3MX
1-4-5
1-4-3 Electric problems
Troubleshooting to each failure must be in the order of the numbered symptoms.
Problem
Causes
Check procedures/corrective measures
(1)
The original feed
motor, original con-
veying motor or origi-
nal switchback motor
does not operate.
1. Poor contact in the con-
nector terminals.
Reinsert the connector. Also check for continuity within the con-
nector cable. If none, remedy or replace the cable.
2. Defective drive transmis-
sion system.
Check if the rollers and gears rotate smoothly. If not, grease the
bushings and gears. Check for broken gears and replace if any.
3. Defective motor.
Run maintenance item U243 and check if the motor operates. If
not, replace the motor.
4. Defective DP main PWB. Run maintenance item U243 and check if the motor operates. If
not, replace the DP main PWB.
(2)
The DP cooling fan
motor does not oper-
ate.
1. Poor contact in the con-
nector terminals.
Reinsert the connector. Also check for continuity within the con-
nector cable. If none, remedy or replace the cable.
2. Broken motor coil.
Check for continuity across the coil. If none, replace the motor.
(3)
The switchback feed-
shift solenoid or
switchback pressure
solenoid does not
operate.
1. Defective solenoid coil.
Check for continuity across the coil. If none, replace the solenoid.
2. Poor contact in the con-
nector terminals.
Reinsert the connector. Also check for continuity within the con-
nector cable. If none, remedy or replace the cable.
3. Defective DP main PWB. Run maintenance item U243 and check if the solenoid operates. If
not, replace the DP main PWB.
(4)
A message indicating
cover open is dis-
played when the doc-
ument processor top
cover is closed cor-
rectly.
1. Poor contact in the con-
nector terminals of DP
interlock switch.
Reinsert the connector. Also check for continuity within the con-
nector cable. If none, remedy or replace the cable.
2. Defective DP interlock
switch.
Check for continuity across the contacts of the switch. If none
when the switch is on, replace DP interlock switch.
(5)
An original jams
when the main power
switch is turned on.
1. A piece of paper torn
from an original is caught
around the switch.
Remove any found.
2. Defective DP timing
switch or original switch-
back switch.
Run maintenance item U244 and turn the switch on and off manu-
ally. Replace the switch if indication of the corresponding switch is
not light.
Summary of Contents for DF-420
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