Tapehead Electronics in Austin.
Took in my 70's Pioneer SX-850 to figure out why it would lose the lower frequency signal intermittently along with a noisy volume knob. The fact that it spent most of its life in a barn didn't help, but it also did not kill it. They did replace a few parts and clean the entire inside of the unit and has since worked flawlessly, including the deposit which was applied to the final invoice, the cost was under $200. I have cleaned the outer shell, repainted the rusting metal covers, sanded and stained the exterior wood and now looks like a retro piece of furniture that produces amazing sound.
I did check a few other places in Austin and the estimates ranged from $500-$$800 depending on the scope after they get into the project. Mostly these guys are looking to refurbish the unit and the money can be considered well spent if that is what you're into. I just wanted it to work again and am very happy with the result. Also, I think it was less than a month when I got the receiver back, a full restoration would have likely be months longer.