Tweed vibrolux troubleshooting

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by angusfan, Nov 21, 2013.

  1. angusfan

    angusfan Member

    Messages:
    118
    Joined:
    Aug 20, 2007
    Location:
    Nebraska
    I have a 57 vibrolux, it worked fine. I took it with me out one night to play, worked just fine. I was careful moving it around. Now its have a problem.

    You can hear it humming, but the power tubes Don't power up by the looks of them but the 5Y3 does. And the ploit light doesnt come on. No sound.

    Before I take it in to have it looked over, is there anything I can check to see if it's just something simple?

    Thanks,
    Kory
     
  2. Blue Strat

    Blue Strat Member

    Messages:
    30,049
    Joined:
    Aug 2, 2002
    Location:
    Sterling, VA (not far from Washington DC)
    Is the hum heard through the speaker? The pilot light could be blown. Simple fix.

    Plug straight into the amp with just a guitar and cable. Try different guitars and cables. Make sure the speaker is plugged into the spkr jack.

    Do the power tubes get warm? Try different preamp tubes if you have spares.
     
  3. angusfan

    angusfan Member

    Messages:
    118
    Joined:
    Aug 20, 2007
    Location:
    Nebraska
    Hum isnt thru the speakers, you can hear the hum of the transformer. Power tubes dont get warm. I just put in a new pre-amp tube and it was working for a week or two. Cable and guitar is all I use, and have replaced both to see if that was the problem.

    Thank you for the info.

    So now power tubes, fuse is fine. 5Y3 lights ups. Pre-amp tube come to think about it, can't remember if it powers up. I will check that tonight. No pilot light,
     
  4. angusfan

    angusfan Member

    Messages:
    118
    Joined:
    Aug 20, 2007
    Location:
    Nebraska
    I would like some help if anyone can.

    No power tubes or preamps warm up. But RF tube does. No sound. Changed both preamps.
     
  5. WaltC

    WaltC Member

    Messages:
    2,129
    Joined:
    Feb 21, 2006
    Location:
    Northern CA (Sacramento area)
    if the pilot light doesn't come on and the power/pre-amp tubes don't light up, there is (at least) a problem with the heater circuit, they're all driven from the 6.3V tap off the power transformer, the rectifier (*not* RF) tube is powered from a different (5V) tap off the PT

    This is a valuable and great sounding amp (potentially at least) and it's sounds like it's time for a trip to the amp doctor.
     
  6. 76strat

    76strat Member

    Messages:
    410
    Joined:
    Jul 15, 2010
    Kory--you didn't mention whether your '57 has had a cap job and the other usual amp doctor visits/nosejobs, etc. Perhaps the real experts on here (certainly not me) can help you further if you give exact description on what has been done, what is original (as best you know, etc.), etc. I have a '58 quite similar to yours that had a noticeable loss of volume and nasty overdrive/fuzz imparted after about 10 minutes of playing. The cure was, of all things, a new fuse. The old one (perhaps original) had condensation in it, which I would have thought would have rendered it non-functional. My amp tech always thought that if the fuse ain't blown, it's still good. Not so. We also cleaned all of the pots and input jacks. You'd be surprised at how much help doing those simple changes will do to the overall product (as I'm sure you know). Problem solved for mine. Good luck with yours--they're great amps.
     
  7. TheAmpNerd

    TheAmpNerd Member

    Messages:
    1,057
    Joined:
    Sep 23, 2004
    Location:
    Tejas
    Bummer,

    + 2 What the other's have said.

    Worst case:
    Including, that power transformer is beyond the end of its useful life.
    The enamel coated wire in the transformer may have degraded to
    the point where the heaters no longer work.

    It may be time for a rewind or buy a new power transformer for it.

    Best case:
    There's always the possibility that one of the heater wires broke off
    at the soldered connection maybe at the lamp?

    Good luck.
     
  8. angusfan

    angusfan Member

    Messages:
    118
    Joined:
    Aug 20, 2007
    Location:
    Nebraska
    I got the amp repaired, it had a ground wire break on it. Along with a power cord that the amp repair man didn't like. We are rewireing the route of it.
     
  9. TheAmpNerd

    TheAmpNerd Member

    Messages:
    1,057
    Joined:
    Sep 23, 2004
    Location:
    Tejas
    that is good that it wasnt worst case. : )
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice