Lexmark C77X, Service Manual

Page: 120 / 480

2-76
Service Manual
5061
AC and DC power service check
Before proceeding with this service check remove or disconnect any options that may be installed. Turn the
machine on. If it operates correctly, reattach one option at a time until the failing option is located.
Note: Set the voltage range switch to the proper power setting for the geographic area you are in.
Note: Before proceeding with this service check, turn the printer on, and check to see if the Power on LED on
the system board is turned on.
AC power service check
The printer appears to be inoperative when turned on with the Power on/Status LED off, the LCD
display is blank, the fuser lamps do not come on, and no motors turn.
Step Actions and questions Yes No
1 Is the LED turned on? Go to “AC power
service check”
on page 2-76
.
Go to “DC power
service check”
on page 2-77
.
Step Actions and questions Yes No
1 Main AC power—Make sure the printer is receiving
main AC power.
Is the printer receiving AC power?
Go to step 2 Inform the
customer that AC
power to the
printer is
incorrect.
2 AC power check (wall outlet)—Check the AC line
voltage at the AC outlet.
Is the AC line voltage correct?
Go to step 3 Inform the
customer that the
AC line voltage is
incorrect.
3 AC power cord
Is the power cord in good condition and correctly
installed?
Go to step 4 If the cord is in
poor condition,
replace the cord.
4 AC power check (AC line cord)—Check the AC line
voltage at the end of the AC line cord.
Is the AC line voltage correct?
Go to step 5 Replace the line
cord.
5 Low voltage power supply—Turn the power off, and
disconnect the LVPS at J18 on the system board.
Measure the voltages on J18-3 and J18-4. The voltage
should measure approxi5 V dc.
Is there approxi5 V dc on any of these
connector pins?
Replace the
system board.
See
“System
board removal”
on page 4-90
.
Replace the
LVPS assembly.
See
“LVPS
assembly
removal” on
page 4-53
.