FUJI/FUJITSU 9K Split Outdoor unit problem

[selectaircon]

I've been asked to look at a FUJI 9K Inverter ROR09LCC. I'm presuming FUJI's are linked to Fujitsu. Going off the indicator flashes, its highlighting a Voltage Trip.

After switching power off and on, Outdoor unit starts the fan for 1 second and then stops, Compressor doesn't try to kick in.

There is a click, I'm presuming from a relay on the PCB when the fan switches off.

As luck would have it, my clients had the same unit next to it and so I switched boards and it seemed to work ok for at least 30mins.

Put everything back together including the indoor unit that I'd pulled apart. Went to check it was still running........ No, original fault back.

Swapped the board back and its causing the same fault on the one that was originally working and so I have two units not working at the moment.

Any one with any suggestions

Mark

[momo]

Checked input voltages? Droop on power lines when caps charge or inverter pulls power ? (Faulty NTC resistor on charging circuit ?) Bad connection somewhere on supply? Mains surge recently? Edit: clarification

[Yuri B.]

Probably defective fan, defective control of it on the original PCB, now the other PCB is also spoiled.

[sweimaker]

check power supply to unit. if its single phase if 3 phase all phases

it sounds to me like the invertors dumping a voltage somewhere.. either fan motor or compressor, but sounds like invertor damage also. (usually comes in 2).

disconnect compressor.. try and run unit.. any different reaction? if same issue.

amp clamp on fan motor (look for high winding may say on electric cover) check if any silly amps.

also you could check ohms test between each winding..

hope it helps. :)