Then I read the net and found the relay box is the commonest fault. Then I go back and check
1) Voltage at the relay side : 3 pins -common, Run and start. The start/common pin reads erratic 180V-200V only , when the fridge is switched on. This makes me suspicious.
2) Check resistance of the 3 pins on the compressor and looks for 2 coils Ohm reading. The sum of the smallest 2 reading should equal the highest value. Make sure the pins are not ground as well. My readings are 10 Ohm, 6 Ohm and 16 Ohm. So I suppose that the coil is not dead.
The relay is then suspected to be faulty. On opening up the relay box, I found chips of broken ceramic disc (later I found this is the so called PTC relay, or labelled as PTC thermistor from the fridge offical circuit label. This ceramic disc is shattered that the 2 pins (run and start ) lost their connection at the spring contact. The largest piece of the ceramic is realigned such that the 2 pin contact on both sides of the disc. Contacts are sanded and sprayed.
Then I pray and switch the fridge again. Wow.. the compressor works again !
The above is the compressor relay, which is usually found on the side of the compressor with 3 pin socket. The ceramic disc is found shattered. This PTC thermistor works by channeling current to the "starter" coil in first second. Temperature/resistance increases and current goes through the "run" coil circuit then.
Largest remnant is placed over the contact pins as a temporary measure, till I found a replacement part.