Print Engine Troubleshooting; Printer Will Not Power Up - Tektronix Z780N - Phaser 780 Color Laser Printer Reference Manual

Print engine troubleshooting

Printer will not power up

When you switch on the printer, the control panel does not light, the fans do not
rotate, the carousel motor does not cycle, and the printer does not go into warm-
up.
1.
110VAC IN Check
a. Inspect the AC Power Cord. Is the AC Power Cord plugged into the
printer, and is the other end plugged into an AC wall outlet?
b.
Check the voltage at the AC wall outlet. Is there approximately
110 VAC (or 220 VAC if the printer is the 220 VAC model) at the AC
wall outlet?
c.
Remove the rear cover.
d. Measure the voltage between the two low voltage power supply
solder points located next to the AC power jack. Is there 110 VAC
between the two points?
2.
Low voltage power supply check
a.
Measure the voltage between P33-3 on the low voltage power
supply and frame ground. Is there +5 VDC between P33-3 and
frame ground. If not, replace the low voltage power supply.
a. Check for +24VDC between P32-3 on the low voltage power supply
and frame ground. Replace the low voltage power supply. Check
for +24VDC between P32-8 and frame ground. If voltage is at pin 3
but not at pin 8, check the front cover, fuser and paper feeder
interlock switches. Is there +24VDC between P32-11 and frame
ground? If not, replace the power supply. Check for a short in the
24 volt components (particularly on the paper feed motor circuit
board).
3.
Low voltage power supply loading check
a. Disconnect P32 and P33 from the low voltage power supply.
b.
Measure the voltage between P33-3 on the low voltage power
supply and frame ground, and between P32-11 on the low voltage
power supply and frame ground. Is there +5 VDC between P33-3
and frame ground, and is there +24 VDC between P32-11 and frame
ground? If not, replace the low voltage power supply.
4.
Engine control board loading check
a.
Reconnect P32 and P33 to the low voltage power supply.
b. Refer to "Wiring Diagrams" on page 185 and one by one disconnect
components that are connected to the engine control board.
40 Phaser 780 Color Printer