Lexmark 4059-XXX - Manual (Page 61)

Diagnostic Information 2-34
4059-XXX
9 Engine Board Turn the printer off and disconnect
all the cables from the engine board.
Check for +5 V dc at the engine
board test point. 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.
Service Tip: Check the engine board
for burn marks or other damage,
especially R20,R21, R22 and R23
located next to the upper left engine
board mounting screw. If this screw
is overtightened it might deform the
engine board shield and cause it to
short out these resistors.
FRU Action