Fender Rumble 100 amp

[Den.]

Hi. My friend's Rumble 100 bass amp suddenly, overnight, has developed a problem and I have been asked to troubleshoot it. The sound with a bass or guitar is totally distorted and loud, and this distorted sound exists with ALL of the controls set at ZERO. I've attached an MP3 file of a few seconds of strumming a guitar plugged into the amp. I have already tried disconnecting the internal speaker and hooking it up to my guitar amp and it sounded fine. I opened the amp up and all I found that looked suspicious was a 10k resistor on the power supply that looked like it had gotten hot and was leaning against a .33uf safety cap (I've since straightened it up). Both components tested good in circuit, well within tolerance, and they also tested good, well within tolerance, after I removed them from the board. Where do you suppose that I should start looking next?

[dmeek]

Possibly a bad Volume pot R11 or cracked solder connections on this pot.

[Den.]

Possibly a bad Volume pot R11 or cracked solder connections on this pot.

Thanks, but on this board R11 is an SMD component. I'll inspect the master R134, gain, drive and level R23, R51, R68.You cannot view this attachment.

[dmeek]

Sorry, I was looking at the V1 schematic. This  is V3, a lot different, though  still suspect a bad pot.

You cannot view this attachment.

[Den.]

...yep, it was the Master Volume pot; the first one I measured. It's an A500K and it measured in the millions and fell apart when I removed it. Thanks for the suggestions! You cannot view this attachment.