it powers up but theres no damn sound! when i move the rotary switches i hear an electronic "thump" through the speakers but no sound from the tuner at all, not even an electronic hiss. i pulled the speaker fuses and checked them with a continuity buzzer and they all checked out ok. Mark, could this be something simple? i know nothing at all about electronics, i can do replacement of components, i learned that as a freshman in high school. my old sony reciever bit the dust so if i can get this fisher working i'd be happpy as hell.
Bucky:
If it's been sitting a long time, there could be some light corrosion on the switch contacts (like where it goes from AM to FM to LINE, etc.). This is VERY common. The first thing I usually do with vintage switches: operate them about 50 times, end-to-end. The wiping action is often enough to clean off the contacts: many were designed that way on purpose so the contacts would keep themselves cleaned from operation. Real bad cases might need a little cleaning help: use "tuner cleaner" or "potentiometer cleaner" if you can find it, the clear stuff (in aerosol cans). After cleaning, a very light drop of oil will keep them happier.
The Fisher was one of the first to have the MUTE function, too. This squleched at audio until the proper "channel" selection was made so the "thump" you're hearing would not damage the (then new technology) low-travel woofer cones. There was a short delay of about 1 second when switching from one mode to the next, where the sound would be muted and then ramp up instead of slapping the amps (in case they were turned way up).
On many of the early Fisher quads they had aluminum or chrome selector and volume knobs (does yours?). These had one major drawback: static electricity from a walk across the carpet, transmitted to the selector switch or volume knob, would damage the mute transistors and shut off the sound. The most common symptom: if the volume was turned all the way up, you could just barely hear some music coming through. If yours has this particular problem, simply clipping off the collector lead of the mute transistors (there's 4 in that one) will let the sound through again. (They just shorted the signal to ground.)
Fisher wasn't alone in this problem: it was almost universal in the 1970s and early 1980s...I paid off my divorce bills by fixing "brand X" stereos "on the side" while I worked for SONY for 9 years.
