Service manual

Service Manual 6-15
Troubleshooting 6
10. Perform the Chapter 9 procedure “Adjusting for best print quality” on
page 9-14.
11. Replace the thermal head. This is explained in the Chapter 8 topic “Thermal
head” on page 8-17.
Not printing
The printer processes a sheet of paper, but no image is printed on it.
1. Ensure that the thermal head temperature-adjust DIP switches are correctly
set for the resistance of the thermal head. Refer to the Chapter 9 topic
“Adjusting for best print quality” on page 9-14."
2. Ensure that the thermal head power and data cables are properly connected.
3. Measure the power being supplied to the thermal head (refer to the earlier
topic “Verifying power supply operation” on page 6-3). If no DC voltage is
being supplied to the thermal head, then troubleshoot the power supply and
the wiring harness leading to the thermal head.
4. Inspect the data wiring harness leading from the engine control board to the
thermal head for nicks, cuts, or damage.
5. If everything checks out in the previous steps you can assume that the data
drivers on the print engine control board are bad; replace the print engine
control board. Refer to the Chapter 8 topic, “Engine control board” on
page 8-39.