Switch noise

peace brainerd · 14th January 2006, 12:30 AM

What commonly causes panel-switch noise? I just brought home a NAD 7020 receiver that looks like it just came out of the box. I fell in love with the sound. I then opened it up and gave the switches a thorough going over with electronics cleaner and a mini-vac. Very gently cleaned everything else of dust and put'er back together. Volume and balance scratchiness were eliminated.

During a very careful audition I noticed a faint ragged cutting out in the left channel and my heart sunk. I was just starting to think I'd be problem free.
As I eliminated possibilities, I noticed that moving the Selection rotary switch very slightly produced the cutting out. If I held it between stops (between aux and phono) it played solid and clean. The phono detent does something similar. FM Mute, FM, and AM are fine.

Now, I understand pretty well how mechanical volume and balance controls can get noisy due to their construction. But a selector switch should either work - or not. Right? Should I attempt to take it apart?
This would be a huge pain in the *** because the switch is small and connected to the board.

Any magic bullet cleaners you can recommend?

poobah · 14th January 2006, 12:50 AM

Hey Dude,

Consider this, cleaners don't really clean anything... they just move the gunk somewhere else really... you may have had a droplet settle on that switch postion. sme cleaners actually carry things away but they are all illegal now I think. Try spraying that thing again but this time while you're moving the switch back and forth until it dries.

Just a thought,

dnsey · 14th January 2006, 01:30 AM

In the days of dual-standard TV sets, the standards switch (which worked in much the same way) was probably the most unreliable component in most sets. A good clean with solvent and - the important bit - vigourous operation, almost always solved the problem.
The trouble is that the contacts are designed to be self-wiping, but if the switch is rarely operated, they can't do much in the way of self-maintenance.

peace brainerd · 14th January 2006, 05:19 AM

dnsey, you may be on to something there. I've often wondered why it's the speaker selection switch that people often gripe about "going out" first. For most users, it has to be the one that sees the least use.

I guess I'll have to really blast it with cleaner and try to get the vac nozzle near to it.

Anybody have suggestions for a killer solvent to use here judiciously?

poobah · 14th January 2006, 02:18 PM

"TV TUNER CLEANER" or "ELECTRONICS" should do the trick for you... you can something at shidio rake... oops, Radio Shack I bet.

peace brainerd · 14th January 2006, 08:37 PM

television tuner cleaner is pretty much what was used . I'm looking at a can of WD-40 right now and getting tempted. Why not? Go ahead, scream away. Gnash your teeth. It's always done wonders on my car and motorcycle electronics.

Cal Weldon · 14th January 2006, 11:18 PM

No flame throwing here. It's all I ever use for switches and pots. Rotary or slider, works like a charm.

Thanks for allowing me to come out of the closet.

My name is Cal and I use WD40.

Warning: This cleaning is done by professionals on a closed course. Do not attempt this at home. Actually I have no idea how bad it is but I have many, years old gear that hasn't suffered. In fact you seem to only need it about every ten years.

anatech · 15th January 2006, 03:15 AM

Hi Cal,
WD-40 can be an excellent switch cleaner. But, all power carrying contacts should be totally clean, no residue. That goes for speaker relay contacts too. The "cleaner" will burn in an arc and make things worse.

Then there is "that smell". In controls you do not want to wash out the lubricant. Clean the metal wiper only. The carbon track is not the cause of the noise.

I use both De-Ox-Id and DeOxid. Both work well. Use as little as you can.

-Chris

Poobah,
Tuner cleaner? Sigh.

poobah · 15th January 2006, 03:27 AM

OK call me pooby...

The good stuff has acids... I can't tell some one to wash his boards in the sink!!!

testlab · 15th January 2006, 05:31 PM

Deoxit 5% is the stuff to use. WD-40 will damage anything with phenolic(pots), boards and some plastics. It is really good at soaking in to carbon composition resistors and changing their value.

Ultimately, when it comes to switches, you should just replace it.

