Power circuit board, possible lightning surge question

[woody3882]

I have a Mr. Slim Mitsibushi split system mzx3B30na I believe a lightning storm created a power surge and possibly fried the board. How do I test the board to be sure it is bad before I pull it and replace. Indoor fans run then shut down after about six minutes. nothing outside runs. I am certified, have all the tools, and have worked on r-11, 12, 502, 22, 410a systems numerous times over the years, I am now retired, but this new DC inverter system is all new. I would be greatful to anyone that could help me out or connect me with some one that can.
Thanks

[FreezerGeezer]

Here's an extremely useful thread:
http://www.refrigeration-engineer.com/forums/showthread.php?37273-Inverter-Testing&highlight=Wendy%27s+inverter+testing

Thanks Tayters. :)

[passandscore]

Here's the manual
http://ecomfort.com/PDF_files/Mitsubishi/multi_zone/mitsubishi_mxz3b30na_service_manual.pdf

It may prove to be useful.

[FreezerGeezer]

Been working on a Mitsi Electric MXZ-4A80VA-A2 today. Gecko'd across the IPM, and no power out of the Noise Filter Board

I don't know if it's relevant to your unit, but the local tech support chap suggested the following:
Obtain a 2A (if you can, likely you'll only find 3A) breaker. Bypass the noise filter board, using the breaker & some wire. I.e, wire the input to the Reactor directly to the 240V incomer to the unit with the breaker in line. If it trips when you apply power, there's problems downstream of the noise filter board. If everything runs, the prime suspect is the relay on the noise filter board that sends power to the Reactor. (obviously in my case, there are problems downstream of the Noise Filter Board, but now I can say the Noise Filter is stuffed too.)
Comp. windings must all be the same, and read between .86-1.06Ohms.
Cond. fan cables must read between 13-16.5Ohms between each pair.
Reversing valve should read 1.5KOhms
Linear expansion valves:
The following should all read between 37-54Ohms:
W-R
R-O
Y-Br
Br-Bl

If any of those are off, repace that component as wel as the fried boards.

No responsibility is taken if I've misunderstood the tech. support bloke or otherwise made a mistake in the above. I'm a neophyte on splits, coming from a Chiller & commercial refrigeration background. Nonetheless I hope that it helps. :)

[cemsolak]

@woody3882's, finding out a fried circuit board is generally easy, all you need to do is a few continuity tests and you can see which connections are broken and which are shorted. However, in your case, I don't think the board is fried because if it were fried, it won't be working at all. Since it works till 6mins, that means there are one or two components which have gotten partially damaged and they either get heated up. You can start checking the relays first, replace any one with a working relay and see if there's any issue. You can also check the capacitors, there might be a blown capacitor which is either completely open or completely shorted. For the second phase of the circuit which deals with the exterior appliances, check its power IC, capacitors and tracks in general because it will most probably be blown up. Also, do check the fuses. Hope this helps.