8  Troubleshooting
305
SMGB0064 rev.0 - 08/2011
8
2. Checking method of transistor module
•  Outer appearance and internal circuit of transistor module
1. Drive circuit.
2. Overheating protection circuit.
3. Sensor.
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•  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.