Lexmark C750 Service Manual - Page 134

Lexmark C750 Manual

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5060-00x Step 3 Actions and questions Press the TMC pin in the black cartridge contact assembly make sure it actuates the TMC switch on the developer HVPS. When the TMC pin is pressed 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 black TMC switch on the developer HVPS board actuate properly when the TMC pin is pressed? Yes Replace the cartridge. No Go to step 4 4 Check the developer HVPS board to make sure it is not cracked or broken. Is the developer HVPS board cracked or broken?' Replace the developer HVPS board assembly. Go to step 6 Go to step 5 5 Check the mounting of the developer HVPS. Make sure the screws that mount the power supply are properly tightened and the board is positioned and mounted correctly. Is the developer HVPS mounted correctly? If the board is incorrectly installed, install it correctly. Make sure all the mounting screws are tightened. Recheck the printer to see if a 943 error is still displayed. Correctly connect the cable. 6 Make sure the developer HVPS cable is correctly installed on the developer board assembly. Is the cable correctly installed? Go to step 7 7 Make sure the developer HVPS cable is correctly installed at J20 on the engine board. Is the cable properly installed? Go to step 8 Correctly connect the cable. 8 Check the voltage at connector J20-1 on the engine board while pressing the black TMC pin in the cartridge contact assembly. Does the voltage change when the pin is pressed? Replace the engine board assembly. Go to step 9 9 Check the voltage at connector J20-1 when the black TMC switch is pressed. Does the voltage measure approximately +3.3 V dc? Go to step 10 Go to step 11 10 Check the developer HVPS to engine board cable for damage, broken connections, or wire and shorts between adjacent pins. Are there any signs of damage to the cable? Replace the cable. Replace the developer HVPS board assembly. 11 Disconnect the developer HVPS cable from connector J20 on the engine board. Measure the voltage on connector J20-1 on the engine board. Does the voltage measure approximately 0 V dc? Replace the engine board assembly. Replace the developer HVPS and developer HVPS to engine board cable. 2-100 Service Manual

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2-100
Service Manual
5060-00
x
3
Press the TMC pin in the black cartridge contact
assembly make sure it actuates the TMC switch on the
developer HVPS. When the TMC pin is pressed 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 black TMC switch on the developer HVPS
board actuate properly when the TMC pin is pressed?
Replace the
cartridge.
Go to step 4
4
Check the developer HVPS board to make sure it is not
cracked or broken.
Is the developer HVPS board cracked or broken?‘
Replace the
developer HVPS
board assembly.
Go to step 5
5
Check the mounting of the developer HVPS. Make sure
the screws that mount the power supply are properly
tightened and the board is positioned and mounted
correctly.
Is the developer HVPS mounted correctly?
Go to step 6
If the board is
incorrectly
installed, install it
correctly. Make
sure all the
mounting screws
are tightened.
Recheck the
printer to see if a
943 error is still
displayed.
6
Make sure the developer HVPS cable is correctly
installed on the developer board assembly.
Is the cable correctly installed?
Go to step 7
Correctly connect
the cable.
7
Make sure the developer HVPS cable is correctly
installed at J20 on the engine board.
Is the cable properly installed?
Go to step 8
Correctly connect
the cable.
8
Check the voltage at connector J20-1 on the engine
board while pressing the black TMC pin in the cartridge
contact assembly.
Does the voltage change when the pin is pressed?
Replace the engine
board assembly.
Go to step 9
9
Check the voltage at connector J20-1 when the black
TMC switch is pressed.
Does the voltage measure approximately +3.3 V dc?
Go to step 10
Go to step 11
10
Check the developer HVPS to engine board cable for
damage, broken connections, or wire and shorts
between adjacent pins.
Are there any signs of damage to the cable?
Replace the cable.
Replace the
developer HVPS
board assembly.
11
Disconnect the developer HVPS cable from connector
J20 on the engine board. Measure the voltage on
connector J20-1 on the engine board.
Does the voltage measure approximately 0 V dc?
Replace the engine
board assembly.
Replace the
developer HVPS
and developer
HVPS to engine
board cable.
Step
Actions and questions
Yes
No