14th January 2006, 12:30 AM	#1
peace brainerd diyAudio Member Join Date: Nov 2004	Switch noise What commonly causes panel-switch noise? I just brought home a NAD 7020 receiver that looks like it just came out of the box. I fell in love with the sound. I then opened it up and gave the switches a thorough going over with electronics cleaner and a mini-vac. Very gently cleaned everything else of dust and put'er back together. Volume and balance scratchiness were eliminated. During a very careful audition I noticed a faint ragged cutting out in the left channel and my heart sunk. I was just starting to think I'd be problem free. As I eliminated possibilities, I noticed that moving the Selection rotary switch very slightly produced the cutting out. If I held it between stops (between aux and phono) it played solid and clean. The phono detent does something similar. FM Mute, FM, and AM are fine. Now, I understand pretty well how mechanical volume and balance controls can get noisy due to their construction. But a selector switch should either work - or not. Right? Should I attempt to take it apart? This would be a huge pain in the *** because the switch is small and connected to the board. Any magic bullet cleaners you can recommend?

14th January 2006, 11:18 PM	#7
Cal Weldon Speakerholic diyAudio Moderator Join Date: Jan 2004 Location: British Columbia	No flame throwing here. It's all I ever use for switches and pots. Rotary or slider, works like a charm. Thanks for allowing me to come out of the closet. My name is Cal and I use WD40. Warning: This cleaning is done by professionals on a closed course. Do not attempt this at home. Actually I have no idea how bad it is but I have many, years old gear that hasn't suffered. In fact you seem to only need it about every ten years. __________________ Next stop: Margaritaville Some of Cal's stuff \| Cal Weldon Consulting

15th January 2006, 05:31 PM	#10
testlab diyAudio Member Join Date: Dec 2005 Location: Grand Rapids MI	Deoxit 5% is the stuff to use. WD-40 will damage anything with phenolic(pots), boards and some plastics. It is really good at soaking in to carbon composition resistors and changing their value. Ultimately, when it comes to switches, you should just replace it. __________________ It's not whether you win or lose, it's how you lay the blame.

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14th January 2006, 12:50 AM	#2
poobah diyAudio Member Join Date: Nov 2005	Hey Dude, Consider this, cleaners don't really clean anything... they just move the gunk somewhere else really... you may have had a droplet settle on that switch postion. sme cleaners actually carry things away but they are all illegal now I think. Try spraying that thing again but this time while you're moving the switch back and forth until it dries. Just a thought,

14th January 2006, 01:30 AM	#3
dnsey diyAudio Member Join Date: Mar 2004 Location: Shropshire, England	In the days of dual-standard TV sets, the standards switch (which worked in much the same way) was probably the most unreliable component in most sets. A good clean with solvent and - the important bit - vigourous operation, almost always solved the problem. The trouble is that the contacts are designed to be self-wiping, but if the switch is rarely operated, they can't do much in the way of self-maintenance.

14th January 2006, 05:19 AM	#4
peace brainerd diyAudio Member Join Date: Nov 2004	dnsey, you may be on to something there. I've often wondered why it's the speaker selection switch that people often gripe about "going out" first. For most users, it has to be the one that sees the least use. I guess I'll have to really blast it with cleaner and try to get the vac nozzle near to it. Anybody have suggestions for a killer solvent to use here judiciously?

14th January 2006, 02:18 PM	#5
poobah diyAudio Member Join Date: Nov 2005	"TV TUNER CLEANER" or "ELECTRONICS" should do the trick for you... you can something at shidio rake... oops, Radio Shack I bet.

14th January 2006, 08:37 PM	#6
peace brainerd diyAudio Member Join Date: Nov 2004	television tuner cleaner is pretty much what was used . I'm looking at a can of WD-40 right now and getting tempted. Why not? Go ahead, scream away. Gnash your teeth. It's always done wonders on my car and motorcycle electronics.

15th January 2006, 03:15 AM	#8
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi Cal, WD-40 can be an excellent switch cleaner. But, all power carrying contacts should be totally clean, no residue. That goes for speaker relay contacts too. The "cleaner" will burn in an arc and make things worse. Then there is "that smell". In controls you do not want to wash out the lubricant. Clean the metal wiper only. The carbon track is not the cause of the noise. I use both De-Ox-Id and DeOxid. Both work well. Use as little as you can. -Chris Poobah, Tuner cleaner? Sigh.

15th January 2006, 03:27 AM	#9
poobah diyAudio Member Join Date: Nov 2005	OK call me pooby... The good stuff has acids... I can't tell some one to wash his boards in the sink!!!

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