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What is this?!?

Discussion in 'Amps and Cabs [BG]' started by enim, Oct 10, 2006.


  1. enim

    enim

    Jun 29, 2006
    Chicago, Illinois
    I am in the process of trying to fix (ever so nervously) my 1979 Peavey Century.

    As a thought, i took off on of 4 small plates, finding this guy underneith. On his top he says RCA 7901 and 62792.

    Any help would be great.

    Also, is taking this amp apart a bad idea???

    (clickable thumbnail
    ) th_HPIM04171.jpg
     
  2. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    Power transistor. Also, the plastic plates are integral to compressing the transistor against the case, which is the heat sink. Put those plates back on. They exist because the body of the transistor is at a high voltage. Also, you will note a thin slip of insulating material between the transistor and the case. This can be a bit delicate if you try to pull the assemblage apart. And there is thermally conductive goop in there as well. Put the plate back on.

    There should be 4 screws at the two ends of the back panel that release the entire panel. That's how my old Peavey head was. The front panel comes off the same way.

    As those transistors are part of the power amp, which you said works, they are not involved in your problem.

    Sorry to sound snappy with you. I just wanted to make sure you have the correct information before proceeding.
     
  3. enim

    enim

    Jun 29, 2006
    Chicago, Illinois
    Wow. Thank you. A lot. You didnt sound too snappy at all, very informative.

    Thanks again
     
  4. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    Also note that Peavey is renowned for providing schematics if you ask.
     
  5. Krischu

    Krischu

    Oct 10, 2006
    I'm not sure if someone already mentioned, but this power transistor is lacking one mounting screw (plus insulating washers/feedthrough).
    You should fix this since the transistor requires good heat contact to the metal surface underneath.
     
  6. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

     
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