Lexmark W820 Service Manual page 154

Blank, Erratic, or Inoperative Operator Panel
The Operator Panel LCD is blank or displays garbled text, or the Operator Panel Keypad
does not respond to user input.
Step Actions and Questions
1 PRINTER STATUS TEST
Switch on printer power and wait 2 minutes for warm-up to
complete.
Use any application on the host computer to generate a few
prints.
Does the printer generate prints?
2 OPERATOR PANEL TEST
Enter Diagnostic Mode.
Does the display indicate diagnostic mode?
3 ESS PWB REPLACEMENT
Replace the
Is the problem still present?
4 The following printer FRUs and areas are associated with this
specific problem. One or more of these FRUs or areas may
have failed partially or completely. If you cannot isolate this
problem using the steps in this Service Check, replace each
FRU or troubleshoot each area listed below, one at a time, until
you isolate and solve the problem.
• Wiring and connectors linking the FRUs
• I/O PWB - Go to
The Printer Does Not Offset Paper
The offset function does not work or does not work correctly.
Step Actions and Questions
1 MAIN DRIVE ASSEMBLY TEST
Remove the Rear Cover Assembly.
Use the Print Test to check the Main Motor and the Main Drive
Assembly.
Does the Main Motor run and do the gears of the Drive
Assembly rotate normally?
2-58
Service Manual
"Controller Board (ESS PWB)" on page
"I/O PWB" on page
4025-XXX
4-94.
4-89.
Yes No
Go to step 2 Go to
"Inoperative
Printer" on
page 2-54.
Go to step 3 Replace the
"Operator
Panel" on
page 4-11
Replace the Problem
"Engine solved
Board (MCU
PWB)" on
page 4-92
Yes No
Go to step 2 Replace the
"Main Drive
Assembly"
on page 4-79