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I zapped my subwoofer with static electricity

Discussion in 'Electronic Basics' started by Hangglider, Feb 6, 2006.

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  1. Hangglider

    Hangglider Guest

    I was at my office and a small spark of static electricity from my hand
    has killed my subwoofer. The unit is UNGROUNDED...I can hardly believe
    it, but it is. It has it's own power supply and a relatively simple
    amplifier. I intend to add a ground to the unit!

    If I plug in the unit, I get a hum and that's it. It doesn't matter if
    there is an input plugged in or not. Does anyone have any
    recommendations as to which components I should try replacing first?

    Here is a listing of the components on the board:

    Transistors:
    TRANS PWR NPN 10A 60V
    TRANS PWR PNP 10A 60V
    TRANS PNP GP 800MA 45V
    TRANS NPN GP 800MA 45V

    Capacitors:
    CAP 4700UF 25V ALUM ELECTROLYTIC RADIAL (2 for the power supply)
    CAP .47UF 50V ELECTROLYTIC KMG RAD
    CAP 470UF 25V ELECTROLYTIC SMG RAD
    CAP 10UF 25V ELECTROLYTIC SMG RAD
    CAP .0012UF 50V POLYESTER
    CAP .0027UF 50V POLYESTER
    CAP .1UF 50V POLY B SERIES

    Resistors:
    RES 4.7K OHM 1/4W 5% CARBON FILM
    RES 47K OHM 1/4W 5% CARBON FILM
    RES 220K OHM 1/4W 5% CARBON FILM
    RES 150 OHM 1/4W 5% CARBON FILM
    RES 100 OHM 1/4W 5% CARBON FILM

    IC:
    IC OP AMP HI PERFORMANCE 8-DIP

    Any advice is greatly appreciated!

    Thanks,
    Joe
     
  2. Hangglider wrote:
    (snip)
    The only one of those components likely to be damaged by static is the
    op amp. But you are going to need more information than you have
    given us to find a replacement.
     
  3. Hangglider

    Hangglider Guest

    I actually looked up the part number and it is DigiKey part number
    LM741CNNS-ND. It's pretty cheap. Actually, all the parts on that
    listing I looked up using various online sources and found all the
    parts at DigiKey. They are all pretty cheap. I actually thought about
    just buying all the parts and building a new one for the heck of it. I
    can get most of it for about 20 bucks.

    The only thing that was difficult to figure out was the "green"
    capacitors. They were marked 104J. I determined that this meant they
    were .1 microF with a +/- tolerance of 5%. I think they are "Polyester
    Film" because through all the digging and scrounging, they seem to be
    one of the few capacitors that have that tight tolerance and physically
    look like the ones on my board.

    Thanks for taking the time to reply!

    Joe
     
  4. Guest

    If you want instant gratification, you could get this at your local
    Radio Shack:

    LM741CN Operational Amplifier 8-Pin Dip Catalog #: 276-007 $0.99
     
  5. Hangglider

    Hangglider Guest

    Wicked cool. I had one already. I swapped out the op amp...FIXED!

    Thanks guys!
    Joe
     
  6. Congratulations!
     
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