CKDC; The 500c is fairly simple to rehab and CAN be done by someone who has a basic knowledge of mechanical and electrical systems. You'd be replacing about 30-35 individual capacitors, (The can's included) and some power resistors, diodes. Testing the resistors in the unit can and will be time consuming AFTER you take the initial Voltage Readings. LABOR is the biggest cost in ANY electronic rehab/restoration. A compete set of parts (metalbone kit, CAN CAPS, upgrade parts(mainly resistors)) will set you back about $220.00. As for installing these, it's an 800C WITHOUT the AM Band tubes, and circuits. Tuner alignment is recommeded to be sent out . There are some shops around the DC area that can do an alignment for btwn $100. to $175. or so. None of the shops are fond of doing complete restorations as they end up tyig down a tech for 10-12 hours and it's nt a profit maker. These shops live on turnaround. So don't expect prices less than $700-800. at minimum.
Learn the hobby, and learn how to do it yourself. There are quite a few threads in the Stickies that pertain to the 400-500c-800c and all operate basically the same way. Parts are numbered differently from model to model, but that isn't a deal breaker. Ask questions of the group, and you'll get more and better responses than you would with ANY SHOP. We aren't here for money, were here for the love of the units, be it a mono tube amp, a mid 60's hybrid each, Multiplexers, etc. Most of us have at least 4-5 units that we've rebuilt/rehabbed/restored ourselves.
12ax7's start at about $12.95 for JJ's and run up to $50. each for Mullard Re-issues. These are all Russian tubes. You can scarf NEW Sylvania's from ABCVACUUMTUBES for about $15.00 each (These are NOS tubes and in original boxes, you have to specify Sylvania's). Fisher switched from Telefunken tubes to Sylvania's about 1966 when they were switching over to Solid State. The rest of the small signal tubes (for the tuner run btwn $3.00 to $6.00 each). If you want Old Stock Westinghouse tubes (generally used and unknown condition figure on $50-75 each to up to $200-250 for NEW OLD STOCK from some dealers. The EH7591's and TungSol 7591a Russian tubes are a good sub (and all I use with very good results in all my 7591 rigs) Run btwn $90.00 a qad for EH's and about $140. for the Tungsols. The big advantage to the Tungsols are the glass size. Same as original 7591 by Westinghouse. The EH's have a larger envelope. Either is a good choice for the 500c with caveats (this goes for all NEW Russian 7591's and is good for old tubes too). Screen Stability Resistors, Cathode Resistors, and the BIG one. Changing the value of the output coupling caps from .047uf to .068uf with concurrent grid return resistor value change from 330K to 220K. The outout tubes in FISHERs are ride hard and put away wet (overloaded at all times.) These changes will bring the tubes down into the SOA (Safe operating area) of the tubes as designed by the tube manufacturers, Which most all audio manufacturers threw out with the baby;s bath water when designing these unit's. Adding an IBAM or IBBA board (Individual Bias or Bias Balance bards) will allow you to adjust the bias of the tubes from running at the ragged edge of dissipation to a easier running 70% to 80% of maximum dissipation will lengthen tube life and still give you a very good sounding unit with the ability (with at least semi efficient speakers) to rattle the neighbors windows, provided the houses are less than 8 ft apart.
Manuals for the 500c are available on
www.fisherconsoles.com, and HIFIENGINE.com. The 500c doesn't have as many manuals as the 400 or the 800c so get the one that is closest to your Serial #. Also Check
www.akdatabase/AKVIEW.org (copy and paste exactly as written).
On the general forum, DIY Forum, and Tbe Forum there are stickies that you should read and study. Also 800c threads can be studied as 99% of the circuits are the same or similar. AGAIN ASK QUESTIONS! Nothing is too DUMB....(Well maybe a few, but we won't gig ya for them either.) If you get stuck on something, ASK QUESTIONS and POST PHOTO's.
Save yourself the aggravation of leaving at a shop and them not doing a complete job(most shops don't do the upgrades, or mods)that we do to our rigs here. All upgrades and mods are designed, tested on test mules, and proven with 100's to 1000's of hours on them. They run cooler, have had the output tube life extended, and are reliable as all get out. Plus if you do the work yourself you get BRAGGING Rights to tell your friends that you DID IT yourself. Even if you can't tell one end of a soldering Iron from the other. (Better learn this one fast or you'll end up with burned fingers or hands.
We've all BTDT at one time or another, so you're in good company.
1st thing to do is
NOT PLUG IT IN and TURN IT ON. Flip it over and take the bottom cover off. Then take an overall picture of the undersides, and 4 views showing each quarter of the undersides close up. This would help us determine if your 500c is a shop virgin or what's been done to it, and allow us to figure out what you need to do.
A topsides pic is useful too
For a Novice the 500c should take 2-3 weekends to completely rehab it minus the alignment, but it'll be 99.999999999999&4/10ths done.
So lets see some pics and we'll get ya started.
. HOWEVER QUESTIONS are ALWAYS ALLOWED!
And HIGHLY ENCOURAGED! (Remember the only DUMB Qustions are the one's you DON'T ask!
) That's how 99% of us here learned how to work on our stuff. So put another receiver in the system and listen to it
while you work on the 500c. More bang for the buck.
And most of us pass on what we've learned. It's not a problem if you hit a wall and get stumped. You'll hit a wall that many of us have hit and the solution is at hand just by asking. And you'd be surprised at how relaxing it can be while you have another system running in the background. 
