Amp tipped over in truck: no reverb!

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by achtung, Jun 27, 2006.

  1. achtung

    achtung Member

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    Hi all,
    My name is Chris. I'm a newbie and my amp don't work...
    Actually it's the reverb that is out. It tipped over in the truck on the way to a gig and that was enough to do it. My tech thought it would be the tank but I ran a small marshall thru the tank and it sounds great. What would be the next thing to look at? It's a vox ac15 (korg re-issue), tube driven. I have the schematics but don't really know how to read them (yet). any help would be appreciated.

    Chris
     
  2. brad347

    brad347 Member

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    try swapping the reverb tube. Then check the solder joints on the reverb input and output jacks (if any)
     
  3. Swarty

    Swarty Member

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    90% chance that one of the connections to the jacks on the inside of the tank broke.
     
  4. mbratch

    mbratch Member

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    I agree. The wires inside the tank are generally fine guage and break easily with severe shock. Take the tank out and look at it closely.
     
  5. Dave Orban

    Dave Orban Gold Supporting Member

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    That would be the first place I'd look, too.
     
  6. donnyjaguar

    donnyjaguar Member

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    I think I'll design a device that will park the reverb springs during transit. I'll then patent it and sell to Accutronics and retire early. I'll then write my memoirs and pontificate about how hard I worked to get where I am today. :)
     
  7. brad347

    brad347 Member

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    but guys, he said another amp plugged into teh reverb tank worked fine.
     
  8. achtung

    achtung Member

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    thanks brad for grabbin the reins! Yes, reverb pan is good. I searched and found feedback from you guys about a princton reverb with a similar problem. My tubes just checked all ok (I swapped the 12ax7 reverb send tube and return with known working tube). Now where I'm at is unplugging the damn circuit board and getting a peep on the other side so I can see if a solder j is lame. I guess I just push in the white plastic holders after I unhook a few wires and knobs...what a drag man. You guys with your oscillascopes don't know how intimidating this is. On another cir. board there is the reverb tranny (a little dinky thing) If I have to test that I may need a pointer (or stern warning maybe).
    anyway, thanks for the input!
     
  9. Tuberattler

    Tuberattler Member

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    If you've tested the tank and it's good and you've confirmed the tubes are good next take a look at the cables, it's pretty unlikely that something got damaged on the board.. have a second set of eyes look at it with you. REMEMBER there are dangerous VOLTAGES inside your amp even when not plugged in or turned on.
     
  10. achtung

    achtung Member

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    tuberattler, yes that's where I am. rca cable is good. I checked res and swapped out with a good cable. The next place I guess is something amiss on the board. I figure I can atleast dismount the board and check before I give up.
    I can say that when the reverb is clicked on and I have the master turned up halfway (loud) it makes a faint howl that creeps in after about a second of hitting the button, kinda like a '50's sci-fi effect, then hit the reverb pedal again and it instantly stops, hit it again and it's "something in the deep"...yep, it's something allright.
     
  11. trdlasvegas

    trdlasvegas Member

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    When sorting out a reverb problem one of the first things I do is smack the amp with the reverb pot turned up. If you hear "all hell breaking loose" like when you trip over your amp with the reverb turned up, then you know the Reverb return is working fine, and the problem is the drive to the tank.

    Helps to narrow down the problem a little.

    -Tony
     

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