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  1. bill-g

    Fisher 250T still cooking

    The Fisher 250T saga continues. The voltage regulator fix took care of the tuner drift and is holding just fine. The silver plated switches, especially in the Tune-O-Matic, were getting really problematic, and seems like Deoxit doesn't do much for them. I like Deoxit as a control cleaner/lube...
  2. bill-g

    Fisher 250T still cooking

    The Fisher 250T saga continues. The voltage regulator fix took care of the tuner drift and is holding just fine. The silver plated switches, especially in the Tune-O-Matic, were getting really problematic, and seems like Deoxit doesn't do much for them. I like Deoxit as a control cleaner/lube...
  3. bill-g

    AVA Ultravalve schematic?

    No, never worked for AVA, but did meet Frank briefly when I worked at Northstar Sound back in early 80's in my first tech job. Went out there to get some parts for an AVA amp that we had on the bench as a favor for a commercial sound customer. Fun to meet the man himself. I've never owned one...
  4. bill-g

    AVA Ultravalve schematic?

    Have sent a query to AVA, we'll see what they say. Cademan, power supply is a good suggestion, but been there, done that. Which is why I'd like a schematic. While it's based around a Dyna ST70, and I've seen a schematic for that posted here, Van Alstine has several lower voltage supplies in...
  5. bill-g

    AVA Ultravalve schematic?

    I'm helping a friend whose AVA Ultravalve just went dead, tubes glowing, B+ is there, a bit high at 460V. No signal out. Sort of guessing that a lower voltage PS has failed. He can't find his manual. Anybody know if Van Alstine included schematics in there, and does anybody have a copy they...
  6. bill-g

    The Idiot's Guide to Using DeOxit (revisited)

    JonWalter, the symptom you describe, of intermittent dropout at low volume, and recovery on turning it up, is a classic indicator of a dirty speaker protection relay. By all means, clean all the switches and controls with Deoxit or something similar, but you'll probably need to get the cover off...
  7. bill-g

    What is wrong with my tapes?

    Back in the late 60's, I learned a lesson the hard way. I left one of my reel to reel tapes on the desk for several hours next to a hi intensity reading lamp which had a transformer inside. The stray alternating field erased the hi freqs on the side of the tape closest to the transformer. and...
  8. bill-g

    The Idiot's Guide to Using DeOxit (revisited)

    No need to go nuts cleaning, really, unless you are doing some sort of beauty contest restoration. Most components don't have to dissipate any real heat. Power transistors and the heat sinks would be an exception. I use a paintbrush to dislodge loose dust without damaging anything, and the...
  9. bill-g

    Fisher 250T still cooking

    Bummer. Some folks don't get it, especially galling when they're friends or relatives. My wife would love it if I tossed all my good stuff and replaced it with some plastic Bose icecubes+subwoof. She paid about $300 for one of the Tivoli KLH reproduction table radios, but the tuning cap started...
  10. bill-g

    Fisher 250T still cooking

    Addendum: At some point I verified that the PS output to the Tune-O-Matic (ya gotta love that name) was drifting as the unit warmed up. Last summer I ran across a higher voltage 3 terminal adjustable regulator, the TL783, that can take much higher input volts (125v input-output) than the...
  11. bill-g

    The Idiot's Guide to Using DeOxit (revisited)

    Interesting idea, I get wanting to hack the system, but I certainly would not put olive oil in anything but food. Most vegetable oils oxidize and turn into a sort of gummy varnish over time. I do occasionally use naptha (white gas/campstove fuel) to clean parts, but I'm really careful with it...
  12. bill-g

    Fisher 250T still cooking

    32294, guess it's a T. Did you change the zener because it had failed or just in the spirit of preventive maintenance? I suppose what I should do is observe the regulated supplies with DVMs from cold start and try to see if there's actually any correlation with the tuner drift. I was looking...
  13. bill-g

    Fisher 250T still cooking

    I turned 62 today, and thought I should post a tribute to my Fisher 250T. Still using it as my main amp. Here, I'm guessing this is regarded as a sterling virtue, but by most other people as a symptom of pathology. Maybe this is changing though. Just think of all the hi-fi equipment I...
  14. bill-g

    Transit screwed!

    I guess in defense of the ordinary human users, I have to say that the mfr went to the trouble to stamp the instruction "oil" with an arrow pointing to the motor shaft, but didn't do a damn thing to suggest that those screws should have been loosened. They were lacquered sort of pinkish, but not...
  15. bill-g

    Transit screwed!

    OK, this is pretty funny. So, like 14 years ago, I got laid off my job, and rolling down the alley to my driveway, I found a Toshiba AR-270A turntable by a neighbor's trash can. Kind of a consolation present from the Great Magnet. All it needed was a new set of phono plugs installed on the...
  16. bill-g

    Deoxit?

    Thanks for info, dr audio. I'll have to fiddle around some myself. Haven't tried to use it on anything with a visible surface, just the innards of switches so far. Re Gold, from what I gather on Caig's site, it has less of the magic oxidation eating foofoo, and some protective lube. It...
  17. bill-g

    Deoxit?

    I hope this isn't the equivalent of restarting the dreaded oil or tire thread on a motorcycle forum that will get me booted out by the admin. Does anybody actually know what the active ingredient in Deoxit is, and how it works? Enough people seem to like it that I'm guessing it works for...
  18. bill-g

    The Idiot's Guide to Using DeOxit (revisited)

    Thanks for the tutorial on Deoxit, as the Caig's website is a bit hard to decipher BG
  19. bill-g

    STV-4H varistor

    Thanks! Echowars is kinda da bomb!
  20. bill-g

    STV-4H varistor

    Mine appear to be OK, but if they weren't, can one just make a stack of 3-4 silicon diodes, close coupled thermally, and bodge them onto the heatsink? The voltage I see with the VOM corresponds to 3 diode elements. Or was there more black magic in there than that? BG
  21. bill-g

    STV-4H varistor

    Am putting in the replacement parts in my SX-939. The varistors that attach to the heatsinks appear to be OK, but anybody know of a cross ref replacement device, or would I have to get that straight from Pioneer if it was hypothetically available? BG
  22. bill-g

    SX-939 rehab ??s

    OK, so it probably was a factory job. Would have been interesting to be a fly on the wall when it was being built. OK, well maybe not THAT interesting. What do you bet they ran out of silicone grease and didn't dare stop the assembly line? "Hey everybody, go home for lunch, and get your wife's...
  23. bill-g

    SX-939 rehab ??s

    Yup, lacquer as in hard and brittle. Must be flaky repair job. Have variac, will bring it up on that, monitoring AC current. On the other hand the dimbulb sounds like a good idea in case of surprises, in addition to the variac. I'll make one. Thanks, BG
  24. bill-g

    Receiver Blowing Speaker Fuse

    Actually just noticed the part about it happening without speaker being connected. Are the speaker wires completely disconnected too?
  25. bill-g

    Receiver Blowing Speaker Fuse

    Lots of DC coupled amps deliver a DC thump on turn-on as the amplifier settles. Most later models have the speaker outputs connected through a DC detection/protection circuit and relay that trips when it detects a DC imbalance. Since your amp has speaker fuses, it doesn't have that sort of...
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