SERVICE CALL CONDITIONS
SM
4-109
B234/B235/B236/D101/D102/D103
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4.2.5
PSU PROTECTION CIRCUITS
Overview
The diagram above shows the outputs of each converter listed in Table 1.
PSU-C and PSU-E comprise the PSU. PSU-E consists of two PCBs: PCB A and
PCB B. There is a total of five converters:
•
PSU-C contains the energy save converter.
•
PCB A of PSU-E contains the 1st and 2nd converter.
•
PCB B of PSU-E contains the 3rd and 4th converter.
The PSU contains several protective circuits that will cut power to prevent damage
to the machine and dangerous fire hazards that could be caused by harness short
circuits or damage to the PSU circuits due an accidental power overload. These
protective circuits are provided at three locations:
•
AC input
•
Converter control points
•
Output points
Even if one or more of these protective circuits should fail, the others will act as
backup to cut power to the machine if a problem occurs,
The output points are provided with electronic interrupt circuits, so fuses are not
required at these locations.
PSU-C
Converter
(5.1V 12V)
Control System
Electronic Interrupt
LED 5V
1st Converter
5.1V
LED 24V
2nd Converter
24V
LED 24VINT
3rd Converter
24V
LED 38V
4th Converter
38V
Control System
Electronic Interrupt
Control System
Electronic Interrupt
Control System
Electronic Interrupt
Control System
Electronic Interrupt
PSU-E
PCB A
PCB B
5.1 VE
12 VE
5.1 VL
5.1 V
24 V
24 V
38 V
FU1
FU3
FU001
FU002
FU101
Breaker SW
Main Power SW
Low
Power
Relay
Energy
Save
Relay
B234T901.W MF
