Konica Minolta 0902, Service Manual

Page: 89 / 302

Chapter 3 Troubleshooting
3-35
Analysis Procedure of Power Supply Problems (Cannot Turn ON the
Power Supply)
When the power does not go ON by pressing the "operation" switch, confirm from top of the next table,
and respond accordingly. (See next page for the position of each parts.)
*: Only circuit board and power supply is described for faulty parts. Confirm the wiring too.
No. Confirm Possible fault location
for no output *
1 Connect the power cable to the outlet, and confirm that there
are specified voltage on the plug on other side. Power cable
2 Confirm that second front door is closed. Close the second front door.
3 Confirm that the position of the interlock switch (SW1) is
adjusted. Adjust the position.
4 If above is normal, confirm that the resistance between the
contacts is open on the interlock switch (SW1) when the
second front door is closed.
Measuring point: JJ10-1 pin ~ 2 pin
Interlock switch (SW1)
5 Confirm that the resistance between the contacts is open on
the "operation" switch while the "operation" switch is pressed.
Measuring point: MCN2-1 pin ~ 10 pin
OPB
6 Confirm that AC 110 - 120 V is output on the secondary
connector of the transformer (JJ2 and JJ3) after turning ON
the power supply circuit breaker.
Measuring point: JJ2-1 pin ~ 2 pin
JJ3-1 pin ~ 2 pin
•
AC inlet
•
Power supply circuit breaker
(SW2)
•
Noise filter (NF1)
•
Transformer (PT1)
•
Wrong tap connected to the
transformer
7 Confirm that standby power supply is supplied to the MDU
power supply connector after turning ON the power supply
circuit breaker.
Measuring point: MCN7 - 1 pin = 5 V ~ 2 pin = 0 V
Standby Power supply (SUP2)
8 Confirm the power supply control output from the MDU while
pressing the "operation" switch after turning ON the power
supply circuit breaker.
Measuring point: CN3 -1 pin
≒
0 V
MDU if it is 5 V
9 Confirm the output from the PCU while pressing the
"operation" switch after turning ON the power supply circuit
breaker.
Measuring point: PCN2 - 1 pin ~ 5 pin = AC 110 - 120 V
PCU
10 Confirm the that there is normal output from the SUP1 (JP25)
while pressing the "operation" switch after turning ON the
power supply circuit breaker.
Measuring point: JP25-
3 pin = 24 V ~ 2 pin = 0 V
4 pin = 24 V ~ 2 pin = 0 V
7 pin = 5 V ~ 6 pin = 0 V
8 pin = 5 V ~ 6 pin = 0 V
Digital power supply (SUP1)
11 When all above are normal
•
MDU
•
CIU