Noise when adjusting volume

[motoboy]

Hello!

I have an Onkyo TX-8522 with a PSW-10 and two R50's wired "The Polk Way" and since new there is a noise coming from only the left tower when I adjust the volume (either with the remote or manually). It sounds like someone blowing on a microphone with a little popping too. I've checked all the connections and have found no problems. Any idea what this might be?

It's only an annoyance, but a major one when I'm cranking up the Shostakovich in the middle of things.

Thanks for any help.

Mark

[AudioGenics]

bad volume potentiometer... my guess ....

possible to spray clean and lubricate if it is not hermetically sealed
otherwise need to replace

[blakeh]

Hi Mark & welcome to the Polk forum!

It sounds like you may have a bad (or more likely dirty) pot (volume control). Many times these can be taken apart and cleaned with something like DeoxIT (available at Radio Shack).

[dkg999]

I would guess it's in the volume control pot in the Onkyo. Have you tried switching everything channel to channel to eliminate everything else as a cause?

[motoboy]

Yes, I have tried switching speakers, etc. No change. Sounds like I need to do a little surgery. Should I unplug and leave idle for a day or so to avoid shocks?

I have brake cleaner. Is that too harsh for this? I may also have some contact cleaner, which was made for this, right? I do have dielectric grease. Can that be used on a pot?

Thanks for the quick replies!

[Knucklehead]

+1 on the De-oxit, stuff works great.

[motoboy]

Saw this in another thread. Answers my silly questions.



I would recommend nothing other than DeOxit 5% flushing spray. Available from PartsExpress.

http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=341-200

That size bottle will last you for years. I use it to clean/preserve all my switches, volume pots, balance/treble/bass, input selectors, RCA terminals, speaker terminals, etc. Some people like to do an additional treatment with the ProGold (now called Deoxit Gold) to preserve the contact. I usually only do this for RCA and Speaker terminals, but this is definitely an optional step. The basic Deoxit treatment will last for quite a while by itself.

In case you don't know, the general procedure for treating volume/balance/control pots is to open things up to where you can get in behind the pot. Usually there is 1 or 2 holes on the back. Use the extension tube to get the deoxit directly inside the pot. Spray a good amount of the fluid inside. 2-3 second shot. You should see excess coming out. Don't worry about cleaning up overspray unless it gets on a finished surface. The actual spray is non-conductive so it won't short things out. After spraying, move the control knob back and forth through its ENTIRE range repeatedly for about a minute (40-50 times back and forth). That should do the trick. I like to let things dry out for about an hour before buttoning things up.

If you have a multi-meter, service manual, and the knowledge how, this is also a good time to check for DC offset and bias current on the amp. If you don't know what I'm talking about, there is an excellent thread over at AudioKarma in the Vintage Electronics section.

[thuffman03]

+1 on the De-oxit, stuff works great.

+1. This should take care of that.

[motoboy]

Duhhh. I just pulled the knob off the front of the receiver. Cleaned and lubed it up with the Radio Shack brand cleaner. Works perfectly. Thanks for your input!