I've restored a Danelectro Viscount amp. It was built in 1957, and sold then for $110 (that's about $831 in 2007 dollars). Here's the catalog page for this: Danolectro 1957 catalog page. I also mapped out the circuit, as I could find no schematic for it. The circuit is a bit unusual in that it uses a triode-connected pentode for the first stage and another pentode for the tremolo. The tremolo is quite lush. Danelectro Schematic. The layout is also a bit odd, as the input jacks, controls, and first stage are outside the chassis. The first stage has a shield that I removed for these pictures.

It really had only one problem: drifted resistors. Several were way off in the grid circuit of the first stage, and gave the amp a loud hissing noise. Two are off in the PI as well. I replaced the first stage resistors, but left the PI alone as the drifts “canceled” each other out, and it sounds OK as is. You can tell by picture four below that changing components in the main chassis would be a daunting task, as they really scrunched things together.