NAD 3020 project, strip down and upgrade.

[Fr1tsie]

Thank you @Mooly. That makes a lot more sense then the diagram I use.
I could not trace the caps on there.
421 and 422 are ceramic caps even on my diagram....

Can you tell me were I can find the diagram you use?

 

[poundy]

220k? 220 ohm

 

[Mooly]

Can you tell me were I can find the diagram you use?

The manual says HiFi Engine on it so it would be from here:

https://www.hifiengine.com/manual_library/nad/3020.shtml

There are so many variations and versions although the one I looked at was just the standard 3020.

 

[Fr1tsie]

@Mooly ah, unfortunatly they closed registrations, so I am not able to download it.

 

[Charm]

Found it on my computer.

 

[poundy]

There are 2 versions of the original series 20 and they have different if simlar schemes

 

[Fr1tsie]

Yes, unfortunatly the schematic I need isnt the one Charm posted. I need the one of the screenshot that Mooly posted.

I have downloaded about 6 schematics, all not the one I need.

@Mooly, if you have the schematic from the screenshot you posted I would be very glad.

You can see the differences of C421 on the diagrams. Second one is that I need.

 

[poundy]

Show me a photo of the inside

 

[poundy]

The yellow circled is a flat disk ceramic tiying the phono ground to case

 

[Fr1tsie]

 

[poundy]

That's the later version

 

[Mooly]

The one I used was this:

 

[poundy]

Did you replace the film caps as well.,they would have been fine. The scheme you need is the one that say 'alt scan' at the end

 

[Fr1tsie]

I am still in the process of recapping. What you see on the picture is an mix between new and old.

 

[Mooly]

The scheme you need is the one that say 'alt scan' at the end

That one would be this:

 

[poundy]

The one I used was this:

View attachment 1146409

View attachment 1146410

View attachment 1146411

If it says alt version at the end it is the right one, it's more like the A version

 

[Mooly]

I've got the 'alt scan' one which looks the same as another I have labelled 'version1 not late'. I'm never clear on which version is which tbh, there are just so many. If the component reference numbers match up it should be the correct version.

 

[poundy]

What is the issue?

 

[poundy]

They look the same but there are differences. The 1ohm on the collector does not exist on the early version and the later version has a cap between the 2 rail supplies. It's clear when you look at it

 

[Mooly]

You really need the amp in front of you to determine what you've got. So many variations on the same basic circuit.