Kustom Coupe 72 Tremolo/Vibrato Circuit Issues

Discussion in 'Glowing Bottle Tube Amp Forum' started by mosquitocontrol, Feb 26, 2020.

  1. mosquitocontrol

    mosquitocontrol TDPRI Member

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    I have a Kustom Coupe 72 and the tremolo/vibrato circuit stopped functioning. When I try to use it I get no sound out of the amp at all. Everything else is functioning normally. Does anyone know what would be the first area to troubleshoot? Could it potentially just be that the tubes need to be replaced?
     
  2. Wally

    Wally Telefied Ad Free Member

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    I do not know for sure and cannot find the schematic, but I am going to take a wild guess based on the number of functions and the number of 12AX7 tubes that the reverb and the tremolo are very likely to be in the solid state domain. I could be mistaken.
     
  3. mosquitocontrol

    mosquitocontrol TDPRI Member

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    I've attached the schematic. I'm not completely fluent in reading electrical diagrams.
     

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  4. ICTRock

    ICTRock Tele-Afflicted

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    looking at the diagram, I'll say the relay(s) that handles switching the tremolo/reverb in and out of the circuit is probably the culprit
     
  5. mosquitocontrol

    mosquitocontrol TDPRI Member

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    Which number relay(s) would those be?
     
  6. ICTRock

    ICTRock Tele-Afflicted

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    understand that I have reservations just outright answering your question. for one, I have no way to verify the accuracy of your schematic against the reality that is your amp's circuit board right in front of you ... moving past that, we have the issue of working on something you don't fully understand (correlating that which you see on paper to that which you see in front of you). I can give you a best-guess theory then you run with it and inadvertantly make things worse.
    my advice is to take it to a tech.
    now of course you are going to find this answer dissatisfying, so the answer to your question is relays 5 and 6 as notated in the output of the tremolo section, input of the reverb section, and the footswitch section of the schematic. again, this is no guarantee to be the root cause. I would verify voltages at the various labeled test points first and if those check out start looking at signal tracing.
     
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