IVT 12KHR-N Service Manual page 34

12KHR-N
2. Troubleshooting of outdoor unit electric components
Check 220-240VAC
input voltage.
NO
Does LED light?
YES
NO
Does LED flash?
YES
Normal
NO
Check 320VDC
between IPM pins
(20) and (24) ?
YES
NO
Check switching
power supply
output of 12 VDC,
15 VDC ?
YES
NO
Check 5 VDC
output ?
YES
3 – 12
Short-circuit in DC fan motor
Short-circuit in IPM
Short-circuit in diode bridge
Blown fuse
Defective electrolytic capacitor
Wire disconnection, PWB pattern damage
Short-circuit in PAM IGBT (Q5)
Defective switching power supply circuit
Malfunction of 3-terminal regulator IC4, IC1
Short-circuit in expansion valve coil
Malfunction of transistor array IC7
Solder contact or other problems
Malfunction of 3-terminal regulator IC4, IC1
Microcomputer oscillator error
Malfunction of microcomputer reset IC
Malfunction of microcomputer
Malfunction of serial signal circuit
Check wiring between indoor and outdoor units.