I emailed Panasonic, they said my air con is already 15 years old, they can't service it.
Anyway. I got another tech and solved the problem.
It's the capacitor not working and not activating the motor.
The idiotic part of this servicing experience is I asked two technicians and both i told them first that I suspect could be the capacitor spoilt. Because if the capacitor fail then the motor has difficulty kicking start ma tio bo.
One of them came never even see inside or test the electronics, I think he don't know how to test electrionic parts because he didn't bring any multimeter. Then said compressor must change say maybe circuit board or a switch inside spoilt. Never see inside and test anything and tell me maybe here and there, not very convincing to me. Later quote me a second hand unit which is just like 30% cheaper than a new one.
Circuit board i don't think so because if it stops working, it has a lower probability of being so intermittent unless connection got problem. The automatic switch maybe so i really tot was the problem.
Another tech online said straight must change a second hand compressor can't fix.
I get a third opinion. Tell them online specifically the problem and they said $40 bucks for inspection. I said okay.
Their guys came with a test meter, opened up the top of the compressor and diagnosed the readings. Changed the 25uf capacitor which was what I suspected in the first case and works again. Actually i see the internal, don't look hard to change but capacitor stores charges and can still leak electricity after removal so must leak the electricty from the part. Still don't suggest people to change themselves.
