Carrier 42QHF012DS Service Manual page 61

Pic 1: check the voltage of N to S (Vs), is it moving
alternately between positive value and negative
value?
Pic 2:IPM or outdoor main PCB (For
38VNM218713)
Pic 3: IPM or outdoor main PCB (For
Power,
38VNM327713 / 38VNM436713)
Self-Check
Operating
PIC 4 :Main board LED when power on and unit
standby.
PIC 5: check point button,
Press 1 time for check how many indoor units are connected
61 / 78
Operating
Self-Check