minimizing volume ends with a rude surprise...

I have two boomboxes that have the same curious problem.When I move their volume sliders down to their minimum positions,the sound all of a sudden will BLAST from their speakers .Overlaying the loud music is a static much like a needle being dragged diagonally across a record.This only happens when I move them to the very bottom of their throw.Usually I hit the power switch very quickly to shut things down.While these boomers are off,I work with the sliders a bit before turning them back on.This seems to correct the problem.I now know to stop at "1" instead of "0" when turning down the volume on these units.

Now I've heard of scratchiness in volume controls but never the kind of rude "explosive" occurrence I'm getting from these two boxes.Has anyone else experienced this on boxes with a volume slider?How do I correct this problem?

Let me guess... is one of them a Sanyo M9935?

Your somewhat close Fatdog.One is a sanyo C4 and the other is a Panasonic RX-C20.Given the fact I have 2 boxes that do this,it couldn't be all that uncommon a problem.Anyone?

I know my original Sanyo M9935 I had back in the day developed the same problem. Strangely enough, the Sanyo M9935 I found at Goodwill about five years ago was the exact same way. It could be that the parts supplier had a huge run of bad pots.

Oh, and DeOxit doesn't help the problem at all. Is that also correct?

I've never actually used DeOxit as I have had a reasonably competent tech guy until recently.Is there a downside to spraying it through the sliders hole in the front of the C4? These slots aren't exposed on the front of the Pana so I can't really use that approach on that box.I'm hoping I won't have to open either box to access the sliders from the inside of the boxes.

Problem is in the sliders, that is for sure. Hopefully, they are just dirty but there is also a possibility that they are worn. If worn, you can sometimes disassemble them and any carbon that was worn off could be redeposited using brush-on carbon restoration product. If dirty, I never recommend spraying directly into the sliders from the outside. #1, any dirt/dust that typically builds up in that area will get pushed into the sliders causing all sorts of problems. #2, putting sufficient solvent through that slot to be effective usually means that the excess will run off on the inside, sometimes to some undesirable areas. If it runs off and gets on the tape belts, it could ruin them. Also, the solvent fumes has a tendency to remain in the case and bake/fumigate the interior parts. That's because the sealed case doesn't evaporate the solvent as quickly as it could/should. Again, this could cause deterioration of the rubber parts and also may result in a cloudy film to develop on the radio dial. Also, if the solvent should run off and work it's way into the tuner capacitor vanes, it will throw off the capacitance of the tuner. At best, temporarily. At worst, permanently. The reason is that any film that remains on the tuning capacitor vanes after the solvent evaporates will cause a permanent change in capacitance. Even if the solvent was a true no-residue solvent, the sliders themselves would originally have been manufactured with grease/lubricant inside and the resulting wash-off from the solvent WOULD leave a film.

Superduper lives up to the name,that's for sure .Thanks for the detailed reply.This also answered a question about the dangers of trying to fix the problem with rotary pots from the outside. I had heard this was a bad idea some time ago but forgot the reason opening the case was the safest method.

This at least gives me a fix on how to approach the issue.Now I've got to get the nerve to open both boomers.I've done this before but sometimes you can run into problems if they're not basically hollow black boxes on the inside.Anyway,thanks Superduper and Fatdog for your responses.

Just get some service spray jovie take the knobs off and spray the switches working them in left right about 50 times, i have never had any issues doing it this way, make sure your box is off and leave dry for about 30 mins just to be safe.(done over 50 boxes this way) including lot's of m90's.

Superduper hit the nail on the head. My RX-C300 and PC-55 did the same thing. If you can play with the slider or rheostat (pot) by wiggling it and it stops, most likely the trace is worn.

yes thats the case with those like that i fixed a hitachi 3d with the same problem bad trace in slider