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  • Help with Pmh2000

    Hello I am repairing a Pmh2000, and after having replaced all the transistor of the power plate, and check diodes, resistors of the power part I still have 65 volts in one of the outputs, I also lack the voltage of +15, the of -15 if it is. The ICs 4580 and 3080 are damaged, because they are connected to +15 ?. Could you tell me where to go? Many thanks

  • #2
    For a start, carefully examine the schematics, compare the measured voltages with the schematic and replace the defective components.
    PMH2000 schematic is located here:


    https://music-electronics-forum.com/showthread.php?t=41121
    It's All Over Now

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    • #3
      More direct link to the schematic: https://music-electronics-forum.com/...6&d=1560185842

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      • #4
        Repair your power supplies before deciding ICs are bad. They cannot possibly work with one of their power supplies missing.

        The whole circuit cannot work without proper power supply. I can say that about ANY powered circuit.

        You can remove the 3080 and the amp should still work. Just a test.
        Education is what you're left with after you have forgotten what you have learned.

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        • #5
          In the scheme 3080, would be the Lm3080?

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          • #6
            I am sorry, I was being casual, and I shouldn't.

            Yes, the 3080 means the LM3080. It is used as a compressor, and if removed, the amp still works but loses the compressing function. That is it will no longer prevent clipping if over driven.
            Education is what you're left with after you have forgotten what you have learned.

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