Pioneer SA 6500 into a Numark Tt-200....left speaker going off randomly! Help!

[soma89]

Hello everyone..

I have a Numark tt200 with a Stanton 500-II into a Pioneer SA-6500 amp.

I've noticed that the Left speaker will sometimes get lower in volume, fuzz out, and/or go completely off. It does come back on most of the time though but this is really annoying. IT ALSO HAPPENS WITH HEADPHONES. One headphone will always go off.

What I have tried (but failed):

- I took off all the knobs on the amp and sprayed them with contact cleaner
- I sprayed contact cleaner all over the back aswell into the inputs of the amp. ( i have yet to open up the amp tho)
- I sprayed contact cleaner in the cartridge input.
- I got new speaker wire
- I switched the speaker wires to go into the "B" section and now i use B as my main channel.

NONE OF THESE THINGS WORKED.

Does anybody know what could be the problem here? Any help is greatly appreciated. I'd prefer to try to fix the problem myself.

Thanks a lot!

[Pentode]

Think your going about it all wrong from your description, is it the power amplifiers or the pre-amp that's at fault?

One quick test is the finger test, no, no not on the power transformer .... try touching the top end of the volume control, if you can't reach it then get a screwdriver to do the job making sure you keep a finger on the metal part....

... and careful not to short anything out!!!

What you should hear if the PA stage is OK is a kinda buzz, local hum pick up from the mains - if it produces such noise this would tell us the power amps are probably OK and the fault lies further up stream before the volume control.... reason I suggest this I've known electrolytic capacitors (caps) dry up or go leaky.

We can go further hunting for clues.... get a crystal earpeice ground one end and dab the other on the volume control.... if the pre-amps ok then you'll hear what ever signal is being fed to the input.ie Radio CD or tape.

These two test tells us a lot and would point you in the right direction.... this is the first step I feel.

Another suspect I've had many times is the output capacitor on 'single ended' power amplifiers.... those that do not use a split rail.

You can appreciate it's all too easy to say 'change this n' that' and it'll be OK, it may well be something simple like a 'dry joint' a soldered connection gone bad, but we need to know which way to go up stream or down stream from the volume control.

Dave

[CBRworm]

I would try another source device and see if the problem persists.

If it does, does pushing buttons or changing volume/balance have any effect?

If so I would try using DEOXIT and/or faderlube instead of contact cleaner.

Another suspect would be the protection relay (if it has one).

[gmphadte]

How old is that thing?