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6. VCO Free run adjustment
Power supply
1) Adjust power supply voltage so that CP172 voltage becomes 11.5 ± 0.05V.
2) Connect CP756 and CP757 (VCC4-2).
3) Connect a frequency counter to CP181 and adjust VR751 so that the counter reading is 15.73 ± 0.1kHZ.
7. V-COM coarse adjustment
Power supply
1) Adjust power supply voltage so that CP172 voltage becomes 11.5±0.05V.
2) Connect an oscilloscope to CP802. Observing the oscilloscope, adjust
VR850 so that pulse amplitude is 4.0±0.1V.
3) Adjust VR801so that pulse's "H" level is 0.1 ± 0.5V.
8. V-COM fine adjustment
Pattern generator
1) Adjust power supply so that CP172 voltage become 11.5 ± 0.05V.
2) Apply black raster signal to the set through Video Input terminal and
turn the brightness control dial all the way to the maximum position.
3) Set the adjustment jig on the monitor as shown on the figure above.
4) observe the sensor amplifier output with an oscilloscope. Adjust VR801 so
that 60Hz component becomes minimum.
Set + monitor
CP756
Input
DC12V
Set + monitor
Input
DC12V
Photo diode
Input
Video
Set + monitor
— 4 —
CP757(VCC4-2)
Frequency counter
Output
CP181
Digital multimeter
Output
CP802
DClevel=0.1 ± 0.5V
Photo sensor amplifier
Minimize the amplitude.
4.0 ± 0.1V
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