
B–70115EN/03
10. REPLACEMENT PROCEDURES
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2. Remove the damaged diode by removing the screws and nuts
at the both ends.
In case of 9 kW power supply at first replace the cooling heat
sink and diode plate 1 and 2, then replace the diode block A and
B to remove diode.
CAUTION
When removing a diode, if it proves necessary to remove
the heat sink to which the diode is fixed, be careful not to
damage the insulating sheet under the heat sink.
3. Mount a new diode, then fix the diode using the screws and nuts.
In case of 9 kW power supply mount the diode block with
temporarilly fastening of replaced diode and fix after deciding
the direction of mounting diode.
CAUTION
Two types of diodes, UES806 and UES806R (alternative
model: UES805R) are used (see Fig. 10.2 (e), (f) and (j)).
When replacing a diode, it must be replaced with one of the
same type.
3) Checking for and replacing a damaged FET module PCB (See Fig.
10.2 (g) (i).)
1. To check whether an FET module PCB is damaged, measure the
resistance between check pins D and S or screws A and B (6 kW
power supply) shown in the figure. When the 9–kW power
supply is being used, measure the resistance at both of these
points for each of FET (1) and FET (2). These are separate
circuits. A resistance of less than 10 kW indicates that the FET
module PCB is damaged. (A normal FET module PCB will
have a resistance of about 30 kW to 10 MW.)
2. Remove the damaged FET module PCB as follows: Remove
the six screws shown in the figure (A, B, and C), disconnect the
green cables from connectors CN72 and CN73, then lift the
PCB upwards.
When the 9–kW power supply is being used, disconnect the
cables and remove the screws, then remove the step–up
transformer PCB, before removing the damaged FET PCB.
CAUTION
Do not disconnect the green cables from the lower PCB
(A20B–1006–0060).