Lexmark T620 Service Manual page 115

4069-5XX/7XX
FRU
2 System Board
(No buttons work)
Operator Panel Display Service Check
SERVICE TIP: The printer has detected a problem with the system
board, operator panel cable or operator panel assembly if POST
does not complete and the printer emits 5 beeps and stops in a
continuous pattern until the printer is turned off. The operator panel
cable is an individual cable on some printers and a combination
cable assembly with the cover switch cable on later models.
Note: If the operator panel is operating properly except for a PEL or
a few PELS missing or broken, run the
from the hardware tests before continuing with this diagnostic
service check.
FRU
1 Operator Panel Cable
2 Operator Panel Display
blank, 5 beeps, LED Off
3 Operator Panel Display
blank, 5 beeps, LED On
4 Operator Panel All
Diamonds, no beeps
Action
Check the voltage at J16-2. The
voltage measures approximately
+5 V dc. If incorrect, replace the
system board. If correct, check the
continuity of the operator panel
cable. If incorrect, replace the cable.
If correct, replace the operator panel
assembly.
"LCD Test" on page 3-14
Action
Check for proper installation of the
cable at the system board (J16) and
at the operator panel. Check the
continuity of the operator panel
cable. If incorrect, replace the cable.
Check the voltage at J16 on the
system board. It measures
approximately +5 V dc. If incorrect,
replace the system board. If correct,
replace the operator panel assembly.
Check for continuity between J16-4
and ground. If correct, replace the
operator panel assembly. If incorrect,
replace the system board.
Replace system board.
Diagnostic Information
2-87