Xerox 8850 Service Manual page 51

OF-1 Control Panel RAP
NOTE: Go to BSD 2.1 while using this RAP, unless otherwise directed.
This RAP is used when the Control Panel does not operate, or when the Control Panel oper-
ates incorrectly.
Initial Actions
• Make sure that AC power is applied to the machine.
• Check that the DC voltage LEDs are lit on the Main PWB (A3).
• Ensure that the 26-conductor ribbon cable, connected between the Main PWB A3J301
and the User Interface PWB A32J1 (located in the Control Panel), is seated fully at each
connector.
Procedure
Table 1 Control Panel Probable Cause / Corrective Action
Control Panel Probable Cause
The Message Display is There is an input power
blank, no characters are problem.
displayed.
There is an open circuit in
the ribbon cable between
the Main PWB A3J301 and
the User Interface PWB
A32J1.
There is an internal fault in
the Control Panel or in the
Main PWB A3.
The Message Display There is no +15 VDC to the
LEDs are on but no char- Main PWB, A3.
acters are displayed. There is no +5 VDC (Bulk) to
the Main PWB, A3.
The Message Display There is an open circuit in
LEDs are on but no char- the ribbon cable between
acters, random charac- the Main PWB A3J301 and
ters, or black squares the User Interface PWB
appear. A32J1.
There is an internal fault in
the Control Panel or in the
Main PWB A3.
8850/ 510DP
Corrective Action
Go to 1.1 AC Power RAP and 1.2
DC Power RAP.
Check for continuity in all wires in
the ribbon cable.
Replace the Control Panel, PL 1.4. If
the problem persists, replace the
Main PWB, A3, PL 1.1.
Go to BSD 1.2 to troubleshoot the
+15 VDC power to the Main PWB,
A3.
Go to BSD 1.2 to troubleshoot the
+5 VDC (Bulk) power to the Main
PWB, A3.
Check for continuity in all wires in
the ribbon cable.
Replace the Control Panel, PL 1.4. If
the problem persists, replace the
Main PWB, A3, PL 1.1.
03/2003
2-17
OF-2 Power On Self Test (POST) RAP
NOTE: Go to BSD 1.2 and BSD 2.1 while using this RAP.
This RAP is used when the logic detects a fault during the Power On Self-test (POST). The
printer does not initialize and the Control Panel displays a 1, 2, 3, 5, 6, or 7.
Initial Actions
• Ensure that the NVRAM are seated fully on the Main PWB, A3.
• Ensure that the 26-conductor ribbon cable, connected between the Main PWB A3J600
and the Control Panel User Interface PWB A32J1, is seated fully at each connector.
Procedure
Table 1 Power On Self Test (POST) Probable Cause / Corrective Action
The number that is Probable Cause
Displayed on the
Control Panel.
1 or 2 There is a fault in the RAM
memory.
3 The contents of the Control
EPROMs does not agree with
the checksum.
The Main PWB is defective.
5 There is a fault in the Main
PWB, A3.
6 There is a +5 VDC fault in the
Digital-to-Analog Converter .
7 There is a fault in the printer
port output circuitry.
OF-1 Control Panel RAP, OF-2 Power On Self Test
Corrective Action
Replace the Main PWB, A3, PL 1.1.
Replace both Control EPROMs on
the Main PWB, A3.
Replace the Main PWB, A3, PL 1.1.
Replace the Main PWB, A3, PL 1.1.
Replace the Driver PWB, A2, PL
1.1A.
If the problem persists, replace the
Main PWB, A3, PL 1.1.
Replace the Main PWB, A3, PL 1.1
Status Indicator RAPs