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Custom Cooling Rig- Transformer, Output Tubes

Discussion in 'Fisher' started by Linehand, Sep 29, 2018.

  1. Linehand

    Linehand AK Subscriber Subscriber

    Messages:
    104
    Location:
    Los Angeles, CA
    A590550D-2B33-4121-99F6-D93A39ADE9B1.jpeg 45398639-9E81-4CB3-B30D-CCFD2F767C95.jpeg E88A0C18-1932-48E3-82A3-51FF651D2AB7.jpeg Thought I'd share this setup with you guys. My (mostly restored) Fisher 800c was still running very hot after a few hours of use. Primary transformer surface temp was up to 145° and the output tubes were cooking the wall behind them...

    These fans have a temp probe lead which can be placed anywhere on the chassis to regulate fan speed and maintain steady temps. I have one probe placed in the center seam on top of the main trans and the second fan probe placed on the chassis between the output tubes and secondary transformers (just behind the heat shield transformer side).

    I'm still experimenting with placement, pardon the semi permanent rigging. In this position the fans run just above idle, stay whisper quiet, and everything (including tops of output tubes) is barely warm to the touch, even after several hours of use.

    I have tested these off a 12v battery and a wall wart. Neither are inducing any noise as far as I can hear. I'm currently on the wall wart, which I ripped off my son's fish tank and included a switch and LED (RIP Finn the beta fish)

    The fans are Arctic F12 TC and are pretty inexpensive peace of mind. I didn't find anything like this searching the forum so I figured I'd share.

    Man I love the sound of this Fisher...
     
    bobva and restorer-john like this.

     

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  2. Tom B

    Tom B AK Subscriber Subscriber

    Messages:
    1,490
    Location:
    Bay Ridge, Brooklyn New York
    Very nice idea. I may try them sitting above the screen of my unit which is in a fisher wood case. I wonder to how they would look inside a similar looking wood cabinet (As with the fisher cabinet) and just placed in the back over the screen.
     
    Linehand likes this.
  3. thornev

    thornev Well-Known Member

    Messages:
    557
    Location:
    Mid Hudson Valley, NY
    I have one 120mm fan that has a magnetic bottom pointing right at the tubes. It's plugged into the rear socket on the 500-C that is switched on with the unit. Heats the room in the winter too!
     
  4. Linehand

    Linehand AK Subscriber Subscriber

    Messages:
    104
    Location:
    Los Angeles, CA
    That'd be sweet, maybe mounted on some kind of isolation to minimize vibration...
     
  5. restorer-john

    restorer-john Addicted Member

    Messages:
    6,522
    Location:
    Australia
    Very cool. :)
     
  6. bobva

    bobva AK Subscriber Subscriber

    Messages:
    449
    Location:
    granite falls washington
    I would think you could have issue with your fisher. My 500B the 7591 run about 200-210 degrees. I can always hold my finger on the transformers. The fans may a mask to hide a potential mishap.

    I do like the fan. I now have a fan on my my X 202 B but thats a different animal,

    paste & copy. from dcgillespie

    The biggest reason that the X-202B runs hotter than a Fisher receiver is simply due to the differences in real estate: There is simply more room on a receiver chassis than on the X-202B chassis. Yes, the receiver has more tubes, but they are small tubes, and spread out more. On the X-202B, the power tubes are located down in a channel, while fully exposed at the rear of the receivers (except the earliest 500Bs). Also, and most important, the case is taller for the receivers, whereas for the X-202B, there is little overhead space at all with the cabinet installed.

    Mine is not in a cabinet but still.
     
    Last edited: Oct 1, 2018

     

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  7. Linehand

    Linehand AK Subscriber Subscriber

    Messages:
    104
    Location:
    Los Angeles, CA
    I thought there might be an issue as well, that's what led to the rebuild.

    On good advice from several members who helped through the rebuild, 145° is not too bad. That was after 6-7 hours of steady playing on 123-126v circuit.

    Usually I don't run the stereo that long, but now I don't feel so guilty if I do ;)

    Generally speaking, excessive heat is the enemy of any electrical component
     
    Bill Ferris likes this.

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