Troubleshooting; System Power-Up Sequence - Tektronix Phaser 440 Service Manual

Chapter
6

System power-up sequence

Troubleshooting

This chapter discusses troubleshooting a Phaser 440 printer. Troubleshooting is
discussed with two approaches:
A step-by-step verification procedure that systematically confirms that
particular components of a printer are properly functioning until a
problem is found.
A symptom/cause scheme that lists particular printer failures and
error codes and their possible causes.
The following lists the chain of events that occur when you turn on a printer.
You can follow this list as one means of determining if the printer is operating
correctly.
Power switch turned on:
1. The front panel LEDs are momentarily lighted and then turned off.
The POWER LED remains on all the time since it is wired to +5 VDC.
The READY LED flashes during the printer initialization.
2.
The thermal head lift motor energizes to raise the thermal head into its
standby position if it is out of position. The position is sensed by the
thermal head position sensors.
3. The transfer roll feed motor energizes and advances the transfer roll
one set of color panels until a yellow band is detected by the transfer
roll mark sensors. This also occurs each time the transfer roll is
removed and reinstalled in the printer.
4.
The drum motor rotates the drum about one and one-half revolutions.
5. The drum is reversed for half a revolution. At the same time, the
paper-feed motor runs for about 3 seconds. This action ejects any
sheet of paper that may have remained in the printer following an
abnormal power-down.
Service Manual 6-1