Adjustments For Videotex Monitor 008-0072370 - NCR PC4i Service Manual

ADJUSTMENTS
ADJUSTMENTS FOR VIDEOTEX MONITOR (BTX)
GENERAL
1. Pre-adjust the chassis
2. Perform only the adjustments here described
3. Do not change all other adjustments.
TOOL AND TEST PROGRAM
Flexible disk with Service Diagnostic Test Program,
HF adjustment tool.
TEST PREPARATIONS
Please don't readjust any potentiometer or coil not
described in the present procedure.
Load disk with Diagnostic Test Program and select the
monitor test for linearity.
HORIZONTAL WIDTH IN 23KHZ MODE
Adjust VR902 so that 105V is obtained at Test Point
99.
Adjust L552 to obtain 217 mm horizontal width.
Short circuit Test Point 8A and 8B
Adjust VR 505 so that an approxinately stable picture
is obtained.
VERTICAL HEIGHT AND LINEARITY
Adjust VR402 vertical height to 163 mm
Adjust VR 405 for vertical symmetry.
FOCUS
Select pattern for focus
potentiomneter for best average focus (positioned at
FBT)
CUTOFF AND BRIGHTNESS ADJUSTMENT
Adjust VR6R1, VR6B1, VR6G1
Cuttoff. Adjust
approximately dark screen for dark grey.
full brightness white raster. Switch RGB signal off
by removing signal connector.
side, a central horizontal line is then displayed.
Adjust VR654, screen positioned at FBT, so that a
7-18
adjustment
which results in
these p o t e n t i o m e t e r s
008-0072196
and adjust
Display a
Switch S651 to RGB
RGB
w i t h an