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smoking transistor on a 15 watt combo amp

Discussion in 'Amps and Cabs [BG]' started by vectormane, Jul 7, 2001.

  1. vectormane


    Jul 10, 2000
    I recently recieved, for free, a broken 15 watt combo amp. The brand is Performance Plus, and the model number is gb12p. I would say the amp is over 5 years old. It hums, does not play, and smokes out of the input hole when turned on. The speaker, an 8 inch, works just fine when I hook it up to my other amp. Removing the head portion reveals that the smoke is coming from a 5 pin transistor that is attached to a heatsink. The chip has on it "MDA 2030". Following the path on the PCB leads me to a missing diode which I believe, based on the solder joints, is supposed to be there. What I need to know is:
    Where do I buy a new transistor?
    What type of diode, if any, should I use if I'm to replace the purloined one?
    Where can I buy said diode?
  2. The transistor you're referring to is actually an integrated circuit, in this case known as the TDA2030. Other brand specific type designations may show MDA2030. It's very common IC and should be available from Radio Shack or other micro electronics parts shop.

    You should try to determine if the diode was really in it. If the mftr did not put it there, there's no point in putting it "back". If there was a diode for sure, and someone trying to repair the amp soldered it out, I'm sure a 1N4004 or, if it fits, a 1N5404, should do the trick. Get it at Radio Shack.

    I hope this helps. Good luck!
  3. Mike N

    Mike N Missing the old TB Supporting Member

    Jan 28, 2001
    Spencerport, New York
    Unless you have a schematic for that amp,I wouldnt assume that a component is missing based on holes/solder joints in the board.Imo,Id take the amp to a repair shop.There could be more than a missing diode that caused the transistor to puke.

    If you still want to try fixing it yourself,any Radio Shack(if your in the US/Canada-you didnt fill in your profile)should have diodes and transistors in stock.They may even have someone there that can help you get the right diode for your application.

    Good luck.
  4. That 5 pin IC is probably just shorted. I don't think Radio Shock carries it. ECG makes a replacement, though.


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