S0740 800 179/E071123/P64
-- 4 8 --
ct33f3acpwr
Checking the IGBT modules of AC power board 18AP2
Disconnect the machine from the mains and follow the instructions below. The numbers of
the instructions refer to the diagrams on this and next page.
Before measuring: disconnect connector 18XS3 from terminal CN1 and the positive and
negative voltage supply bars from the circuit board.
1. Use a multimeter in diode test position. Measure with the positive and negative of the
multimeter connected as shown in the pictures. The forward voltage drop of the diode
must be 0.3 to 0.5 V.
2. Measure the resistance between collector and gate of the transistors, it must be higher
than 100 kohm. The measured resistance is partly depending on the meter that is used,
it may be in the range from 100 kohm to 4 Mohm. A faulty transistor is in most cases
short--circuited between collector and gate.
3. Measure the resistance between emitter and gate of the transistors, it must be about
100 kohm. The measured resistance is the resistance of the gate resistor. A faulty
transistor may have a short--circuit between emitter and gate.
Circuit diagram AC power board 18AP2, measuring points IGBT modules
4. To check the NTC resistors:
a. Measure between pin 19 and 20 on each one of the modules.
b. The resistance must be 4 to 6 kohm at 20 _C.
To Next Page
Loading...
Need help?
General
