Xerox 7700DX - Phaser Color Laser Printer Service Manual page 83

Error Chain /
Code Link
20 09-342
Enter Service Diagnostics Mode.
Perform the "2nd BTR Motor" test. Listen for a short run of the motor.
Did the motor run?
Yes No
Remove the Left-Hand Rear Mid Cover (RRP 5, on page 7-158).
Inspect the Left-Hand Cover Assembly wiring harness for damage and ensure all
connectors are properly seated.
If the problem persists, replace the Engine Control Board (RRP 42, on page 7-206).
If the problem continues to persist, replace the entire Left-Hand Cover Assembly
(RRP 6, on page 7-160).
Remove the Rear Cover (RRP 1, on page 7-154) and Rear Shield (RRP 9, on page 7-163).
Reconnect power and enter Service Diagnostics Mode.
Measure the voltage at the Engine Control Interface Board P532A-14 (see figure page 2-46).
Perform the "2nd BTR Motor" several times.
Does the voltage toggle between +5 VDC and 0 VDC when the test is run?
Yes No
Replace the Transfer Roller Retract Sensor.
Replace the Engine Control Board (RRP 42, on page 7-206).
21 09-343
Enter Service Diagnostics Mode.
Perform the "2nd BTR Motor" test. Listen for a short run of the motor.
Did the motor run?
Yes No
Remove the Left-Hand Rear Mid Cover(RRP 5, on page 7-158).
Inspect the Left-Hand Cover Assembly wiring harness for damage and ensure all
connectors are properly seated.
If the problem persists, replace the Engine Control Board (RRP 42, on page 7-206).
If the problem continues to persist, replace the entire Left-Hand Cover Assembly
(RRP 6, on page 7-160).
Remove the Rear Cover (RRP 1, on page 7-154) and Rear Shield (RRP 9, on page 7-163).
Reconnect power and enter Service Diagnostics Mode.
Measure the voltage at the Engine Control Interface Board P532A-14 (see figure page 2-46).
Perform the "2nd BTR Motor" several times.
Does the voltage toggle between +5 VDC and 0 VDC when the test is run?
Yes No
Replace the Transfer Roller Retract Sensor.
Replace the Engine Control Board (RRP 42, on page 7-206).
ERROR 20 TRANSFER ROLLER CONTACT FAILURE
ERROR 21 TRANSFER ROLLER RETRACT FAILURE
Phaser 7700 Color Laser Printer Service Manual
Front Panel Message
2-53