IBM 6400 series Maintenance Manual page 114

No action required.
WAITING FOR PROGRAM DOWNLOAD
1. Emulation download mode has been activated, but program download has not
yet begun.
No action required.
Black squares on operator panel display
1. Power off the printer. Remove the paper guide assembly or pedestal top cover.
Disconnect the operator panel cable from the panel and from J110 on the CMX
controller board. Check continuity of the cable. (See Appendix A.)
Replace the operator panel cable if it fails continuity test. Connect the
cable. Power on the printer. If the symptom appears, replace the operator
panel.
2. If the printer has the coax/twinax expansion board, check the adapter connection
to the CMX controller board.
Make sure the 60-pin expansion adapter is correctly seated in the CMX
controller board connector J111 and the coax/twinax expansion board.
3. Power off the printer. Make sure the flash memory is seated properly in J10 and
J11. Regardless of memory configuration, J11 must be used.
Reseat flash memory.
4. Power on the printer.
If black squares appear on the LCD, the flash memory could be blank.
Replace the flash SIMM in J11 with a new flash SIMM with the boot
program installed.
5. Power on the printer.
If black squares appear on the LCD, replace the CMX controller board.
Characters or dots are missing, smeared, too light, or too dark
1. Check the forms thickness lever: if it is set too loose or too tightly print quality can
be affected.
Set the forms thickness lever to match the thickness of the paper being
used.
2. Check the paper tension between the tractors.
114 Troubleshooting