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I zapped my subwoofer with static electricity

H

Hangglider

Jan 1, 1970
0
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
 
J

John Popelish

Jan 1, 1970
0
Hangglider wrote:
(snip)
If I plug in the unit, I get a hum and that's it. (snip)
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

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.
 
H

Hangglider

Jan 1, 1970
0
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
 
Hangglider said:
I actually looked up the part number and it is DigiKey part number
LM741CNNS-ND.

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
 
H

Hangglider

Jan 1, 1970
0
Wicked cool. I had one already. I swapped out the op amp...FIXED!

Thanks guys!
Joe
 
J

John Popelish

Jan 1, 1970
0
Hangglider said:
Wicked cool. I had one already. I swapped out the op amp...FIXED!

Thanks guys!
Joe
Congratulations!
 
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