IBM 6400 series Maintenance Manual page 122

Replace the paper feed motor if paper does not move in both directions.
9. Power on the printer. Press Form Feed and View several times and check that
paper moves in both directions.
Replace the CMX controller board if paper does not move in both
directions.
Printer does not complete IML
NOTE: Power-on initialization is explained on page 151.
1. Power off the printer. Remove the paper guide or pedestal top cover. Check that
all cables are connected to the CMX controller board.
Reseat all cable connectors on the CMX controller board, especially
connectors P106 and P107.
2. If the printer has the coax/twinax expansion board, verify that the correct
microcode is loaded in the machine. If the printer does not have the coax/twinax
expansion board, go to step 6.
Download CT emulation software.
3. Power off the printer. Check that the user has enough flash memory installed to
handle his emulation software. (See Figure 34 on page 226, and Boot
Diagnostics Menu on page 142.)
Install flash memory and download emulation software.
4. Check the coax/twinax adapter connection to the CMX controller board.
Make sure that J111 is correctly seated between the CMX controller
board and the coax/twinax expansion board.
5. Power up the printer.
If the printer does not successfully complete IML, replace the coax/twinax
expansion board.
6. Power up the printer.
If the printer does not successfully complete IML, replace the power
supply board.
7. Power up the printer.
If the printer does not successfully complete IML, replace the CMX
controller board.
122 Troubleshooting