JL Audio 400/4 amplifier not working. Please Help

kccapn

Member
2012-07-27 12:13 am
Texas
I'm working on a JL Audio 400/4 amplifier. I hooked it up to test it and the output goes on and off as the music is playing. It seems like the power supply in the amp is clipping on and off.

Any help would be greatly appreciated. I repaired my 500/5 with the help of Perry Babin and it's still working great. I'd like to get this one working as well.

Thank you
 
If the amp is not completely disassembled, lift the preamp board slightly and push it back down. Do this several times. If the amp is apart, do this but fully separate the boards. Make absolutely sure that all connectors are mated together properly BEFORE applying power again.

Does this help?
 

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kccapn

Member
2012-07-27 12:13 am
Texas
I removed and re-seated the board several times. It doesn't seem to going in and out now, although I can't fully test it yet due to my bench power supply not being big enough, (only 12.5 amps). I'm now getting the "Low Impedence" light on the amp. I'll test the amp under full power tomorrow when I get it to the car and supply enough current to the amp to fully test it.