MOD NOTE: Split from: https://forum.allaboutcircuits.com/threads/dc-refrigeration-compressor.193268/

My Danfoss 102N3030 compressor controller reads short to ground on each of the 4 leads heading to my compressor.

is this an indication of shorted Mofsets? If so which ones are the mofsets in this picture?

Thanks for the advise. I’m a ship design engineer and all these electrons leave me struggling.

 

It is hard to see much from the board, but to me, the top of the large electrolytic capacitor looks to be bulging up a bit. That is a sign of a failed cap and if that is so, it could have caused quite a lot of other damage.
And the compressor motor may be run via TRIACs, not FETS.
When you say "short to ground", is that 0 ohms or just a low resistance? Was that to the chassis ground or the common voltage rail of the PCB?
And did you measure it with the compressor connected?
Is there a circuit printed on the case of the machine?

 

Resistance check of a compressor is done with it disconnected from the driver module. Always. Just like "DD" tells.

 

MOSFETs often short to ground.
MOSFETs are cheap.
Digikey is a good source.
If you can read the part number, changing them is worth a try.