Mitsubishi PUHZ-P100VHA2-UK ACTM board keeps blowing!

[Elliot]

I have recently been having ongoing problems with this unit, recently fitted a new power board and noise filter board. Returned yesterday to fit ACTM board, switched on, compressor started to run so sat in van, when I came back found had tripped and ACTM board had blown again, I do however have a spare ACTM board on van. I've fitted it and wanted to find out if power board has gone too so I've powered it up and the 2 led's have lit so no other damage but I quickly powered it down just incase. The only thing I can think of is the compressor is faulty but don't want to try it or disconnect it incase the board blows again, any suggestions???! It's single phase.

[RusBuka]

ACTM board what is that?

[Elliot]

A small board approx 3 inches squared connects to power board

[RusBuka]

http://www.secure.dover.gov.uk/planning_online/acollate_docs/94061_12.pdf

[frank]

Hello Eliot

Reading your post regarding not want to disconnect the compressor to test it makes me think that you may not be qualified?

Surely, if you know how to check a compressor, you would have done it now and posted that the compressor is either 'OK' or is the cause of your PCB's blowing.

If you think the compressor is faulty, why don't you test it?

[RusBuka]

Its not PCB blowing, its just Active Noise Filter with reactor. I dont know words how to tell what wrong.
After ACTM power going to IPM.
I think topic starter dont tell us something interesting, what he dont understand.

[RusBuka]

Test compressor windings, it can be short circuit between windings. As the power module can be damaged because of an overheat. HeatSink pure?

[Elliot]

Hello Eliot

Reading your post regarding not want to disconnect the compressor to test it makes me think that you may not be qualified?

Surely, if you know how to check a compressor, you would have done it now and posted that the compressor is either 'OK' or is the cause of your PCB's blowing.

If you think the compressor is faulty, why don't you test it?

Frank are you taking the P*ss?! I've checked the windings of the compressor, 0.8 ohms across each winding actually.

[Elliot]

What I mean is I'm worried about switching unit on again and blowing a third ACTM board, but yea agree with rusbuka, could be heat sink problem, not dispersing the heat therefore blowing the board!

[Mick13]

heat transfer paste?
thats exactly what happens if heat paste is required and not fitted....
can only take a few minutes..

[RusBuka]

If the winding becomes isolated on itself, its resistance will change a little, and here the quantity of rounds will exchange. That will lower the capacity and power keys will be heated more strongly. It is possible to check it only measurement of inductance of each winding.

[install monkey]

have u meggered it??
Frank are you taking the P*ss?! I've checked the windings of the compressor, 0.8 ohms across each winding actually.

[monkey spanners]

have u meggered it??

Stop insulting the man! Jeez!

[install monkey]

valid question as the poster hasnt mentioned about testing the windings to earth :D
QUOTE=monkey spanners;276794]Stop insulting the man! Jeez![/QUOTE]

[frank]

The only thing I can think of is the compressor is faulty but don't want to try it or disconnect it in case the board blows again

Not what I would call an experienced method of testing

[frank]

I've checked the windings of the compressor, 0.8 ohms across each winding actually.

What is the reading to earth?