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Restoration NAD 3020 power switch

 
Thebirdman61
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Hi, new on here and looking at my first amp restoration. I'm looking for some help as the NAD 3020 amp I bought on spec at an auction very cheaply does not power on. All that happens on plugging in is a fizzing/crackling sound from the power switch. I have tried to source a replacement (Alps SDU3P TV5 or Sanyo SW171) switch but am having no luck getting one for what I would consider a reasonable price. I don't really want to spend too much on this switch only to find a bundle of other things wrong as well.  I know this is a very basic question, but everyone has to start somewhere. I've fixed up record decks and done some limited work on speakers, but have always stayed clear of amps up until now.Does anyone know of somewhere I might be able to get one or is there anything else I could use instead?

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Topic starter Posted : 01/08/2021 10:31 pm
Nuvistor
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@thebirdman61 
I can’t help with a replacement but is it possible to bypass the faulty switch? That would allow testing of the rest of the amplifier to determine if it’s feasible to repair.

Frank

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Posted : 02/08/2021 7:14 am
Doz
 Doz
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There's a copy switch available on AliExpress... it proports to be genuine, but I wouldn't bet the house on it..

There's also a Sony switch which fits, but that's no easier to source.

They're a wonderful amplifier, and have a few stock issues... Here's one I did here :

https://andydoz.blogspot.com/2020/12/nad-3020-repairs.html

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Posted : 02/08/2021 4:35 pm
Thebirdman61
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I’ve had a quick look at the blog and it will be a great help if I get that far. I had thought about bypassing the switch, but is it a simple case of taking it out and rejoining the wires or is there some form of resistor or likewise in there that needs taking into account. There are some form of components attached to the switch which from what I have read are some form of suppressors and may not be completely necessary, but not sure. The switch is shown below. Anything I need to think about before attempting a bypass?

41868A5C 0F5E 4CDA A934 B1286AEEAD74
8D17AC25 07E4 4B22 91C6 4C0A617DC060

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Topic starter Posted : 02/08/2021 8:05 pm
Nuvistor
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@thebirdman61 
I have never seen a NAD amp so can’t advise, can you draw the circuit out around the switch, that will show what the components are doing. I presume mains filters or switch spark suppression but that’s guessing.

Frank

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Posted : 02/08/2021 10:03 pm
crustytv
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@nuvistor

The NAD 3020 Service manual is in the technical library.

Crusty's Collection: Read the repair blogs
Crustys Youtube Channel: If you want to follow me on Youtube, please consider subscribing
Vrat FaceBook: Follow us

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Posted : 02/08/2021 10:30 pm
Nuvistor liked
Nuvistor
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@crustytv

Thanks Chris, its been a long day. Circuit of the mains input attached, all I can see are two capacitors for spark suppression. If the switch is beyond repair I would snip the lugs off leaving the caps and wires attached and floating and short the sections out. That way the switch is completely out of circuit.
If you think you can repair the switch them unsolder the components and wires before bypassing.

A5836D61 2148 4688 B0FB BE7481688244

Frank

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Posted : 02/08/2021 10:43 pm
Thebirdman61
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thanks for the help everyone, much appreciated. I thought they were spark suppressors but wasn’t sure. I’ll unsolder and have a go at mending the switch if I can. Nothing to lose. In the meantime I’ll try bypassing the switch to see what else may be required. Thanks also for the pointers to the repair blogs, videos etc. That gives me a great start. I’ll report back on progress and probably ask for a little assistance if that’s ok.

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Topic starter Posted : 02/08/2021 11:11 pm
Thebirdman61
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@doz do you have the link for the switch on aliexpress, as I can’t seem to locate it, and also the model number for the Sony switch if you have it?

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Topic starter Posted : 02/08/2021 11:15 pm
Doz
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@thebirdman61

I've spent a little time searching AliExpress to little avail this morning. There's a switch which looks like it may fit, but is only single pole. 🙁

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Posted : 03/08/2021 10:02 am
Thebirdman61
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@doz Thanks. I'm away at the moment so when I get back in a few days, I'll make a start on the amp and go from there

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Topic starter Posted : 04/08/2021 9:18 am