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Figured I'd post this as it might help somebody else out...I had this Hot Rod Deluxe 3 which after about 4 or 5 hours would cut out...according to the customer.....So I took the back off and looked for any signs of overheating...couldn't find any...found some bad connections....left the amp turned on and every so often would pick up a guitar an play for about half hour and then turn the guitar volume down and just let the amp run...I could not get this bloody thing to fail.....I tapped tubes to see if they were erratic...checked cables and connectors, jacks, etc....every day when I started my repairs I would turn this amp on and let it run the entire day and into the night....Called the customer and he re-affirmed his problem....So after another week of testing I decided to put the back on and just let it sit there...after a few hours, it cut out...a heat build-up maybe?? I then noticed that the drive channel was still working.....and if I turned up the clean volume all the way you would get a very low level from the speaker...So.....now that I had the problem I decided to hit some components with some cold spray....I hit the filter cap for the first stage and the sound came back...I heated it up with a heat gun and it went again...so I replaced the filter cap....convinced I had the problem solved I put the back back on and ran it again...Still cut out....WTF?? So upon closer inspection, there was a relay very close to this filter cap and when I touched it with the smallest amount of pressure, the sound came back. Hauled the board out again and check for broken trace or solder connection. No problems there. Took out the relay and hooked it up to an external power supply and connected a DVm to the relay contacts....found that one side would not switch properly and if I pressed on the top of the relay housing, the relay would switch....Replaced it and it worked fine after....Ran the amp for another two days with no problems....So there you have it...I had the back off the amp and could not get the problem to re-occurr....that is one mistake I will not be making anymore....and I hope this helps somebody else out in the future...
Cheers,
Bernie
Cheers,
Bernie