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Thread: Peavey VTM 120 - No Power to Preamp & Power Tubes - ON/OFF & Standby Cables Fried

  1. #1
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    Peavey VTM 120 - No Power to Preamp & Power Tubes - ON/OFF & Standby Cables Fried

    So my Peavey VTM 120 was working fine on Friday, but I went to turn it on Sunday morning and it wasnít making any sound what so ever. Both the ON/OFF switch light up but there is no glow on either the preamp or power tubes. The tubes are relatively new so I donít believe they are the culprit, or at least are functional enough to glow.

    After doing some research many have noted that the internal 8 AMP slow-blow heater fuse could be the culprit so I opened up the chassis to replace the fuse. Upon doing so I noticed that the 2 wire connections from the ON/OFF and standby switches were fried (see the picture below). I checked all the fuses and replaced the ceramic 8AMP heater fuse for good measure. I opted to not go any further since something obviously was sending more juice than necessary to the switch connections and I didnít want to cause any further damage. If anyone could shed a little light on this if they happen to have and ideas of what may have caused this it would be greatly appreciated. I do have some great repair shops around me but I was more curious to put it out there before bringing it in incase this could be something simple. My understanding of electronic isnít the best but my ability to solder and repair electronics is solid. I build guitars and wire things all the time, Iíve also built a couple PSBís etc.

    Thank you in advance! -Steve





  2. #2
    Supporting Member Jazz P Bass's Avatar
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    Here is the schematic & layout for that area of the board.

    peavey-vtm-60,-120_ J2 J3.pdf
    peavey-vtm-60,-120_ J2 J3 Layout pdf.pdf

    Overcurrent draw may have caused the failure as well as poorly soldered connections underneath the board.

    I am confused by (what the layout diagram terms 'J3") the 3 wire connector.
    The layout shows a two wire in that location.

    Your photo does not show J1, which is a three wire.

  3. #3
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    Not sure if this helps but it look like the 400/10W (R5) resistor is what got hot and fried the connections. J3 I believe is the ON/OFF and J2 is the standby. I wish I took more/better pictures.


  4. #4
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    NOTE: This is NOT my VTM but is a better angle for reference it that is at all helpful.


  5. #5
    Senior Member Enzo's Avatar
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    Your standby switch connector burnt up its pins, probably they lost contact and arced.

    Check your 400 ohm resistor for opens. A shorted screen node on the B+ would burn up that resistor.

    Look on the Xray view of the board to see where the traces go. I would just remove that connector, and solder the wires direct to the circuit. In this case the left end of the 400 ohm and the other to the + end of C3.
    J M Fahey likes this.
    Education is what you're left with after you have forgotten what you have learned.

  6. #6
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    Thanks for the insight guys! I guessing I'll probably just bring it to a tech seeing is there are probably more variables than I can personally troubleshoot safely. I've never taken it in after owning it so it may be a good plan just to have it "tuned up" anyway.

    thanks again, Steve

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