Hitachi RAS-2-HVNP Service Manual page 295

8. Troubleshooting
Transistor module checking procedure
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 [1] – [4] are performed and the results are satis-
factory, the transistor module is normal.
Measure it under 1kΩ range of a tester.
N O T E
DO NOT use a digital tester.
1 By touching the + side of the tester to the P terminal of transistor
module and the - side of tester to U, V and W of transistor mo-
dule, measure the resistance. If all the resistances are from 1 to
5kΩ, it is normal.
2 By touching the - side of the tester to the P terminal of transistor
module and the + side of tester to U, V and W of transistor mo-
dule, measure the resistance. If all the resistances are greater
than 100kΩ, it is normal.
3 By touching the - side of the tester to the N terminal of transistor
module and the + side of tester to U, V and W of transistor mo-
dule, measure the resistance. If all the resistances are from 1 to
5kΩ, it is normal.
4 By touching the + side of the tester to the N terminal of transistor
module and the - side of tester to U, V and W of transistor modu-
le, measure the resistance. If all the resistances are greater than
100kΩ, it is normal.
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