You have very good suggestions about checking capacitors. I did not know capacitors could cause the fan motor to intetmittenty run an stop. So The owner was desperate, I bought the expansive board, the fan is working now. Have to observe a few days. If it's still good, we will be laughing. This fan has been giving trouble for a few months. I will Chek the old board later. The symtom was it would run 15 seconds stop 1 second, run 15 seconds, stop for 1 second. Sometimes even the condenser fan stops half a second when the evaporator fan stops. Eventually the evaporator fan just permanently stop, but the condenser fan is still going. Sometimes, the evaporator fan would run for 2 seconds and stop for 1 second twice before running for 15 seconds.