The Champ thread below got me thinking about a Champ that had me flummoxed once. Amps dont get any simpler than a Champ so I felt a little dumb, not being able to fix it lickedy split. This was a early 70's Silverface Vibro Champ. The symptom was that the amp would power up and play normally for a few minutes and the sound would get scratchy (distorted like a poorly tuned radio) and start to diminish in volume until it was almost silent. A bad tube, right? Nope. A burnt resistor that stopped conducting? Nope. A cold solder joint? NOPE! I could literally find nothing wrong with this amp. So, we all know about the rca speaker connector on a champ - I had unplugged and plugged it in to break up any corrosion and there was no change. I find when I am at wits end over electronics (and I aint no expert) walking away for a day or two gives the "ol brane" time to think. The one thing I didnt do was to actually clean the speaker RCA connector - even though it was not visibly corroded. I cleaned it with some contact cleaner and brushed it (I keep old tooth brushes for this operation) and then used a q-tip. To my amazement, this was the fix. Still works fine today.