Car Amp Chassis + 12 Vdc

Discussion in 'The Projects Forum' started by colman, May 25, 2010.

  1. colman

    Thread Starter New Member

    May 25, 2010
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    I have an older amp that I have used in the past. It's a craig 260 W 4 channel. I do not know the model at this time. I mounted it to the chassis of the car in the trunk and it did not have any output to speakers. I read the manual and it said not to mount to chassis.

    Anyways my problem at this time is the Chassis of the amp to chassis of the car is +12Vdc. So it looks like something is blown in the amp to make the chassis hot or +12Vdc as the power wire fuse blows when I connect up the ground of the amp to the chassis of the car.

    Any Idea on what the parts I should look at the fix issue. Power supply ?
     
  2. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    start by opening it up and check for loose/broken/frayed internal wiring... That might be all it needs is to fix the short.
     
  3. colman

    Thread Starter New Member

    May 25, 2010
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    I already have and no physical wiring loose or burnt parts (visiable or smell). Everything looks fine. I am wondering if the problem would be on the power supply section of the amp.
     
  4. BMorse

    Senior Member

    Sep 26, 2009
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    What kind of car are you connecting this in? Some imports use a positive "grounding" system, so if you are trying to ground the amp via the chassis, you could be putting 12 volts into ground and power on the amp, hence why the chassis of the amp is getting hot....

    B. Morse
     
  5. colman

    Thread Starter New Member

    May 25, 2010
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    No it's a 04 Grand Prix which has a negative ground (I believe anyways).
     
  6. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    You need to figure out how the voltage is making it to the chassis of the amp.. It has to be something visible. Take pictures and post them if you can't figure it out...
     
  7. BMorse

    Senior Member

    Sep 26, 2009
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    Yeah, pics would definitely help!

    B. Morse
     
  8. bobdole369

    New Member

    Nov 5, 2009
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    Quite likely to be a dead short from the FET finals to the chassis. Typically large FETS have a large conductor which is the main heatsink area - common to one of the terminals. THe primary mode of failure on most consumer level amps is a shorted output FET. This puts the power supply of the amp on the chassis, which would normally immediately blow a fuse somewhere. Take her apart and find and fix the shorted FET.
     
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