Burning Fingers
Tele-Meister
Hi Guys...I'm working on an Ampeg SVT HD 300 watt monster and found that Channel 1 only worked with the ultra high switch engaged with a very thin sound and then a loud bass thump happened at half volume. With the switch not engaged there was no volume until the volume was turned up halfway then the loud thump. Obviously a bad pot...but curiosity got the better of me so I pulled the pot apart and found this...The carbon track had disappeared from a lot of the pot !.
I asked the owner if he had done anything to the amp recently and he said he pulled the amp apart and squirted cleaner into the volume pot as it was scratchy...what sort of cleaner...Lighter Fluid!..Considering how long it takes to get these amps apart to be able get to the pots ( it took me 20 minutes to disassemble and another 20 minutes to reassemble ) I am amazed that he could be bothered going for a 10 minute drive to get electrical contact cleaner and lube. Luckily he didn't "clean" the other pots as well.
This what the carbon track looks like..
I asked the owner if he had done anything to the amp recently and he said he pulled the amp apart and squirted cleaner into the volume pot as it was scratchy...what sort of cleaner...Lighter Fluid!..Considering how long it takes to get these amps apart to be able get to the pots ( it took me 20 minutes to disassemble and another 20 minutes to reassemble ) I am amazed that he could be bothered going for a 10 minute drive to get electrical contact cleaner and lube. Luckily he didn't "clean" the other pots as well.
This what the carbon track looks like..