Intermittent Problem Service Check - Lexmark Forms Printer 2400 Service Manual

24xx

Intermittent Problem Service Check

FRU/Symptom
1 The printer
sometimes fails
before POST is
complete.
2-18
Service Manual
Action
Check for the following:
1. Loose connectors. Reconnect all
connectors to the logic board.
2. Electrical noise or static discharge.
Check the following:
• Power supply ground.
• Printer frame ground.
• Printer interface cable is grounded and
shielded.
3. Intermittently low voltages. Check for ac and
all dc voltages and short circuits on the logic
board.
a. Check the user'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 connector CN12 on the logic
board. Turn the printer power on and
check all dc output voltages at
CN12-1, CN12-2, and CN12-6.
Verify the following output voltages:
CN12 - 1 (+40 V dc ±10%)
CN12 - 2 (+40 V dc ±10%)
CN12 - 3 (GND)
CN12 - 4 (GND)
CN12 - 5 (Signal GND)
CN12 - 6 (+5 V dc ±5%)
CN12 - 7 (Power Save Mode)
• If the voltages are incorrect, replace the
power supply.
• If the failure remains, replace the logic
board.
Note: When replacing the logic board, always
reset the bidirectional print adjustment. See
"Bidirectional Print Adjustment" on
page 4-4.