Accuprint AP42CL 8000 Service Manual page 116

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14-2
• You must be able to reach up, place your fingers against the safety glass
and there must be play front to back and side to side. Otherwise the glass
does not have room for expansion and will more than likely shatter under
use.
C NEVER operate the light source without the safety glass in
place.
4) Check the beau plug at the lamphead. Make sure it is pushed in all the
way. The most likely problem caused by a loose beau plug is an erratic
shutter operation or an open safety interlock circuit.
Just push in on the beau plug while rocking it up and down to make sure
it is in all the way.
5) Check the lamphead interlock circuit. Remove or lower the safety glass.
Turn the power supply on. Check for 120V~ from terminal 4 to terminal
10; when the glass is reinstalled, the voltage should go low. (See Interlock
System for operation.)
With the interlock open what should happen is the shutter should close
and the power supply blower should come on, that's all. After you remove
the glass and you turn on the power supply, if the light source comes on
turn power off immediately and determine what is shorting out and
bypassing the safety interlock circuit. If this does happen it is possible
that the safety interlock circuit is shorting to ground. On older light sources
this condition would burn up the autoformer. On newer light sources this
condition will blow the 3A slow blow fuse on the dividing wall below
the wiring harness.
6) Check input voltage with the power off at terminals 12 & 14. Then with
power on, intensity level on high, and manual expose set on, check the
voltage again. If the voltage drops more than 6 V~, the incoming power
is most likely a problem.
You can do checks 6 and 7 at the same time. Write down the voltage that
you get before turning power on and after turning power on but before
the light source completes the warm up cycle. This is maximum amperage
draw so the voltage will show maximum drop.
If the voltage in check 6 drops more than 6V~ the incoming power is a
problem and it can not be corrected in the power supply (there is nothing
you can do in the power supply to correct bad voltage from the wall).
7) Check input voltage to the PC board with the power off at pins 1 & 2 (see
p.c.board layout for pin location). Then with power on, intensity level
on high, and manual expose set on, check the voltage again. If the voltage
drops more than 6 V~, the autoformer is most likely a problem.
• If and only if the voltage on 12 and 14 in step 6 is good can you say that
the autoformer is definitely bad, if the voltage on 12 and 14 in step 6 is
bad you can not get a correct reading for step 7.
94MS42 Rev. B1 S/W Ver 2.06