Inspecting The Power Supply Fuses; Testing For Shorted Drivers - Tektronix Phaser 360 Service Manual

Inspecting the power supply fuses

Testing for shorted drivers

Three fuses (F1 - F3) are mounted on the power supply.
1. Turn off the printer and remove the power cord.
2. Remove the right side cover to access the power supply and access the
fuse test point.
3.
With a VOM, determine that the fuses are functional.
If the fuses are good, but the printer's power supply does not output DC
voltages, proceed to the topic, "Testing for a shorted motor" on page 6-10.
If the AC power switch is on and there is no mechanical movement or LCD
activity after power-up diagnostics, or the LCD indicates that AC power has
been lost, check the AC sense signal on the power supply.
1. Turn the printer off.
2. Disconnect the DC power cable (J890) from the power control board
(this isolates all motors). Turn the printer on. If the rear panel LEDs
illuminate (indicating power), the power control board or its loads are
current-limiting the power supply. Go to Step 3. If no power is
evident (no lit LEDs), go to Step 4.
3. Turn off the printer. Reconnect the power cables to the power control
board (J890); then disconnect all load connectors at the top of the
power control board. Turn the printer on. If the rear panel LEDs still
do not illuminate, the power control board has a shorted driver and
must be replaced. If the LEDs do illuminate, isolate which motor r fan
is overloading the power control board and power supply by turning
off the printer and sequentially plugging each cable in one at a time
and turning the printer until the power supply is disabled. Replace
the defective component. Also refer to the next topic "Testing for a
shorted motor" on page 6-10.
4. Turn the printer off. Disconnect the two I
interconnect board. (This isolates all I/O board and their solenoid
drivers.) If the rear panel LEDs illuminate, isolate which I/O board is
shoring or which I
5.
If the power supply still does not work, replace the main board, since
it is easier to replace the main board than the power supply. As a last
resort, replace the power supply. Refer to the topic, "Power supply"
on page 8-10.
Note The power supply must have a minimum load to operate. The main
board provides this loading with four large ballast resistors.
2
C cable is bad.
Troubleshooting
2
C bus cables from the
Service Manual
6
6-9