Check; Intermittent Problem Service Check - Lexmark 2380 - Forms Printer B/W Dot-matrix Service Manual

Intermittent Problem Service Check

FRU/Symptom
1 The machine
sometimes fails
before POST is
complete.
2-20
Action
Check for the following:
1. Loose connectors. Reconnect all
connectors to the main and sub logic
boards.
2. Electrical noise or static discharge.
Check the following items:
• Power supply ground.
• Machine frame ground.
• Printer interface cable is grounded and
shielded.
• If the upper feed roll shaft does not have a
ground spring, install P/N 1368036.
3. Intermittently low voltages. Check for ac and
all dc voltages and short circuits on the main
and sub logic boards.
a. Check the customer's outlet voltage and
ensure that it is within tolerance.
b. Check the continuity of the power
cord.
c. Disconnect the power supply cable
from the connectors CN11 on the
main logic board and CN1 on the sub
logic board. Turn the printer power on
and check all dc output voltages at
CP11 and CP1.
Ensure the output voltages are:
CP11-1 (+26 V dc ±10%) & CP11-2 (GND)
CP11-3 (+5 V dc ±5%) & CP11-4 (Signal GND)
CP 1-1 (+26 V dc ±10%) & CP1-2 (GND)
CP 1-3 (+5 V dc ±5%) & CP1-4 (Signal GND)
If the voltages are not correct, replace the
Power Supply Unit.
If the failure remains, replace the main logic
board and sub logic board.
Note: When replacing the main logic board,
always reset the bidirectional print adjustment.
Refer to "Bidirectional Print Adjustment" on
page 4-5.