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12v Power Inverter for a Car

I have managed to stump everyone on my usual forum in hopes of finding someone to help me with the power inverter from my car.

I found another thread on when googeling my problem, I posted on that website but there hasent been any responses. I have the exact same hardware but a different failure. To my eye it seems very similar in design to a 12v car audio amplifier except it seems to be just generating a modified square wave all day instead of music.

http://www.diyaudio.com/forums/power-supplies/146342-about-repairing-1750-watt-power-inverter.html

Mine is the same hardware but I don’t seem to have any shorted transistors or diodes of the ones that are bolted to the heat sink. My hardware is identical to all of his pictures I just seem to have a different failure. I have the battery voltage appearing at the display and the red fault light on. schematics dont seem to exsist for this thing which is making it difficult to chase down the problem.

Symptoms,
I have no gate voltage to the IRF3205 but I have 15v drain
I have ground on the source and drain IRF640 and 15v on gate.

All the controller and timer ICs seem to be getting VCC power, I posted all of the pin outs from the ICs. If you see on the KA3525A I have 5v on the shutdown pin. I dont know what would have caused this or how to fix it. Any help would really be appreciated. I can post more voltage readings or more pictures if someone is willing to help me through this.

I have 3 of these power inverters I keep buying and blowing up they all have the same symptoms with no burnt internal components and just the red fault light on. I would really like to know how to service these things because I need them for work and they are expensive. I am shocked to see how similar they are to car audio amplifiers. I have most all of the outputs and power supply FETs left over from other amp repairs I have done. so most of the parts I have already laying around.


1.) CDE4013BE SMPS Controller
2.) KA3525A
3.) LM339N Comparator
4.) LM358N
5.) NE556N Timer
 

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Here are some more pictures
 

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