Blown Dual MOSFET ICs on inverter, what might be the cause?

[Dang]

I believe these are of the dual type, both an N and P working in parallel; there are two fuses, one to protect the bottom, one for the top, there's two banks of four MOSFETS ics for the bottom and two banks of three for the top, the second bank from the top have all blown and show definite signs of over heating on the back of the board and in turn taking out the top fuse, all measure shorted across source/gate pins, all I really want to know is why this may of happened, I fear a bad CCFL but I'm not really sure how to test for that, if you can help then I'm all ears, once again thank you, Andy.

[tom66]

Re: Blown Dual MOSFET ICs on inverter, what might be the cause?

If one FET failed drain-gate then it could have damaged all the others or caused them to all short the 24V through them, though I would more expect that to cause fuse to blow. Could also be bad controller IC or bad transformer. Bad bulb would be surprising.

[Dang]

Re: Blown Dual MOSFET ICs on inverter, what might be the cause?

If one FET failed drain-gate then it could have damaged all the others or caused them to all short the 24V through them, though I would more expect that to cause fuse to blow. Could also be bad controller IC or bad transformer. Bad bulb would be surprising.

Looking at the CN101 diagram on the inverter, it has five feeds of 24v with five returns to ground, from the power supply I've measured all these and I get 23v stable so I believe the power supply to be fully working, indeed there is a return/control feed for the inverter from the main board(fully on green light) with four feeds, from what I remember they are, ERROR OUT 0.8v, ENA, DIM, EX-DIM, I can't quite remember the other voltages but they are somewhere between 5v and 12v, I would say perfectly normal as the Tv still turns on and produces a picture with sound.

One new inverter coming up, it can be had for under a tenner so happy days, once again Tom66 and everyone else who helps me, thanks and as always it's very much appreciated, always learning, Andy.

[Dang]

Re: Blown Dual MOSFET ICs on inverter, what might be the cause?

So a new inverter cured it, all good.