Lexmark C78x Service Manual page 105

Step Actions and questions
2 Check the TMC pin (B) in the magenta cartridge
contact assembly to make sure it moves freely.
Does the pin move freely?
3 Go to the "BASE SENSOR TEST" on page
check the magenta TMC sensor. When you press the
TMC pin in the magenta cartridge contact assembly,
make sure it actuates the TMC switch on the developer
HVPS. When the TMC pin is pressed in, you hear a
click when the switch actuates. Check for mechanical
interference between the contact block and the
developer HVPS.
Note: You may need to turn the printer off to hear the
click.
Does the magenta TMC switch on the developer HVPS
board actuate properly when the TMC pin is pressed?
4 Check the developer HVPS board to make sure it is not
cracked or broken.
Is the developer HVPS cracked or broken?
5
Check the mounting of the developer HVPS. Make
sure the screws that mount the power supply are
properly tightened down and the board is positioned
and mounted correctly.
Is the developer HVPS mounted correctly?
6 Make sure the developer HVPS cable is correctly
installed on the developer board assembly.
Is the cable correctly installed?
7 Make sure the developer HVPS cable is correctly
installed at J6 on the system board.
Is the cable properly installed?
Check the voltage at connector J6-6 on the system
8
board while pressing the magenta TMC pin in the
cartridge contact assembly.
Does the voltage change when the pin is pressed?
B
3-24, and
Yes No
Go to step 3 Replace the
cartridge contact
assembly. See
"Cartridge
contact
assembly
removal" on
page
Replace the Go to step 4
cartridge.
Go to step 6 Go to step 5
Replace the If the board is
developer HPVS. incorrectly
See "Developer installed, install it
HVPS board correctly. Make
removal" on sure all the
page 4-39. mounting screws
are tightened
down. Recheck
the printer to see
if a 941 Error is
still displayed.
Go to step 7 Correctly connect
the cable.
Go to step 8 Correctly connect
the cable.
Replace the Go to step 9
system board.
See "System
board removal"
on page 4-90.
Diagnostic information
5061
4-35.
2-61