to do with recapping. The 3020 switchgear isn't exactly broadcast quality. It should be easy enough to determine where the signal is getting lost.

Are both channels equally affected?

[jamesperrett]

Originally Posted by ben

Unfortunately, there is a whole lot of this capacitor nonsense spouted online, by people with little or no electronics knowledge.

Sadly this myth is also perpetuated by certain manufacturers nowadays.

Since there is some faint audio getting through I would check the tape monitor switch and also try a buzz test on the power amp inputs.

[Goldie99]

Not sure which circuit this one is, but the headphones socket is a good candidate if it's both channels.

[DMcMahon]

hifiengine.com has various manuals and schematics for the various NAD 3020 models, including schematic for the basic 3020, this does show component values.

David

[Station X]

One post moved to a new thread here:-

https://www.vintage-radio.net/forum/...d.php?t=204126

[Richardgr]

A lot of headshaking over replacing 20 year old electrolytics. Possibly they were 5000 hour rated parts, well beyond their allotted lifespans.

Many years ago I bought a lot of white goods all together, and on queue, at 10 years old, they all packed up one after another. It is reasonable after a certain time period to replaced stressed parts rather than fix issues in an expensive piecemeal way.

[ben]

Originally Posted by Richardgr

A lot of headshaking over replacing 20 year old electrolytics. Possibly they were 5000 hour rated parts, well beyond their allotted lifespans..

Why stop there? Don't forget those 20 year old diodes, resistors, transistors, pots, wire, transformer...

Seriously, I'm all for replacing parts that have drifted in value or otherwise faulty, but blanket changing of parts willy-nilly is absurd, and in this case is what led to the OP's problem. Proper troubleshooting, not a shotgun approach, is what is sadly lacking.