Go Back   Home > Forums > >

Solid State Talk all about solid state amplification.

Nad 3020A developed problems
Nad 3020A developed problems
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools
Old 13th June 2021, 05:32 PM   #81
Peterbt is offline Peterbt  France
diyAudio Member
 
Join Date: Jun 2021
Okay. I won't then. If that switch is defective I don't know if it's possible to get hold of a replacement one. Should I resolder the white wire to the switch as it was or just let it be right now?
  Reply With Quote
Old 13th June 2021, 05:32 PM   #82
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
Nad 3020A developed problems
Your not missing anything I spotted that as well but I'm just looking at the fact it works with it disconnected and that the control comes up to the expected 13 volt or so.

So the switch has to be conductive.

Erm... I know some of the resistance checks have been a bit open to interpretation shall we say and so I'll put the readings down to that. Sometimes it can be difficult to get a probe to connect through flux and grime... it all comes with experience.

Peter... just swap the wires over from one side to the other and see if it works.

I was actually going to say Deoxit might be worth a try to free things up but again experience comes into play and you don't really want to be filling the mains part of the switch with anything that could cause arcing. You would have to direct it into the top part of the switch where that little spring is (not the coil spring, the other little actuator thingy in that groove... assuming it looks exactly like the picture.

Feeding time
  Reply With Quote
Old 13th June 2021, 05:34 PM   #83
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
Nad 3020A developed problems
Quote:
Originally Posted by Peterbt View Post
Okay. I won't then. If that switch is defective I don't know if it's possible to get hold of a replacement one. Should I resolder the white wire to the switch as it was or just let it be right now?
Swap them over, see if it works.

If it doesn't then leave the wire disconnected for now. Make 100% sure it can not touch any live parts accidently.

If you can't get a switch then get a 4.7meg (4.7 million ohm) resistor and solder it across C531 and leave the switch disconnected.

Definitely feeding time now
  Reply With Quote
Old 13th June 2021, 05:39 PM   #84
Goldie99 is offline Goldie99  United Kingdom
diyAudio Member
 
Join Date: May 2013
Location: UK
Peter - in the last photo I posted, with the 2 yellow lines & 2 orange lines, you can relocate the wires to the 2 orange terminals, again the order doesn't matter - they're just a second set of terminals which are identical to the first set, but have never been used, so may be cleaner.

If the top (outside) of the switch is dirty, it would be worth taking a pipe cleaner and cleaning it with something like IPA, it's just possible there might be something conductive on the outside of the switch.
  Reply With Quote
Old 13th June 2021, 05:39 PM   #85
Peterbt is offline Peterbt  France
diyAudio Member
 
Join Date: Jun 2021
Okay, thanks. I will and I pass on the Deoxit if it's that touchy. Yes feeding time.
  Reply With Quote
Old 13th June 2021, 08:34 PM   #86
Peterbt is offline Peterbt  France
diyAudio Member
 
Join Date: Jun 2021
I've swapped those wires but no change.Still no sound. I'll disconnect the white wire again. Could you give me the color code for that 4.6 meg resistor? I don't think I have any but it may be easier to look for one. Thanks
  Reply With Quote
Old 13th June 2021, 11:15 PM   #87
indianajo is offline indianajo  United States
diyAudio Member
 
indianajo's Avatar
 
Join Date: Jan 2010
Location: Jeffersonville, Indiana USA
Yellow violet green. Unlikely to be stocked. I never owned any.
__________________
Dynakit ST70, ST120 (modified), PAS2,Hammond H182(2 ea),H112,A100,10-82TC,Peavey CS800s, M-2600, MMA-875T, SP2 (2004) speaker, PV8 mixer, Herald RA88a mixer (modified), Steinway console, Wurlitzer 4500, 4300
  Reply With Quote
Old 14th June 2021, 12:27 AM   #88
TonyTecson is offline TonyTecson  Philippines
diyAudio Moderator Emeritus
 
TonyTecson's Avatar
 
Join Date: May 2003
Location: Maybunga, Pasig City
for such an aging amp, a recapping is timely..
  Reply With Quote
Old 14th June 2021, 06:05 AM   #89
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
Nad 3020A developed problems
Quote:
Originally Posted by Peterbt View Post
I've swapped those wires but no change.Still no sound. I'll disconnect the white wire again. Could you give me the color code for that 4.6 meg resistor? I don't think I have any but it may be easier to look for one. Thanks
Firstly Peter... how do you feel the amp behaves with the wire left disconnected? I was just thinking a bit more on this.

Are there any problems with excess noises (bangs, thumps etc) as you turn the amp on and off with the mains switch and I'm actually thinking more of noises at switch off now.

The resistor I suggested would not actually help much with noise at switch off. When you turn the amp off the switch connects the mute circuit to the negative supply and it relies on that negative supply lasting long enough (as the caps discharge) to hold the amp in mute while the main amplifier power supply caps also discharge and the whole amp then stops functioning.

I have some other ideas on the switch itself. You say it is very dirty. How confident are you of putting some paper towel under and around that first part of the switch, then hold the amp vertically on its front and give that switch area a good clean with your spray. Work the switch on/off many many times and use the paper to absorb the gunge. Flood that part of the switch with cleaner but keep the amp vertical to stop it running into the mains area of the switch.

(By disconnecting the switch and also you confirming the voltage is correct on D507 we have proved beyond doubt that leakage is the problem)
  Reply With Quote
Old 14th June 2021, 06:08 AM   #90
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
Nad 3020A developed problems
Quote:
Originally Posted by TonyTecson View Post
for such an aging amp, a recapping is timely..
It could very well be Tony but always best to fix the original fault first I think.
  Reply With Quote

Reply


Nad 3020A developed problemsHide this!Advertise here!
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
NAD 3020A schematics or parts list ZuMbAiU Solid State 27 21st October 2014 08:52 AM
NAD 3020A Schematic JDeV Solid State 9 10th November 2007 05:14 AM
need help for NAD 3020a vubkevin Solid State 23 26th September 2007 07:18 PM
NAD 3020A -info and reapir thread> ZuMbAiU Solid State 24 28th February 2006 04:18 PM


New To Site? Need Help?

All times are GMT. The time now is 12:09 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2021 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2021 DragonByte Technologies Ltd.
Copyright ©1999-2021 diyAudio
Wiki