My Park G10R practice amp stopped working. Specifically, the amp turns on, and if I turn up the volume, I can hear a buzz. However, when I plug my guitar into the amp, no sound comes through.

I know almost nothing about amps, but I figure the amp is worth less than the cost of a repair shop looking at it.

Here are shots of the internals. Is there anything you can see that might help me debug?

Thanks.