Kyocera KM-2550, Service Manual

Page: 157 / 282

2FT
1-5-27
(1) No image appears (entirely white).
Causes
1. No transfer charging.
2. No LSU laser is output.
3. No developing bias is output.
Causes Check procedures/corrective measures
1. No transfer charging.
A. The connector terminals of the high-volt-
age PCB make poor contact.
Reinsert the connector. Also check for continuity within the connector
cable. If none, remedy or replace the cable.
B. Defective engine PCB.
Replace the engine PCB and check for correct operation.
C. Defective high-voltage PCB.
Replace the high voltage PCB and check for correct operation.
2. No LSU laser is output.
A. Defective laser scanner unit.
Replace the laser scanner unit (see page 1-6-29).
B. Defective main PCB.
Replace the main PCB and check for correct operation.
3. No developing bias is output.
A. The connector terminals of the high-volt-
age PCB make poor contact.
Reinsert the connector. Also check for continuity within the connector
cable. If none, remedy or replace the cable.
B. Defective engine PCB.
Replace the engine PCB and check for correct operation.
C. Defective high-voltage PCB.
Replace the high voltage PCB and check for correct operation.
(2) No image appears (entirely black).
Causes
1. No main charging.
2. Exposure lamp fails to light.
Causes Check procedures/corrective measures
1. No main charging.
A. Broken main charger wire.
Replace the main charger unit (see page 1-6-40).
B. Leaking main charger housing.
Clean the main charger wire, grid and shield.
C. The connector terminals of the high-volt-
age PCB make poor contact.
Reinsert the connector. Also check for continuity within the connector
cable. If none, remedy or replace the cable.
D. Defective engine PCB.
Check if YC9-5 on the engine PCB goes low when maintenance item
U100 is run. If not, replace the engine PCB.
E. Defective high-voltage PCB.
Check if main charging takes place when YC1-12 on the high-voltage
PCB goes low while maintenance item U100 is run. If not, replace the
high-voltage PCB.
2. Exposure lamp fails to light.
A. The connector terminals of the exposure
lamp make poor contact.
Reinsert the connector. Also check for continuity within the connector
cable. If none, remedy or replace the cable.
B. Defective inverter PCB.
Check if the exposure lamp lights when YC1-1 and 1-6 on the inverter
PCB go low while maintenance item U061 is run. If not, replace the
inverter PCB.
C. Defective engine PCB.
Check if YC17-1 and YC17-6 on the engine PCB goes low when mainte-
nance item U061 is run. If not, replace the engine PCB.