Mitsubishi MUZ-GA60VA Power board fault

[dairytech]

Hi guys, I have an outdoor unit power board with a dead short on the input which obviously blows the fuse on the noise filter board.

Is there anything to look out for before replacing the board ... I've checked the compressor windings which appear ok

Does anyone have any idea what sort of price to expect ... I'm on holidays interstate in Australia and have had the run around online and by phone trying to get a starting point.

Actually need 2 of them ... 2 units on the same house are cactus !!!

Part numbers for the board I found from a manual I downloaded could be

E12 B79 440
E12 935 440
E02 935 440

The serial number of the units are ... 6000076 and 6002110

Thanks for any help.

[marc5180]

First thing to check would be the Neutral.

Make sure it isn't being switched through the mains power isolator.

[dairytech]

Hi Marc, thanks.

Both units failed several months apart at about 4.5 years of age ... and definitely not any wiring changes to the house.

I did find a gecko skeleton behind the filter board on one unit ... but it was right on the mains input terminal ... and I wouldn't have thought that would have caused problems upstream.

[dairytech]

First thing to check would be the Neutral.

Make sure it isn't being switched through the mains power isolator.

Sorry, I just reread your post ...

So are you saying that if the neutral is switched as well as the active ... it can cause problems ...

Or that if the neutral is being switched instead of the active?

[marc5180]

Sorry, I just reread your post ...

So are you saying that if the neutral is switched as well as the active ... it can cause problems ...

Or that if the neutral is being switched instead of the active?

Yes if the neutral is being switched as well as the mains incoming through the isolator.
Only last week I heard the same had happened on one of our sites to quite a few mitsi split units and this was due to the sparkles who had installed the power and they were switching the neutral.

[dairytech]

Yes if the neutral is being switched as well as the mains incoming through the isolator.
Only last week I heard the same had happened on one of our sites to quite a few mitsi split units and this was due to the sparkles who had installed the power and they were switching the neutral.

Mmmm .... ok.

I'm not sure what to think. I'm back down south now ... so I'll pass the details onto my friend and make sure he checks.

But again, they'd been working fine for nearly 5 years ... and he assures me no changes have been made to the wiring since installation.

In the meantime I discovered the faulty component on the power board ... it's a large IC module but is available from Hong Kong for less than $20 AUD including freight.

And I'll check tomorrow for the new board price.