Mojotone CTS pots?

[Randall]

JM, the idea of having to rip that board out and re-doing it actually make me weak.

And I should add that I got it down to 3-5 mV across the volume pots, not volts.

[Enzo]

I have had good results running a heat gun down the board to spot bake the contaminants off the boards.

[Randall]

Enzo, can you further explain this? Before building, as a repair, with components in or out?

[Enzo]

I am talking about in repair, but I suppose any time I get conductive eyelet board, I would think to use the method.

Imagine your windshield is covered in ice, or you have a frozen water pipe. You get out a hair dryer and start at one corner of the windshield and start to melt the ice. YOu watch as the thaw line moves along and you follow with the hot air stream, chasing the edge of the ice as it retreats. When I thaw a pipe, I start at one end (I admit I am more likely to use a propane torch), heat the pipe until I see the frosty look change over to plain old pipe. Then again, I follow the thaw line down the pipe until I hear the water start to flow.

When I find a conductive eyelet board, at least on old Fenders, it is generally some sort of surface accumulation of contamination that has adsorbed moisture. So I start in the area most affected, and hit it with the hot air stream. I can see the dull waxy appearance of the board change to a clean dry look as the waxy stuff evaporates away. Then I follow the edge of that - the thaw line if you will - away to create clean areas as needed. It usually works, at least for me.

If yours is absorbed into the board rather than on the surface, I can't say how mu8ch more or less effective it might be.

[Randall]

I see. My situation is with a new Mojotone board in a new build, so I think we are not talking about the same conditions. Not waxy at all.

[Enzo]

OK, fair enough, but th technique might still work if the board is absorbing.

Pick a spot that seems conductive and try it there. yes, I do it on populated boards.

[Enzo]

I may be full of beans, just thinking out loud so to speak, but if I had a bare board, and I had reason to believe it might be prone to picking up moisture, perhaps a wipe of very light oil on the surfaces might help?

[Randall]

But would it keep it from future absorbing? In which case I would trust it.

[Enzo]

Hard to say.

[Mick Bailey]

I've baked the material in sheet form experimentally to get the moisture out of it. It takes a fair bit if heat for a long time to get rid of the trapped moisture from the centre. But, the resistance began to creep down after a few weeks over the winter. The only thing I've found is some aerosol silicone oil which will soak in and insulate the board, but you've got to get it dry enough in the first place else you'll be trapping the moisture. The silicone I found has a solvent carrier and is very searching. I'd rather not have the problem to begin with so I only use black epoxy-glass now. Avoid using ordinary mineral oil, though transformer oil could be used at a push. Silicone would be better.