Dc Power Service Check - Lexmark C77x Service Manual

DC power service check

The machine is partially operative, a motor turns, display is on, or the Power On LED may be on or off.
Step Actions and questions
1 Does the printer beep 5 times and the operator panel
display all diamonds?
2 DC power to system board—Turn the power off, and
disconnect the LVPS cable to J18 on the system
board. Turn the power on, and check the following
voltages on the LVPS cable:
J18-1 +3.3 V dc
J18-2 +3.3 V dc
J18-3 +5 V dc
J18-4 +5 V dc
J18-5 +24 V dc
J18-6 +24 V dc
J18-7 +24 V dc
J18-8 +3.3V dc
J18-9 Ground
J18-10 Ground
J18-11 Ground
J18-12 Ground
J18-13 Ground
J18-14 Ground
J18-15 Ground
J18-16 Ground
Note: All voltages are approximate values.
Are the voltages correct?
3 Unplug all cables from the system board, except
JOPP1, J18, and J20. See
page 5-7.
Does the printer power up and display a message?
4 Turn off the printer, and plug in the cable for the
component that is related to the error presented. For
example, for the 109.xx Service Printhead error, plug in
the black printhead JMMK1 and JMK1. Use connector
locations on "System board" on page
Repeat this step until the original DC power problem
occurs.
Does the DC power problem occur?
"System board" on
5-7.
Yes No
Go to "Operator Go to step 2
panel LCD/
status LED/
buttons service
check" on
page 2-88.
Go to step 3 Replace the
LVPS assembly.
See
assembly
removal" on
page
Go to step 4 Replace the
system board.
See
board removal"
on page
Check the cable If printer comes
and component to Ready,
that was last connect the
connected to remaining cables
system board for and print.
short.
Diagnostic information
5061
"LVPS
4-53.
"System
4-89.
2-75