Electrical Troubleshooting - Xerox Phaser 8860 Service Manual

Electrical Troubleshooting

The Electronics Module contains the power supply, main board containing the image proces-
sor, power control board, and in the case of the 8860MFP, the FAX circuitry. Also on the
8860MFP, the Backframe contains the Scanner Power Supply and the Exit Module Control
Board. The 8860 and 8860MFP use different Electronics Modules. If a component of the Elec-
tronics Module fails, and service is necessary, replace the entire Electronics Module, with the
exception of the NVRAM, RAM memory, the Configuration Card, and either the Flash or Hard
drive; no individual board troubleshooting procedures or tests are necessary.
NOTE: If the system encounters certain fault conditions, the system may reboot up to three
times before displaying an error code. This is an attempt to correct the problem and reduce the
number of unnecessary service calls.
Following the suggested troubleshooting procedures in the specified sequence generally pro-
vides better test coverage than performing tests in a different order.
If either the Scanner turns on or the Exit Module initializes, the Scanner Power Supply is oper-
ational. If the Scanner turns on, but the Exit Module doesn't initialize properly, then the Power
Supply may be operational, but the Exit Module Control Board may be malfunctioning.
NOTE: On the 8860MFP, the image processor board enables the Scanner Power Supply and
communicates with the Exit Module, Scanner, DADF, and Control Panel. A faulty image proces-
sor board can make it appear as if other subsystems are at fault.
FDI Equipped Systems
The Foreign Device Interface works by interrupting the Tray Present sensor when no credit is
reported by the installed coin or card input. As Tray 2 has the highest priority, the message
"Tray 2 Missing" appears on the Control Panel of the 8560MFP whenever there is no credit
present.
System Ground Integrity
Intermittent or missing ground connections can result in system interference. As examples:
• Blank or intermittent Control Panel display
• I/O Board errors
• False jam reporting
• Erroneous thermistor readings
• Damage to the electrical boards
Key Ground Connections
The following illustration shows the grounding points in the Print Engine. There is also a ground
point on the Backframe. Check that these grounding points are in contact with the frame.
Diagnostics
Electrical Troubleshooting
09/2007
6-36
Figure 1 System Grounds
Phaser 8860/8860MFP Service Manual
Initial Issue