Okay this what happened my buddy and I were clearing out his shed and he found a few old amps so we decided to try out the kicker zr amp and I connected it to my car it turned on nice the red power LED turned on and five minutes idling I didn't connect it to my stereo yet and I looked back and saw smoke coming out and freaked out on what I saw. Does anyone know what may have cause the amp to blow up for no reason? I know there are quite a few knowledgeable folks on here. Oh yeah my voltage to my cars charging system was at 12.6v with out the car running. I even checked all wiring and polarity it was all wired up correctly.
Yeah the supply mosfets blew open. It looks pretty bad too. And yes I did find a bunch of spider webs inside and dust. As there was no module for it either.
Yes that's what I used to clean it with my buddy of mine said to keep the amp since it's no good. Seems pretty "hefty". What's a good sub for the power MOSFET? Maybe I can get it to work?
Power MOSFETS are fairly easy to substitute in car amps....you need a breakdown voltage of at least 35V (to handle the peaks from the transformer), the lowest Rd-s ON you can find and the proper current rating. Of course it also needs to be the proper package and type. (most are N channel)
The switching frequency is not high enough to worry too much about speed these days. Just about any modern switching MOSFET will work in that regard.
The switching frequency is not high enough to worry too much about speed these days. Just about any modern switching MOSFET will work in that regard.
J
Okay the original had a rating of 50v and 75amps and yes this a N channel MOSFET but which is another good equvilant for this amp? Also it's a TO-247 pakage type.
Be careful with that sub....its current capability is lower than the original device. What *really* matters is current at temp...consult the current vs temp derating curves to determine if its a proper replacement.
I bet it would work....if the Kicker *really* needs those 5 extra amps, its a crap design for running its switchers too close to the absolute maximum ratings. (and it being a Kicker and an old school one at that...I bet its well designed.)
I doubt that this amp would qualify as a cr@p design. 4 of the 048s will work fine. I'm sure that there are thousands of these amps working to this day with the originals. The others may work but will be more difficult to drive and may require modification of the drive circuit.
This amp is unlikely to draw more than ~50 amps at full power.
It's also a regulated power supply so problems with insufficient drive current (especially when turning the FET off) could result in cross-conduction and could cause the supply to fail. The problem may not be evident unless/until the pulse width is driven to the maximum. Unless properly tested, the supply may fail when the amp is driven hard. To test for this at idle, the DC supply voltage would have to be reduced to force the supply to the maximum pulse width. If the idle current doesn't increase when the pulse width is at the maximum possible, the drive circuit is OK.
As long as he's willing to test the amp thoroughly, he should use something close the the original FETs. That's my opinion, anyway.
Chipper:
Have you tested the outputs to determine if any have failed?
If you decide to repair the amp, you need to clamp all FETs to the sink and insert a 10 amp fuse in the B+ line before applying power. If the fuse blows, you'll need to do a bit of troubleshooting. If there are no blown outputs and the bias pots haven't been tampered with but the amp is drawing excessive current, you may have a shorted power transformer or inductor. That may require that you use a current limiter to allow you to continue troubleshooting.
This amp is unlikely to draw more than ~50 amps at full power.
It's also a regulated power supply so problems with insufficient drive current (especially when turning the FET off) could result in cross-conduction and could cause the supply to fail. The problem may not be evident unless/until the pulse width is driven to the maximum. Unless properly tested, the supply may fail when the amp is driven hard. To test for this at idle, the DC supply voltage would have to be reduced to force the supply to the maximum pulse width. If the idle current doesn't increase when the pulse width is at the maximum possible, the drive circuit is OK.
As long as he's willing to test the amp thoroughly, he should use something close the the original FETs. That's my opinion, anyway.
Chipper:
Have you tested the outputs to determine if any have failed?
If you decide to repair the amp, you need to clamp all FETs to the sink and insert a 10 amp fuse in the B+ line before applying power. If the fuse blows, you'll need to do a bit of troubleshooting. If there are no blown outputs and the bias pots haven't been tampered with but the amp is drawing excessive current, you may have a shorted power transformer or inductor. That may require that you use a current limiter to allow you to continue troubleshooting.
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