euroticcustoms
New Member
My first post on here, thanks ahead of time for any help. I've got a CVM 500.1 car audio amplifier. 500 watts RMS at 2 ohms. It recently quit working, but wasn't in protect mode, so I took it apart to see if I could find anything wrong. The problem appeared to be a clearance issue between the board and case. There was a cluster of six 1000uF 80V capacitors in the middle of the board. They were wired in parallel I believe? 3 x 2 with the 6 middle leads going to the positive output of the amplifier. Anyway, one of the legs in this circuit was touching the case, burnt the paint off and arc'ed against the case. I called Radio Shack and the biggest capacitor they had in stock was a 1000uF 50V, which I thought about putting 2 in place of this 1, but decided to fix the problem at hand and go from there. I figured either A.) all the capacitors were fried due to shorting to ground, or B.) none of the capacitors were fried as this would be like hooking the a speaker wire to ground, hoping the circuitry of the amp may have prevented it from damaging anything.
Also worth mentioning...as I was taking the amp apart, I was removing the hold-downs for the MOSFETS and one laid over AGAINST THE CASE, not the board, and a static spark arc'ed off of one of the MOSFETS. I thought nothing of it, as I didn't even know what a MOSFET was at that point lol Anyway, I (as a temporary fix) tried lining the center of the amp with electrical tape. Put it all back together - the bottom cover to the amp which nothing connects to by the way. I re-connected all wires to the amp, turned the key on, radio on and heard the subwoofer kick once, then a pop, static through the speakers, then sounded like a sparkler or a book of matches going off in the back. I looked in the trunk and those mosfets were igniting one by one. Fried 5 of 8 of the small ones DEFINITELY. I shut the key off, but the power light stayed on on the amplifier until I quickly removed the ground wire. Still wasn't in protect mode, no blown fuses.
I'm an auto technician, decent with automotive electrical. I've seen the inside of a lot of electronics, but I know enough about them to get myself in trouble. The board APPEARS to be alright, as do all the other components on the board (capacitors, resistors, transistors, etc) none are VISIBLY damaged, no arc'ing.
What are the chances that a static arc onto a mosfet would cause 5 in all to self destruct? I can get the ones I need for cheap enough, just wondering if it would be worth the time/money? Or would there be an underlying issue that would cause the FET to go up in smoke?
I know how to solder and use a multimeter. Learn really fast. A push in the right direction would be great. Thanks again.
Also worth mentioning...as I was taking the amp apart, I was removing the hold-downs for the MOSFETS and one laid over AGAINST THE CASE, not the board, and a static spark arc'ed off of one of the MOSFETS. I thought nothing of it, as I didn't even know what a MOSFET was at that point lol Anyway, I (as a temporary fix) tried lining the center of the amp with electrical tape. Put it all back together - the bottom cover to the amp which nothing connects to by the way. I re-connected all wires to the amp, turned the key on, radio on and heard the subwoofer kick once, then a pop, static through the speakers, then sounded like a sparkler or a book of matches going off in the back. I looked in the trunk and those mosfets were igniting one by one. Fried 5 of 8 of the small ones DEFINITELY. I shut the key off, but the power light stayed on on the amplifier until I quickly removed the ground wire. Still wasn't in protect mode, no blown fuses.
I'm an auto technician, decent with automotive electrical. I've seen the inside of a lot of electronics, but I know enough about them to get myself in trouble. The board APPEARS to be alright, as do all the other components on the board (capacitors, resistors, transistors, etc) none are VISIBLY damaged, no arc'ing.
What are the chances that a static arc onto a mosfet would cause 5 in all to self destruct? I can get the ones I need for cheap enough, just wondering if it would be worth the time/money? Or would there be an underlying issue that would cause the FET to go up in smoke?
I know how to solder and use a multimeter. Learn really fast. A push in the right direction would be great. Thanks again.