Xerox Phaser 790, Service Manual

Page: 182 / 653

10/00
2-168
Phaser 790/DocuColor 2006
010-353/356/357
Initial Issue Status Indicator RAPs
010-353/356/357 Fuser Low/Under Temperature Condition
RAP
• 010-353 - A Fuser low temperature error has been declared. One of the following condi-
tions exist:
– an abnormally low fuser temperature has been detected by the Temperature Sensor.
– the Fuser On signal remains on too long - normal operating temperature cannot be
maintained.
• 010-356 - A Fuser Lamp error has been declared because both Fuser Lamps have been
turned on for more than 60 consecutive seconds in an effort to maintain a Ready Condi-
tion.
• 010-357 - The Temperature Sensor detected that the Fuser did not reach operating tem-
perature within a specified period of time. A Fuser Warm-Up Timeout error has been
declared.
Initial Actions
Inspect the Fuser area (especially around the Temperature Sensor) for any damage, foreign
material, debris or other signs of wear. Perform any necessary cleaning or maintenance in the
Fuser area. If the problem persists, continue with this RAP.
NOTE: Before beginning the Procedure below, remove the Inverter Upper Assembly REP 8.33
and the Fuser Tray Handle (PL 8.4).
Procedure
Switch on power to the copier/printer. A glow can be seen coming from the area of the Heat
Roll and Pressure Roll Heat Lamps when power is applied (viewed from the left side of
the copier/printer, just above the green Fuser Nip Handle).
Y
N
Remove the Rear Cover REP 14.6. Switch off power to the Copier/Printer and disconnect
the power cord. Continuity can be measured between J 34-1 and J34-2 on the Low
Voltage Power Supply (LVPS).
Y
N
Remove the Fuser Assembly REP 10.1. Continuity can be measured between P
79-1 and P79-2 on the Main Fuser Assembly.
Y
N
Remove the Upper Plate REP 10.4. Check for continuity directly across the
Pressure Roll Heat Lamp and the Heat Roll Heat Lamp. If continuity is NOT
measured, replace the Heat Lamps as required (PL 8.3). Also check for conti-
nuity directly across the Thermal Fuse and the Thermostat. If continuity is NOT
measured across either component, replace the Upper Plate (PL 8.2).
Go to Flag 1 and Flag 2. Check for an open circuit. The wiring is OK.
Y
N
Repair or replace the Fuser Connector Harness or the Main Harness (PL 11.1),
or the Fuser Harness (PL 8.5) as required.
Go to Flag 3 and Flag 4. Check for an open circuit. Repair or replace the Fuser Con-
nector Harness or the Main Harness (PL 11.1), or the Fuser Harness (PL 8.5) as
required.
Reconnect the power cord and switch on power to the Copier/Printer.
NOTE: Line Voltage = 110VAC for a 60 Hz System. Line Voltage = 220VAC for a 50 Hz
System.
Line Voltage is measured between J 34-1 and J34-2 on the LVPS.
Y
N
Access the Digital Output (DO) test from the Control Panel. Enter code [47]. Press
the Item/Enter button. The Display is 0.
Y
N
Check the wire between J 32-2 on the LVPS and J 21-3 on the MCU PWB for
an open circuit or a short circuit to ground. Repair or replace the Fuser Connec-
tor Harness or the Main Harness (PL 11.1) as required. If the wiring is OK,
replace the MCU PWB (PL 11.2).
Replace the Low Voltage Power Supply (PL 11.1).
The problem may be intermittent. Go to Figure 1. Check for loose or damaged connec-
tions or damaged wires. If the wiring is OK, go to 010-701 Faulty Temperature Sensor
RAP to troubleshoot the problem. If the problem persists, replace the Main Fuser or the
Fuser Tray (PL 8.1).
The problem may be intermittent. Go to 010-701 Faulty Temperature Sensor RAP to trouble-
shoot the problem. If the problem persists, replace the Main Fuser or the Fuser Tray (PL 8.1).
A
A