Accuprint AP42CL 8000, Service Manual

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94MS42 Rev. B1 S/W Ver 2.06 13-15
Lamp Head Blowers
• The lamp head blowers are controlled by the printed circuit board to
provide the correct cooling to the lamp. During warm-up, the blowers
are off or run very slowly. At idle and during low exposure, the blowers
vary in speed. Both at high exposure and cool-down the blowers run at
full speed.
• A symptom of a defective blower would be: during high power exposure,
after approximately 10 seconds, the lamp extinguishes and requires 2 to
4 minutes to restart. One blower will speed up to compensate for the
defective unit or low power. When the unit switches to high power, the
additional heat causes one of the lamp thermostats to open. (See also
Interlock System for information on the thermostats.)
• To test the blowers, turn the power supply main switch on then off. During
the cool-down cycle, place a piece of paper over each intake vent located
on the lamp end. The paper should be drawn to the lamp end. If one lamp
end does not draw, that blower is suspect.
• To replace the blower in the lamp head, see section Opening Lamp Head.
Blown Fuse on PC Board
• If the fuse blows on the printed circuit board, check if the fuse is a 5 amp
fuse.
• The printed circuit board drives five or six circuits: the lamp head blowers,
shutter motor, power supply blower, and the relays. To find the cause,
unplug the unit and replace the fuse; then disconnect the wires to the
lamp head on terminals 5 and 6, and disconnect one of the wire nuts
connecting the blower in the power supply. The relay coils rarely cause
any problem.
• Plug in the unit and turn on the power switch for 10 seconds. If the fuse
blows, the problem is either: the power supply blower, the p.c.board or
in one of the relay coils. Unplug the unit and reconnect the red wire to
the terminal strip. Plug in the unit and turn on, then off. The shutter
should now turn. If the fuse blows, the problem is in the shutter motor or
wiring to the motor. Unplug the unit and connect the blue wire to the
terminal strip. Turn on the unit, then off for the cool-down cycle to test
the lamphead blowers. If the fuse blows during this test, the problem
could be with either of the two blowers in the lamp head. Normally,
when the coil on a blower fails, the coil will become discolored. See
section Opening Lamp Head. If the fuse has not blown throughout the
test, the power supply blower is suspect.