Left-Side Door Open Message When It Is Not; High Temperature Error; Low Temperature Error - Tektronix Z740/N - Phaser 740 Color Laser Printer Service Manual

Left-side door open message when it is not

The procedure for troubleshooting this problem applies to the Lower Tray Assembly
as well.
1.
Is the left door open switch, located in the lower-left back corner of the
printer, properly in place?
2.
Does closing the left door actuate the left door open switch?
3.
Is the left door properly in place? Replace the door if it does not operate
correctly.
4. Is the left door open switch's wiring harnesses properly connected to the
engine control board (CN3 – 24V interrupt)? In the case of the Lower Tray
Assembly, is the printer properly seated onto the Lower Tray Assembly with
good electrical connection. Try reseating the printer. Check the lower
feeder's wiring harness to the engine control board at connector CN19.
5. Replace the left door open switch.
6.
Replace the engine control board.

High temperature error

1.
Replace the power supply unit.
2.
Check the fans.
3. Replace the engine control board.

Low temperature error

1. Ensure the fuser is properly installed.
2.
Check the fuser's connection and wiring.
3.
Check to see if the fuser's thermo-fuse is open. With an ohmmeter, measure
the top two pins of the fuser's connector. For 110 VAC fuser you should
measure 1.6 ohms. For 220 VAC fuser you should measure 5.4 ohms. If it is
opened, replace the fuser.
4. Replace the fuser.
5. Replace the power supply unit.
6.
Replace the engine control board.
Service Guide
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