The adjustment middle part in the pot becomes weak I believe, and will start to move with vibration. I don't know if you can find them, but that would be the thing to replace in my opinion, however I'm not sure if I'm correct in this 100%. The left hokus pokus on my ToM needs re-adjusting about every 3-4 months, so nothing I'm concered with now, but if it became even a weekly thing, I'll review my options.

Do you notice any visible change in the adjustment once it stops working, as is, where you previously set it, it apears it has moved? If so, I might try setting it, and gluing it there. You could always heat that up later to remove, and if it doesn't work, it's not like you're hacking anything that won't be replaced anyway.

C3 should be removed regardless of the condition. Read this:

http://www.pinbits.com/index.php?main_page=product_info&cPath=13_4&products_id=188

hmm, good read.

There must be a component on the board this is shorting out when it heats up, which makes me think it is an IC. My knowledge base ends there. Try checking RGP for anything similar to your issues. Is a resistor slowly going open...?

This "sounds" like it might assist, but you may want to spring for the pinbits replacement at this point. I hate recommending a cop out like that, but I don't know what else to tell you, unless someone else has anything to add.

As for pinbits, they seldom go out of stock for anything. The website states this, but when you call, they usually have them, just haven't updated the site. They are a "mom and pop" shop so to speak, so their system gets updated when they get around to it.