Pentax EPK-P, Service Manual

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6.3 Electrical adjustment
Preparation
Set a jumper to STB2 to disengage the lamp internal lock switch, and set Jig mode by putting a jumper to
STB3 . Refer to Photo-5.
Note: When opening the cover, it is necessary to remove the screw which is available under the lamp house lid.
6.3.1 Iris adjustment (necessary when the iris unit or Process board was replaced)
6.3.1-1 Hole element current adjustment
1) Connect the probes of the meter to TP25 (+) and TP26 (common).
2) Adjust VR500 so that the voltage attains +/-20mV .
6.3.1-2 Iris position adjustment
1) Press “ EXPOSURE CONTROL ” button on the front panel to select the iris mode “ MANUAL ”.
2) Press “ BRIGHTNESS down ” button on the front panel repeatedly until the brightness level becomes
“ -5 ”.
3) Enter key command “ Ctrl+J ” (common between NTSC & PAL) to show the color bar chart.
4) Adjust VR501 so that the edge of the iris plate just touches Close position stopper bar (Left one as
seen from the lamp side). Refer to Photo-6.
5) Press “ BRIGHTNESS up ” button on the front panel repeatedly until the brightness level becomes “ +5 ”.
6) Enter key command “ Ctrl+J ” (common between NTSC & PAL) to show the color bar chart.
7) Adjust VR502 so that the edge of the iris plate just touches Close position stopper bar (Right hand side
one as seen from the lamp side). Refer to Photo-6.
8) Confirm if the iris plate stays in about the center between the two stoppers after selecting the
brightness “ +/-0 ” and the color bar chart is displayed by entering the key command “ Ctrl+J ”. Turn off
and on the unit and turn on the lamp for the next confirmation.
9) Connect a scope and check if the iris properly works in accordance with the iris manual operation
(changing the brightness by pressing BRIGHTNESS button).
10) Check if the iris properly works in iris auto mode.
11) Turn off the unit and disconnect the jumpers set before.
12) Put back the cover and perform the electrical safety tests.
VR500
VR502
VR501
TP26
TP25
STB2
STB3
Photo-5 VR & TP on Process board
Close position stopper Open position stopper
Edge of Iris plate
Iris plate
Photo-6 Iris position adjustment
The iris is located behinds the scope
connector and it is visible from above after
removing the bridge plate (black plastic one).