Lexmark C734dn Service Manual

Diagnostic information 2-131
5026
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Operator panel service check
One or more operator panel buttons fail
Operator panel display blank, five beeps, and LED is off
Service tip: The printer has detected a problem with the system board, the operator panel assembly cable (part
of the top cover access assembly), or the operator panel assembly if POST does not complete. The printer emits
five beeps, and then sticks in a continuous pattern until the printer is turned off.
Operator panel display blank, five beeps, LED on
Service tip: The printer has detected a problem with the system board, the operator panel assembly cable (part
of the top cover access assembly), or the operator panel assembly if POST does not complete. The printer emits
five beeps, and then sticks in a continuous pattern until the printer is turned off.
Step Questions / actions Yes No
1 Run the Button Test. See“Button Test” on
page 3-12 in Diagnostics mode.
Did any of the buttons fail the test?
Replace the operator panel
assembly. See “Operator
panel assembly removal”
on page 4-24.
Go to step 2.
2
Disconnect the operator panel assembly
cable from JOPP1 on the system board, and
then measure the voltage on pin 6 and
ground.
Does the voltage measure approximately
+3.3 V dc?
Replace the operator panel
assembly. See “Operator
panel assembly removal”
on page 4-24. If this does
not fix the problem, replace
the top cover access
assembly. See “Top
access cover assembly
removal” on page 4-40.
Replace the system board.
See “System board
removal” on page 4-153.
Step Questions / actions Yes No
1 Is the operator panel assembly cable properly
installed at system board JOPP1 and at the
operator panel assembly?
Go to step 2. Reinstall the cable.
2
Measure the voltage between JOPP1 pin 2
and ground on the system board.
Is the voltage approximately +5 V dc?
Go to step 3. Replace the system board.
See “System board
removal” on page 4-153.
3
Check continuity of the operator panel
assembly cable.
Is there continuity?
Replace the operator panel
assembly. See “Operator
panel assembly removal”
on page 4-24.
Replace the top cover
access assembly. See
“Top access cover
assembly removal” on
page 4-40.
Step Questions / actions Yes No
1 Check for ground between JOPP1 pin 4 and
ground.
Is the voltage approximately 0 V dc?
Replace the operator panel
assembly. See “Operator
panel assembly removal”
on page 4-24.
Go to step 2.
2
Check the operator panel assembly cable.
Is the cable damaged?
Replace the top cover
access assembly. See
“Top access cover
assembly removal” on
page 4-40.
Replace the system board.
See “System board
removal” on page 4-153.

Lexmark C734dn Specifications

General

Brand	Lexmark
Model	C734dn
Category	Printer
Language	English