Printing Too Light Or Too Dark; Image Is Offset Or Cut Off - Tektronix Phaser 440 Service Manual

6
Troubleshooting
6-16 Phaser 440 Color Printer

Printing too light or too dark

1.
Ensure that the PAPER/TRANSPARENCY switch on the side of the
tray is set to the correct setting.
2. Ensure that the thermal head voltage setting, determined by DIP
Switches 2-1 through 2-4, is correct for the resistance of the thermal
head. Refer to the Chapter 9 topic "Adjusting for best print quality"
on page 9-16.
3. Measure the voltage being supplied to the thermal head (refer to the
earlier topic "Verifying power supply operation" on page 6-3). The
head voltage should measure between 13.5 to 15 VDC during
printing.
4. Ensure that the wiring harness leading to the transfer roll mark sensor
board is not nicked or damaged. A thermistor mounted on the board
"tells" the engine control board of the print engine's ambient
temperature. An erroneous thermistor value could cause the print
engine to use an incorrect thermal head voltage value for printing.
5. Ensure that the thermal head fan and two small internal fans runs
during printing to keep the thermal head from overheating during
printing. The fans blow upward.
6.
If the voltage supplied to the thermal head is correct and the DIP
Switch 2 setting is correct, then replace the thermal head. Refer to the
Chapter 8 topic "Thermal head" on page 8-18.
7. If printing still does not improve, replace the engine control board.
Refer to the Chapter 8 topic "Engine control board" on page 8-40.

Image is offset or cut off

1.
Check the application for the correct image sizing.
2. Ensure that Letter, A4 or Letter Extra is the selected paper size.