TROUBLESHOOTING Service Manual M4 - M10
11.07.2002 Page 60
If the IGBT seems to be as normal, reason for the malfunction is probably in
control circuitry and is leading to procedure to replace the Power board as
instructed in instructions 13.4.1.
Failed IGBT shall be replaced only with original spare parts, delivered by
Service network. Follow instructions 8.4.4 and 8.2.5 to make successful
replacement in the first time.
See brake feed back settings (S4, S5) of Extender board.
With software 52.00 or later there is fault indication F12 for brake chopper
fault (or missing brake resistor). Resistance values of brake resistors can be
founded from Brake Resistor Manual.
7.3.2.6 Checking of charging circuit
See the chapter 8.3 operation and troubleshooting of the main circuit.
7.3.2.7 Checking of rectifiers
See the chapter 8.2.3 for troubleshooting.
7.3.2.8 Checking of DC bus capacitors
To check DC bus capacitors external adjustable DC power supply is needed.
Functional checking:
Charge up DC capacitors one by one slowly up to nominal voltage of
component and check leaking current. Value of leakage current should not
exceed 2mA after voltage is stabilised up to present input voltage.
Warning:
Charged capacitors will maintain dangerous voltage for a long time and due
the safety they should be discharged by resistor of suitable voltage/power
capacity after test.
Replacement:
In case of faulty capacitor all the capacitors connected in series with the faulty
one has to be replaced. In 400 and 500V there are also parallel-connected
capacitors and in those cases also the parallel capacitors have to be replaced.
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