IVT AY-XP12JHR-N Service Manual page 33

AYXP12JHRN
No Item
.
3 IPM circuit check
4 Compressor check
5 Expansion valve check
6 Final check
2. Troubleshooting of outdoor unit electric components
Check 220-240VAC
input voltage.
NO
Does LED light?
YES
NO
Does LED flash?
YES
Normal
Check method
Check that 3 lamps (load) light.
Check position detection voltage (+15
V, 5 V) on control PWB.
Measure compressor coil resistance
(for each phase of U, V and W).
Use multi-meter or digital tester capa-
ble of displaying two digits right of the
decimal point (0.01Ω).
Measure expansion valve coil resis-
tance.
Turn off power, and connect compres-
sor cords to compressor.
Operate air conditioner.
Measure DC voltage between IPM
pins (20) and (24).
Check 320VDC
between IPM pins
(20) and (24) ?
Check switching
power supply
output of 12 VDC,
15 VDC ?
Check 5 VDC
output ?
Normal value/condition
Each voltage should be normal.
All 3 lamps (load) should light with
same intensity.
Resistance value at 20°C --- 0.65Ω
Each phase 46±3Ω (at 20°C)
Compressor should operate nor-
mally.
320 VDC or higher.
NO
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
YES
Short-circuit in PAM IGBT (Q5)
NO
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
YES
NO
Malfunction of 3-terminal regulator IC4, IC1
YES
Microcomputer oscillator error
Malfunction of microcomputer reset IC
Malfunction of microcomputer
Malfunction of serial signal circuit
Check wiring between indoor and outdoor units.
3 – 11
Remedy
Replace control PWB.
Correct connections at compres-
sor terminals.
Replace compressor.
Replace expansion valve.
Replace control PWB.
Replace outdoor unit thermistor.
Replace compressor (in case of
compressor lock).