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My brother called me up last week and said he had something that I needed to see.
Turns out he bought a storage locker with a Fisher 500c in it.
He said he plugged it in and a bunch of white smoke came out of it and it blew a fuse. Since he already has my old 500c he said, "give me $50 and it's yours." DONE!
I brought it home and pulled the bottom cover off of it and immediately noticed that it had been rebuilt at some point because it had Illinois capacitor coupling caps and electrolytics. Upon further investigation it was apparent someone had cobbled a couple of resistors in series to valve 9.
The resistors were noticeably burned and were the wrong value. Could this be the source of the white smoke? A 1.2k 10 watt wire wound should have been there (Thank you Mike Samra). Someone also rigged a toggle switch for the on/off as the detent on the volume no longer worked.
The power tubes are a combination of JJ 7591s, and one old 7591a. I'm guessing this not a matched quad.
Now for the good part; Nine made in West Germany Telefunken smooth plate 12AX7's that test very strong - Yipee Yahoo!
........I was a vegetarian for 15 minutes... until the main course.
Follow Ups:
I paid $50 for my first 500c......in 1997.....
And you have a rare first series 500c.....large dial version. Look at various pictures and you will understand. Your receiver should have the famed golden cascade FM section rather than the later and more common nuvister version.
Enjoy !
I am away from home on business at this time so I can't say with any certainty which version I have.I do believe it has nuvistor(s) though. It has a gold colored sticker that says "golden syncrode", and the serial number is 43XXXJ. I included a pic of the sticker that you may be able to blow up.
For now I plan to replace r121 thru r124 with 200k resistors, change the coupling caps from .047uf to .1uf Russian PIO's, put a new on/off rocker switch on the side of the chassis, replace a few of the non essential Telefunken 12AX7 tubes with cheaper tubes, and source a matched quad of the new Tung Sol 7591's from Jim McShane when they become available.
I plan to roll the Telefunken's in my Sherwood S-5000 when I get it back from Mike Samra just to see if I can take it up another notch.
I was a vegetarian for 15 minutes, until the main course.......Meat; It's the right thing to do. Romans 14:2
Edits: 10/13/14
Look at the array of pictures in google image for the 500c and the visual difference will be apparent.
Golden Cascode is the name Fisher used for their FM section.
Nuvisters look like very small thimbles- much much smaller than tubes. Did you pull any 6dj8 or 6922 tubes out- these would have been used in the FM section.
Best. Ross
Nuvistors.
See pic above.
I was a vegetarian for 15 minutes, until the main course.......Meat; It's the right thing to do. Romans 14:2
Have fun with it; a little tlc and you'll have yourself a dandy receiver!
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