Power Failure Service Check - Lexmark 4227 - Forms Printer B/W Dot-matrix Service Manual

4227-300

Power failure service check

For more information see
on page 1-2.
FRU
1 Operator Panel
2 Power Supply
Fuse
"Voltage, ground, and continuity readings"
Action
If the operator panel or cable is damaged or
disconnected, the machine is completely
inoperable, except for the power supply fan
noise.
If the power LED is not on steady, check the
cable continuity and replace the cable or the
operator panel.
If the printer is completely inoperable,
disconnect the power cables from the main
logic board (CN11) and the sub logic board
(CN1).
Turn the power on and measure
+5 ± 0.5 V dc at the sub logic board cable
CN1-5 and +40 ± 4 V dc at CN1-1 and CN1-2.
If there is no voltage, check the internal fuse
before replacing the power supply.
A 634 Power Failure indicates that the +5 V dc
is OK but the +40 V dc is not. Power the printer
off, wait 10 seconds, and power back on. If the
634 reappears either the power supply has
failed or there is a short in a motor that uses
+40 V dc.
Diagnostic information
2-25