Lexmark W820 Service Manual page 301

Removal
1.
If you are able to access Diagnostics Mode, then enter Diagnostic to read the print
engine usage logs. Write down the print count for each category.
2.
Remove the ESS Cover.
3.
Remove the ESS PWB.
4.
Disconnect J400, J401, J402, J403, J408, J409, and J411 from the MCU PWB.
5.
Remove the six screws securing the MCU PWB to the ESS Assembly.
6.
Lift the MCU PWB out of the ESS Assembly.
7.
Remove the U9 EEPROM from the MCU PWB and retain.
WARNING: Wear an electrostatic wrist strap and use caution when working with the
MCU PWB. Static electricity can damage the sensitive electronics of the MCU. Handle
the MCU PWB by the edges of the PWB or by the plastic connectors mounted on the
board. Never touch any of the ICs that are mounted on the PWB.
Replacement
1.
Install the U9 EEPROM from the old MCU PWB on the new MCU PWB.
1.
Reinstall the MCU PWB onto the ESS Assembly. Align the PWB so J406 faces the
ESS PWB location.
2.
Use two screws to secure J406 to the Assembly.
3.
Use six screws to secure the MCU PWB to the ESS Assembly. Do not fully tighten
the screws.
4.
Slide an ESS PWB into the ESS Assembly until the P/J on the ESS PWB mates with
J406 on the MCU PWB.
5.
Tighten the six screws securing the MCU PWB to the ESS Assembly.
6.
Reconnect J400, J401, J402, J403, J408, J409, and J411 from the MCU PWB.
7.
Reinstall the ESS Cover.
8.
Enter Diagnostic and take the values you took from the old MCU usage logs and
write them to the new MCU usage logs.
4025-XXX
4-93
Repair Information