You might even ask them if they have replacement mosfets for sale (for replacement and service) should they not want to tell you. If all else fails, goto your nearest tv repair shop, give him $20 for the time, let them order them for you, shops have more pull then an individual.

Those 12V 'ionizer' air cleaners will cook the inverter if they are on the same battery.

I fried the mosfets of a xantrex inverter about 6 months ago when I disconnected the batteries, kept the solar panels connected, and then plugged a power cord into the receptacle of the inverter. There was nothing at the other end of the cord. The Xantrex service people asked me if the inverter input voltage had gone high. At the time I said no, but on reflection, I guess it probably did go up to about 18 volts or so. I don't know if that's enough to damage the inverter, but I have been very careful not to expose my new inverter to high voltage, mainly by never disconnecting the batteries without first disconnecting the solar panels. So far, it has worked flawlessly (knock wood!)

I'm not familiar with Trace inverters but I presume this will be similar to other MSW inverters and your pics are of the H bridge output stage? That's a hell of a lot of mosfets for 1000Watts output so they must be quite low current rating. Looks as though there are 6 in parallel for each leg of the bridge. It shouldn't be too difficult to find a suitable replacement by looking through data sheets.

As has been suggested though, the drive circuitry may also be damaged so it will be no good just changing the output mosfets without checking the rest of the circuit. If you can trace back (no pun intended!) the gate connections from the mosfets they will be driven through a low value resistor from a driver transistor and these often go short circuit in circumstances like this.

Also it is quite probable that some or all of the mosfets in the DC to DC converter stage will have also blown.

I find the easiest way to tackle a repair like this is to remove all the mosfets and test them off the board (a simple test has been discussed on this board). Before replacing any of them I power up the DC to DC board and check the drive pulses to the mosfets with a scope. I also test the rectifier diodes that convert the AC output from the DC to DC stage to the high voltage DC as these sometimes blow. I then replace the DC to DC mosfets and check the DC on the smoothing caps. NOTE this is several hundred volts and not to be messed with!! You need to discharge the caps with a suitable resistor after testing to remove the dangerous voltages before going any further.

I then check the drive pulses to the H bridge mosfets to make sure they are OK.Then I just replace 4 of the output mosfets (one in each leg of the bridge) and check the final AC output. This ensures that if there is still a problem you will only blow 4 of your new mosfets instead of all of them! If this is ok I replace the rest of them. Hopefully that's the job done.

Altogether not a job for the faint hearted!

HOWEVER, I WOULD NOT RECOMMEND DOING THIS UNLESS YOU ARE CONFIDENT YOU KNOW WHAT YOU ARE DOING. You are dealing with potentially LETHAL voltages in an inverter and if careless you may not get a second chance.

Good luck!

Opposite side has Triac can on base and Caps.

Thanks for the extra info. However, I agree with TomW's comments. As I said before, if you are not confident, don't try repairing it yourself, find a repair man who can do it for you. Better safe than sorry.

Some ideas now for either you or your repairman:

The mosfets are switching the 12 volts DC to the transformer so this makes it a bit easier and safer to work on. They will be low voltage but high current rating. Something with a Vdss of say 55 volts and a current rating of at least 50 Amps for reliability. The mosfets are N channel and the package looks like D2PAK. STmicroelectronics do a wide range which would be suitable e.g STB80NF55 or STB150NF55. These should be more than adequate for the job. I would suggest ringing their technical department and explain the problem.

If you can find out what the original part is, all the better. However, in either case I would recommend replacing ALL of the mosfets. Even those that appear OK may have been stressed and could fail at a later date.

If you decide to have a go yourself then you will have to thoroughly check the rest of the circuit in case there are other failed components. Power the board up without the mosfets and check the drive pulses to the mosfet gates as mentioned before. Put a low amperage fuse in the battery supply just in case and if possible use a small battery for testing, not your main battery bank!

With regard to the cause of failure in the first place, it could be due to your use of the desulphator. These do put out very high voltage spikes which could exceed the working voltage of the mosfets.

Hope this helps, but take care!

Accidental battery (+) to invertor (-) will blow EVERY output transistor.