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Old Marantz 250M amp

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  • Old Marantz 250M amp

    Hi all!
    Years ago I had an old Marantz tube amp repaired by a local guy who had a workshop in his basement somewhere in the Albany/ Clifton Park area. He did a wonderful job, but I lost his name/address. I wonder if anyone here knows of this person. I believe I found him on a forum way back when.
    I have a Marantz 250M amplifier. When it is switched "on", the circuitry goes into some kind of warmup mode and 10-15 seconds later, a relay kicks the system "on".
    For the past year or so it has taken longer and longer to kick in. Once one, sometimes one or both channels disappeared, then came back. Now, however, the relay is not kicking over any more, no matter how long I wait. I opened it up, tightened the nuts attaching the wires to the main caps, wiggled things around, but could find nothing obviously wrong.
    Firstly, any suggestions?
    Secondly, do you know of anyone local to me (Albany, NY area) that is competent with 1970's era equipment?
    Thanks for your help.
    Wolf

  • #2
    amplifier

    the only thing I can figure out is that the relay coil is in series with the filament string. Each tube has a filament that directly or indirectly heats the cathode. more than likely it operates at about 6.3 volts. if you have a burn't out filament in one of the tubes, the relay will never come on because it is in a series string. check all the tubes for an open filament. also, a short in a tube may present a higher than normal voltage to the relay and you may have burnt up the relay coil. for a service guy I have no idea. check the yellow pages. I'm looking for someone that can service a mosfet karaoke amplifier I have. Nobody wants to touch it.

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