Xerox 7750DXF - Phaser Color Laser Printer User Manual

Error Messages and Codes 3-17
Transfer Roller Contact Failure, Code 20
Transfer Roller Retract Failure, Code 21
The Transfer Roller did not meet the contact position, or the Transfer Roller did not
reach the retract position.
Troubleshooting References
Applicable Parts Wiring and Plug/Jack Map References
■ Left Door
■ Retract Home Sensor
■ Engine Control Board
Troubleshooting Procedure
Step Actions and Questions Yes No
1
1. Enter service diagnostics and run the
2nd BTR Motor test.
2. Does the motor operate correctly?
Go to step 2. Go to step 5.
2
1. Clean the 2nd BTR retract sensor.
2. Does the error still occur?
Go to step 3. Complete.
3
1. Use service diagnostics transmissive
sensor test.
2. Does the sensor operate correctly?
Go to step 4. Replace the
sensor or left
hand door
assembly.
4
1. Check the transfer roller transmission
gears for damage.
2. Are the gears damaged?
Replace the left
hand door
assembly.
Go to step 6.
5
1. Remove the left-hand rear mid cover.
2. Inspect the left-hand cover assembly
wiring harness for damage and ensure
the connectors are all properly seated.
3. Is the wiring harness damaged?
Replace the left-
hand cover
assembly.
Go to step 6.
6
1. Remove the rear cover and rear shield.
2. Reconnect power and enter service
diagnostics.
3. Measure the voltage at the engine
control board J533B9 while running the
2nd BTR Motor test several times.
4. Does the voltage toggle between
+5 VDC and 0 VDC when the test is
running?
Replace the
engine control
board.
Replace the
transfer roller
retract sensor.

Xerox 7750DXF - Phaser Color Laser Printer Specifications

General

Brand	Xerox
Model	7750DXF - Phaser Color Laser Printer
Category	Printer
Language	English