Safety Interlocks - Tektronix Phaser 550 Service Manual

Inspecting the power supply fuses
The 115 VAC power supply features a 10 A and 6.3 A fuse. The 220 VAC power
supply fuse uses a 8 A fuse.
1. Turn off the printer.
2.
Remove the power supply as explained in the Chapter 8 topic, "Power
supply" on page 8-11.
3. As explained in the Chapter 8 topic, "Power supply fuse" on
page 8-13, remove the power supply cover to access the fuse.
4. Visually, and with a VOM, check to determine that the fuse is in
working order.
If the fuse is good, but the printer's power supply does not output DC voltages,
proceed to the next topic, "Testing for a shorted motor."

Safety interlocks

The printer features four safety interlock switches:
Front door/right side door-opened switch.
Left door-opened switch.
Fuser installed switch (located under the fuser cooling fan duct
housing).
Optional Lower Tray Assembly door switch.
When any of the switches are opened, the +24 VDC supply to the motors is shut
down, as well as the high-voltage power supply.
1. Turn off the printer.
2.
With a VOM, set to measure resistance, test each switch when it is
opened and closed.
3. Inspect each switch's wiring harness for pinches, nicks or open
connections.
If you find a switch that is defective, replace it.
If the switches work correctly and the DC voltages are correct, then the problem
may be an opened or otherwise faulty motor. Proceed to the topic, "Testing
motor resistances" on page 6-7.
Troubleshooting
Service Manual 6-5
6