Xerox 8850 Service Manual page 46

• Clean the Pressure Equalizing Tubes with a vacuum cleaner in order to remove toner
from inside the tubes. Clean the Augers and Magnetic Roll
• Ensure that the printer is level.
• Check that the mylar Toner Strip PL 9.7, Item 13 for damage.
• Run [09-21-4] to distribute the developer material.
Procedure
With the printer in an LL-90 fault condition, enter diagnostic code [9-22] and then press NEXT,
in order to enable the printer to function with an LL-90 fault condition. Enter the code [0361] in
order to exit the diagnostics mode. Re-enter Diagnostics and run 3 test prints [9-55 Pattern 5].
The LL-90 code is displayed as the print is being made.
Y N
Complete the service call.
Use the last print to check the image density. The image density of the 1.0 Solid Square in
the center of the Test Pattern [0955-5] is equal to or less than the 1.40 Density Square on
the Output Reference SIR 495.1.
Y N
Perform the Tone-Down Procedure
tone-down, replace the Developer Material
Enter the code [9-21-4] in order to switch on the Main Drive Motor and the Toner Control Ana-
log Signal. Connect the (+) meter lead to the Toner Sensor A22Q1P1-2 and the (-) meter lead
to A22Q1P1-4. There is +15 VDC present.
Y N
Check for an open or short circuit to ground in the wires connected to A22Q1P 1-2 and
A3P 606-15. If the wires are ok, replace the Main PWB, A3, PL 1.1.
Connect the (+) meter lead to the Main PWB A3606-4 and the (-) meter lead to ground. There
is +5.2 to +6.0 VDC is present.
Y N
Connect the (+) meter lead to the Toner Sensor A22Q1-1 and the (-) meter lead to
ground. There is greater than +0.2 VDC present.
Y N
Disconnect Toner Sensor A22Q1P1 from A22Q1J1. Connect the (+) meter lead to
the Main PWB A3J303-16 and the (-) meter lead to ground. There is greater than
+0.2 VDC present.
Y N
Replace the LVPS, A5, PL 1.1. If the problem persists, replace the Main PWB,
A3,
Check for an open or short circuit to ground in the wires connected to A22Q1-2 and
A22Q1-4. If the wires are OK, replace the Toner Sensor A22Q1, PL 9.9. Run [9-21-
6] Toner Sensor Calibration.
Check for an open or short circuit to ground in the wire connected to A22Q1P1-3. If the
wire is OK, replace the Toner Sensor A22Q1,
tion.
Replace the Main PWB, A3, PL 1.1.
Status Indicator RAPs
LL-90 Overtoned Fault RAP
GP 9 Tone Down Procedure. If the printer does not
[REP 9.7].
PL 9.9. Run [9-21-6 Toner Sensor Calibra-
03/2003
2-12 8850/ 510DP