Recent content by DougD

Located the transistors to remove - thanks for that and will advise. I think 10/32/79 was a leap year on the PL calendar.

Assume you're referring to the volume pot? If so is it worth attempting to loosen for access to clean vs replace? Thanks. Assume you're referring to the mute switch that attenuates the volume? I looked at the schematic to see if I understood how to defeat this function. Way above my pay...

For anyone still listening - I cleaned and lubed the tone pots since they were off the board, and did the same to the balance pot in situ. I spent a couple of hours inspecting the board with a magnifying glass for gaps or cracks in solder joints and traces. Remelted a few joints that were a...

Thanks - I'll do that. Not sure what they're called but what look like solder tracks on the PCB - is it possible for a crack to develop there?

Thanks for that - makes sense. Does that suggest it's something immediately adjacent to the pot or could it be anywhere? I'll reflow everything I didn't touch the first time around. In the meantime I've already got the tone pots off the board so might as well clean them. Didn't realize how...

After running without incident for a week at low volume the left channel was dead when I turned the unit on this morning. As I recall the right channel was dead when I first energized the unit after reflowing the solder joints. I left the volume control at a low level and began exercising...

Thanks for that - I see the hole at the bottom of those pots next to the board. I reflowed the solder joints as suggested, and when I turned the system on the right channel was dead - popped back at high volume. Strangely, no drop out all afternoon at low volume, and that's unusual...

Thanks for the warning. The volume control is stepped or detented so I imagine there are springs of some sort internally and that things are intricate inside. I'll leave that piece to the end and hopefully we resolve the problem before we come to that.

Thanks for clarifying the cleaners and lubes. The following pics are the bass and treble pots - don't see any type of opening that would allow entry. This is the balance pot, where I do see holes at 3 and 9 o'clock along with slits around the circumference.And finally the volume pot with no...

What a treat finding such a knowledge base willing to share - it's much appreciated. Hoping some additional detail will help pin down the source of the problem. The fact that two services have eliminated the problem - only to have it return - suggests something's being cleaned (inadequately)...

Electronics Service Labs in Weathersfield CT replaced that same switch on my 3300 Series 2 a few years ago. You might give them a call.

I have a 45 year old system that I've managed to continue to enjoy with one exception. The preamp continues to drop a channel at lower volumes - in all modes - can usually bring it back by increasing the volume dramatically. I've had both the power amp (300 Series 2)) and preamp serviced...