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Need help with EA-28RVT Epiphone

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  • Need help with EA-28RVT Epiphone

    I have a Epiphone EA-28RVT pathfinder, The volume control will not work the only way I can adjust the volume is with the reverb control ( reverb is not working )
    I thought there was a bad tube so I replaced all tubes with new ones , still the same thing.
    I can not fiend any popped caps of burnt resisters. I does not look like any thing has been rewired; I even swapped Reverb tanks no change, would you have any idea of where to look next, I can upload pictures and schematics if needed.

    Thanks,

  • #2
    Check the volume control side of C23 (V2) for Volts dc.
    There should be none.
    It may be 'leaking', which would explain both symptoms.
    Attached Files

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    • #3
      Originally posted by billyd View Post
      I have a Epiphone EA-28RVT pathfinder, The volume control will not work the only way I can adjust the volume is with the reverb control ( reverb is not working )
      If you have an original schematic with you amp, please scan and post. This amp is the Epiphone version of the Gibson GA-19RVT, and there were two different layouts of that amp. So, two different schematics. And, it wouldn't surprise me if they didn't do the same with this amp.

      Something puzzles me, in that the Reverb volume works. And by the schematic, that is on the front end of the Reverb circuit. If the Reverb doesn't work, how does the volume for it work? Makes me think that the Main volume and the Reverb volume are swapped.

      If you are able to read your schematic, you can trace each volume pot back to it's origins. Particularly, is there a 100K resistor (R20) between the wiper of the Main volume and V2-pin8? That will verify the Main volume is wired to the schematic that JPB posted. Then check to see if the wiper of the Reverb pot connects directly to V1-pin8. This will verify the wiring for that pot.

      I have posted a schematic of a later GA-19RVT, just in case yours has this configuration. Does yours have the 6C4 tube in the V3 position? Or, the 7199 in the V2 postition. This will get us on the right schematic.

      Jack
      Attached Files

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      • #4
        pictures

        Thanks for The help
        Frist off from what i can tell EA-28RVT is what I have here are a few pictures of the inside of the amp.
        The one pic has a Pencil pointing at what I think to be C23 please tell me if I am right or not, I did not get any dc volts,
        I do wonder if the pot’s have been rewired, I am just not that grate at following the schematClick image for larger version

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        I recheck the reverb unit it is working some .But like I said when turning the volume knob there is nothing I tested the POT with a ohm meter the Pot is good on both the volume and reverb.
        Click image for larger version

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ID:	827761Click image for larger version

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        • #5
          This one does use the 6C4 tube in the V3 position below I loaded some pictures, I am lie you I think that the pot's have been rewired , I checked both with a meter an both are good,

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          • #6
            yes the wiper of the Reverb pot connects directly to V1-pin8

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            • #7
              after looking closer R3 is wired to pin 8 of V1, and R2 is wired to pin 8 of V2 I think this is back wards I am going to switch these 2 and see what I get, I all so see a glob of solder from where the grounded shield wire from the foot switch, will clean that up an go from there. If any one thinks this is the wrong approach please let me know. below is a picture R2 is to the right R3 the left tone is the middle pot.

              Click image for larger version

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              • #8
                did you see the pic i uploaded, have any ideas on what i might do to fix?

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                • #9
                  did you see the pic i uploaded, have any ideas on what i might do to fix

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