Casio TV-880B Service Manual & Parts List page 6

• Adjustment
Monitoring HDB (CP305) with a frequency counter, adjust VR700 so that the frequency is 15.734 ±
0.1 [kHz].
• Caution
(1) Disconnect the wire between SYF terminal and VCC2-7. Applying IF signal make sure that
synchronization is normal on the display.
(2) Use input signal pattern conforming CCIR standard.
4. Contrast adjustment
• Conditions
(1) Signal
Broadcasting system: M/M
Color system: NTSC color bar
(2) Signal level
Input electric field: 70 dBµ (terminated with 75-ohm resistance), P/S = 10 dBµ
(3) Other conditions
US IF input (input electric field should be terminated with 75-ohm resistance).
Apply voltage of Vcc1-1 = 5.0 ± 0.05 [V]
• Adjustment
Connect color terminal (CP320) to GND (CP300) so that screen becomes black and white. Adjust
contrast pot VR300 so that the voltage between pedestal level and white level of B signal (CP740) is
0.80 ± 0.05 [Vp-p].
• Caution
(1) Make sure that there is no distortion on the waveforms.
(2) Connect COLOR terminal of Chroma IC (M52042FP) to GND.
(3) Monitor the B output signal with an oscilloscope via a low-pass filter (C = 2700 pF, R = 100 ohm).
5. TINT pot adjustment
• Condition
(1) Signal
Broadcasting system: M/M
Color system: NTSC color bar
(2) Signal level
Input electric field: 70 dBµ (75-ohm termination), P/S = 10 dB
(3) Other conditions
US IF input (input electric field should be terminated with 75-ohm resistance).
Apply voltage of Vcc1-1 = 5.0 ± 0.05 [V]
• Adjustment
Observing B output signal (CP740) with an oscilloscope, adjust TINT pot VR301 so that amplitude
difference between two center pulses is 0.1 [V].
• Caution
Do not connect COLOR terminal to GND.
Monitor B output signal with an oscilloscope via a low-pass filter (C = 2700 pF, R = 100 ohm).
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