Lexmark M410 - Optra B/W Laser Printer Service Manual page 47

4045-XXX
FRU
7 LVPS Fuse F1 - Continues
to blow after LVPS installed
in the printer.
8 LVPS
9 Engine Board
Action
Replace fuse F1 if necessary. Turn
the LVPS on/off switch Off and
connect the AC line cord and turn
the LVPS On.
CAUTION: Before checking fuse F1
turn the LVPS Off and disconnect
the AC line cord. Check fuse F1. If
the fuse is blown, replace the LVPS.
Remove the LVPS from the machine.
CAUTION: Before making any
measurements on the LVPS output
connector, observe all necessary
safety precautions before applying
AC power. Measure the voltages on
LVPS output connector CN1. If any
voltages are incorrect, replace the
LVPS.
Turn the printer off and disconnect
all the cables from the engine board.
Check for +5 V dc at TP5 test point
and +24 V dc at test point TP6 on
the engine board. If incorrect,
replace the FRUs in the following
order:
engine board
interconnect board
If correct, turn the printer off and
reconnect one cable at a time until
you find the defective assembly.
Service Tip: A short or low
resistance load that is attached to
the engine board can cause the
LVPS to overcurrent and shut the
+5 V dc supply down to 0 V dc.
Diagnostic Information
2-21