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NAD 1020 Preamp Recap Parts List

G

Gansett

New Member
Hi,

I'm looking to recap an old NAD 1020. Just wanted to see if anyone here had a parts list to make it easy. I'm pretty much a noob at this. I can use the soldering iron and match up values, but that is about the extent of it. I've read that one should use low leakage caps for caps in the audio signal, but have no idea which ones are in the signal and which aren't. Any help would be greatly appreciated. Not looking to steal anyone's list here. I know Leesonic has experience with these and has a proprietary list that he understandably keeps to himself. I'm just looking for a basic recap/restore to make this sound better. Thanks in advance. I've attached the schematic (that i have no idea how to read) and the cap list.
1020b schematic.png nad 1020 caps.png
 
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The signal path is indicated by the bold line. I have been using nice audio caps (Nichicon UKZ/UFG) for everything except the power supply... and then UPW there... But I'm pretty new, so low leakage in the signal path may be better.
 
Thanks for the reply. That is helpful. So assuming the signal path is the bold line, and making some educated guesses, the signal path caps are C401/402, C505/506, C507/508, C519/520, and C305/306 (highlighted on the attachment). I'd just buy low leakage caps for those?

signal path.GIF

For the PSU I've also read to use low ESR caps and to upgrade to fast recovery diode and bridge rectifier. Is the bridge rectifier BD902 and the diodes to be replaced D901/902? I've also highlighted on the attached.

PSU.GIF

Thanks again.
 
...the blind leading the blind...

If any of those caps in the signal path are 4.7uF or smaller you might consider WIMA film caps..

BD902 is a bridge rectifier. I think your rules regarding the PSU are more relevant to actual power amplifiers and not necessarily a preamp...

Hopefully someone with more experience will chime in.
 
Haha got it. Ok thanks.

What is the reasoning to use film for only 4.7uF or smaller? Just due to size constraints?
 
Any idea how to go about pulling this headphone pcb off? There’s some caps on the underside I was going to replace.

Also, that blue piece to the right of the headphone board looks like it might be leaking. It’s attached to the power switch. Any idea what that is so I can replace?

Thanks again for all the help and no worries if you don’t know.
 

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Blue piece? You mean the ceramic "surge" line power capacitor? leave it alone- doesnt need replacing. I completely restored and upgraded a 1020 last summer. Everything, not just a recap. Sold it for BIG bucks to a real audiophile. Get the service manual. It will tell you what all the lytics, resistors, transistors, etc values are.

Do your research on previous posts on AK.
 
Yeah exactly. Thanks for the advice. I have a service manual so know all the parts I need just wasn’t sure which would be best to get. Did you replace all the electrolytics with films? Did you use 1% metal film for the new resistors? I’ve looked at numerous threads here and elsewhere but it’s more piecemealing info together so just wanted to see if someone had it all up front. Thanks again
 
I finally have gotten around to restoring my NAD 1020. It has been sloppy and slow going but almost have done everything. Praying it will work once done. I'm running into a couple problems though. The preamp is so old the copper tracing has been coming up and the fuse clips have snapped off. Does anyone know what fuse clips I need to replace them? They are pictured in the image below.

Pics so far below. Sloppy and slow going, but almost have done everything.
 

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I've finally finished the recap and put in all new resistors. Unfortunately, the amp is still not working properly. I can hear music playing faintly in the background and there are big static bursts when the bass kicks in. Does anyone know if there are some standard checks I can do to help narrow problems down? I'm trying to avoid going through and checking values each and every resistor.
 
I'm still having trouble with this. Again, I've recapped the whole preamp and put in new resistors. I'm getting 200mv out of both my pre-outs though which is not good. Behind the fuses I'm getting around 25v which I think is normal. I don't know how to read a schematic and diagnose this further though. Any ideas?

I've attached a pic of the schematic as an example. So behind resistor 904 (highlighted) should I be showing -29v on my multimeter? Is that a way I can just go through this and see what is off?
 

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Clip your multimeters black test lead to the metal chassis(ground). With your red test lead . Probe each end of that resistor.
 
avionic said:
Clip your multimeters black test lead to the metal chassis(ground). With your red test lead . Probe each end of that resistor.
Click to expand...

Thanks, that is all very helpful. All my voltages are off (see pic attached). Starting with the fuses which I think should be -20v and +20v, I am reading -25.6 and +25.6. Is that high or is there a tolerance for that? Accordingly, everything else is off throughout the board.
 

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