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Old 5th October 2006, 03:48 PM   #1
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Default NAD 3020 Channel Problem

Hey all,

My NAD 3020 came with a short and a blown transformer; I paid a shop to fix it, and it's worked fine since, although I've always had trouble with switching channels. I finally cleaned the contact plate and it seemed a LOT better, but now one channel or the other sometimes fades out a little...this is usually fixed by turning the power on and off quickly. I'm wondering if I need to do a better job on the switch plate, or if the original gremlin is back...

thanks!
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Old 5th October 2006, 03:52 PM   #2
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Is this a pre/main swicth?, ...or a Soft clipping switch?? De-ox-it and working the switch should work if it's only oxidation.
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Old 5th October 2006, 04:09 PM   #3
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It's a main switch. The channel fades while playing and seems to only happen on the phono stage. Deoxit where, on the switch contact plate again?

thx
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Old 5th October 2006, 04:22 PM   #4
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If it's the pre/main coupling switch, it's most likely to affect all sources. Depending on the switch contact alloy used, the switch contacts can re-oxidize. If you use something like De-ox-it, it will leave a film on the metal and prevent oxidation for a long time.
Confirm where the problem is coming from (Check tape monitor switch too) ...spray the control, and work the switch. By working the switch, you will scrape an oxide layer off. If you can nail where the problem is, and De-ox-it doesn't fix it, you probably have to replace the part. .....Sometimes push switches have a U-shaped switch leaf, where the spine gets fatigued and loses contact pressure. You can rebuild these switches if you have junkers laying around with switches made by the same OEM. NAD??? I think they might use Apls switches. Gray body, brown phenolic top??? That would be for the Tape monitor style. The pre/main switch I think is a slide switch on the back panel.

I think some of those older NAD's had some sort of a circuit breaker in their output sections? I can't remember, it's been awhile. If they did indeed use breakers, I can't remember them being problematic. I can't say the same for the Soft clipping stuff.
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Old 6th October 2006, 12:19 AM   #5
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It does seem to be happening on all channels after all...I will try some deoxit spray, I was using a contact cleaner pen. Thanks!
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Old 6th October 2006, 12:33 AM   #6
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Quote:
I will try some deoxit spray, I was using a contact cleaner pen.
Yeah, you want to use the spray and spray into the control. Try to see where the switch contacts are visible, or locate a hole into the switch. Use the extension nozzle and spray directly in the switch. Just a quick burst. Then work the switch. The DeOxIt needs to get directly onto the contact area. I apologize if you already know this. The deoxit is expensive. No need to waste it. A little goes a long way.
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Old 6th October 2006, 02:05 AM   #7
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Not at all, it's good advice. I usually have to figure out the techniques by trial and error
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Old 6th October 2006, 03:10 AM   #8
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Hi there,
I've rebuilt a couple of these things, so I'll take a stab at helping:

There isn't a pre/main coupling switch, it uses jumpers. If the jumpers are the original nickle-plated wire 'U's that come with the 3020, throw them away, and use a short, normal, interconnect. I build my own jumpers for this purpose, with good RCA plugs, and a short bit of REALLY good wire. There's no need to connect the grounds, just one wire from one center pin to the other is good.

Now, speaking of RCA's, the RCA jacks on the back of the 3020 were barely passable when new, and after all these years they probably fall into the "suck" category. The center conductor of those jacks is especially horrible, it doesn't wrap completely around the pin of the plug connected into it (trying to avoid risqué word-imagery here, lol). The center conductor of the jack is only a strip of metal at 9 o'clock in the opening if you are looking down at the amp, from behind. It is entirely possible for the body of the RCA jack to be so badly worn, that the center conductors don't make contact at all, or poorly, or intermittently. If any of your RCA plugs are "leaning" to the left a little when you look at the amp from the back, they are probably not making good contact. Replacing the RCA jacks with anything else is a serious PITA, so a work around is; clean them thoroughly, I use a good pipe cleaner soaked in Rid-Ox and scrub out the inside of each jack, make sure they are straight up and down from the chassis, and use interconnects that have really good plugs. When connecting everything up, if you look carefully at the base of the RCA jacks, you can see the center conductor as a little metal strip going into the board. Make sure the tip of the plug is against it.

Next, the selector switches can wear out over time (somehow, none of mine have tho). The temporary solution is to drill a SMALL hole in the back of each switch, and make sure the switch is in the outward position when you drill the hole (hint: you can't drill them all at once). Squirt a bit of Rid-Ox in the switch, and work it back and forth.

As has already been mentioned, also clean the volume, balance, and tone controls. It's pretty easy to get cleaner in there usually. As long as you have your screwdriver out, flip the thing over, take the bottom plate off, and make sure there are no obvious broken solder joints, especially under the switches and controls. If you find any, resolder them, preferably removing the old solder and using new.

One other thing, if it has its original power switch, consider having it changed. Power switches can do all sorts of crazy stuff you wouldn't imagine when they start going bad.

If all the above fails, it may be time to start replacing parts. This isn't all bad news, with the right "upgrades", the 3020 can be made to play RINGS AROUND the most current version I've heard, the C320BEE.

Just curious, what work was done at the shop you took it to?

Don Taylor
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Old 6th October 2006, 10:20 AM   #9
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I think he just replaced the transformer after fixing whatever short burned the old one.

This is great info. I actually am running my sub from the pre-out/in jacks. The selector switches on mine have always been "loose", and if I tap one without pushing it in, sometimes the sound comes and goes. Obviously they are not making good contact, but based on how this newer problem happens when I'm not touching it, and seems to happen somewhat gradually, and is fixed only by pressing the power switch, I thought it might be power-related...
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Old 19th December 2006, 10:53 AM   #10
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Just an update if anyone is listening to this old thread -- I bought the $15 DeOxit/DeOxit Gold 2-pack from radio shack, opened up the amp, sprayed in one and then the other, working the switches a lot each time. I also cleaned the RCA jacks. Not only have all my problems been fixed, the buttons no longer feel "loose" when I press them, they actually physically feel more solid and only need one press, and stay seated.
Thanks a bundle all!
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