Hitachi RAS-(3-6)HVRNM2E Service Manual page 315

8 Troubleshooting
2. Checking method of transistor module
• Outer appearance and internal circuit of transistor module
1. Drive circuit.
2. Overheating protection circuit.
3. Sensor.
• Procedure:
Remove all the terminals of the transistor module before check. If items (a) to (d) are performing and the results are
satisfactory, the transistor module is normal. Measure it under 1kΩ range of a tester. Do NOT use a digital tester.
a. By touching the + side of the tester to the P terminal of tran-
sistor module and the - side of tester to U, V and W of transistor
module, measure the resistance. If all the resistances are from 1
to 5kΩ, it is normal.
b. By touching the - side of the tester to the P terminal of transis-
tor module and the + side of tester to U, V and W of transistor
module, measure the resistance. If all the resistances are greater
than 100kΩ, it is normal.
c. By touching the - side of the tester to the N terminal of transis-
tor module and the + side of tester to U, V and W of transistor
module, measure the resistance. If all the resistances are from 1
to 5kΩ, it is normal.
d. By touching the + side of the tester to the N terminal of tran-
sistor module and the - side of tester to U, V and W of transistor
module, measure the resistance. If all the resistances are greater
than 100kΩ, it is normal.
305
SMGB0064 rev.0 - 08/2011
1
1
1
1
1
1
1
3
2
8