Xerox Phaser 840 Service Manual page 271

III. Blank Display, Front Panel Lights ON, Rear LED flashing
ADDITIONAL CLUES
SDRAM Error Codes (2-6) See page 29 in the
Phaser 840/850 Service Quick Reference Guide for
more information.
1.
Condition started
after recent
upgrade.
2.
Was working OK,
then failed.
NVRAM Error Codes (9,10) See page 30 in the
Phaser 840/850 Service Quick Reference Guide for
more information.
3.
Recently swapped
main board
(9 = NVRAM Chip,
840 only)
(10 = 8-pin Boot
ROM).
4.
Other error code.
Record here
Confirm that all DIP
switches are up
PROBABLE ROOT CAUSE
A. The Memory DIMM not
seated correctly.
B. Connection problem with
code DIMM
C. Unsupported or defective
memory DIMM.
D. ESD damage to main
board.
A. Connection problem with
code DIMM.
B. Memory DIMM became
defective.
A. NVRAM (840 only) or
Boot ROM socket empty
or chip has bent leg.
B. NVRAM (840 only) or
Boot ROM defective.
A. Depends on error code.
NOTE: On the Z850, the SDRAM
error codes will also flash on the
front panel error LED.
ACTIONS (follow in order)
1A.Reseat the memory DIMM.
1B.Reseat the Code ROM DIMM.
1C.Replace the memory DIMM.
1D.Replace the main board.
2A.Reseat the Code ROM DIMM.
2B.Replace the memory DIMM.
3A.Swap part from old board or
check for bent leg.
3B.Replace with new part.
4A.See page 29 of Error Code
topic in the Phaser 840/850
Service Quick Reference Guide.
Appendix 255