Ampeg SVP Pro power issues

Discussion in 'Amps [BG]' started by THE DANiMAL, Oct 20, 2013.


  1. THE DANiMAL

    THE DANiMAL

    Joined:
    Nov 22, 2007
    Location:
    Bartlett, IL
    So I just picked up an SVP Pro from t buddy, sounds killer except it randomly shuts of for like 30 seconds after just a few minutes of playing. Any thoughts on what could be causing this?
  2. cableguy

    cableguy

    Joined:
    Jun 4, 2009
    Location:
    North Bend, WA
    Does the power shut off (lights) or just the sound?
  3. THE DANiMAL

    THE DANiMAL

    Joined:
    Nov 22, 2007
    Location:
    Bartlett, IL
    Oddly enough, no sound, no lights, but it's still on, tubes stay lit and there's still power running.
  4. THE DANiMAL

    THE DANiMAL

    Joined:
    Nov 22, 2007
    Location:
    Bartlett, IL
    So when it shuts off, if I tap it, it turns back on. No joke, I can tap it anywhere and it'll
    Turn on. It also crackles when I tap it.
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  6. bassgod0dmw

    bassgod0dmw Supporting Member

    Joined:
    Mar 1, 2007
    Location:
    White Plains
    Pull the top off and check the ribbon cable that connects the two boards inside of it. Make sure it's well connected on both ends.

    It's a really crap design and falls out quite easily with nothing to really hold it in place.
  7. THE DANiMAL

    THE DANiMAL

    Joined:
    Nov 22, 2007
    Location:
    Bartlett, IL
    Yeah, the ribbon is fine, I just took the back end out to check for bad solder joints, it's all good. My guess is something on the front end maybe? My initial thought was tubes, but they're all good. I did a fresh swap earlier today to try to fix the issue. I almost feel like it's a ground issue, why else would the front end and sound go out and then kick back in when I tap it?
  8. Envincibal

    Envincibal Supporting Member

    Joined:
    Nov 22, 2008
    Location:
    Philly, PA
    I had something similar with mine and it turned out the be a bad/cold solder joint - easy fix (make sure the power is off when you fix it and unplugged)
  9. THE DANiMAL

    THE DANiMAL

    Joined:
    Nov 22, 2007
    Location:
    Bartlett, IL
    Hopefully I can tear it apart today and find out what's going on. The more I play around with it trying to diagnose, it's more apparent that its a solder issue. It cuts out after a certain amount of time which is really it shutting off at a certain temperature. So it makes sense.
  10. B-string

    B-string Supporting Member

    Joined:
    Nov 21, 2008
    Location:
    Lake Havasu City, Az USA
    A small wooden stick is useful to tap/wiggle lightly on components or gently flex pc boards when looking for intermittents. Hopefully is is not the HV winding on the power transformer.
  11. THE DANiMAL

    THE DANiMAL

    Joined:
    Nov 22, 2007
    Location:
    Bartlett, IL
    I found some bad solder joints on the transformer, I resoldered all the connections from it to the board. That seems to have been the problem. I ran it for a little bit with no issues. I'll give it another run tomorrow to make sure everything is good. Thanks to everyone that gave input. You guys helped me figure it out quickly!
  12. B-string

    B-string Supporting Member

    Joined:
    Nov 21, 2008
    Location:
    Lake Havasu City, Az USA

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