— 6 —
5.0 – 0.1 V
3.5 – 0.1 V
VCC1-1
IF signal
Signal
generator
Stabilizer
Oscilloscope
L-PCB
B output
CP308
22 K
Ω
VCC2-3
5. Contrast, Bright adjustment
• Conditions
(1) Signals
Broadcasting system: B/G
Color system: PAL color bar
(2) Signal level
Input electric field: 70
±
3 dB
µ
(terminated with 75
Ω
resistance), P/S = 10 dB
(3) Others
CCIR IF input (input electric field should be terminated with 75
Ω
resistance)
As to VIDEO signal, use signal source equivalent to TG7.
Supplying power should be VCC1-1 = 5.00
±
0.05 V
•
Adjustment
(1) Apply VCC2-3 (CP344) voltage on KILLER terminal (CP308) via 22 k
Ω
resistance.
(2) Triggering FRP signal (CP711), observe VB waveform (CP324) and adjust BRIGHT VR so that pedes-
tal-pedestal voltage becomes 5.0
±
0.1[V].
(3) Adjust VR303 so that VB (CP324) waveform's pedestal - white peak voltage is 3.5
±
0.1[V].
•
Caution
(1) Make sure that waveforms are not distorted.
(2) After the adjustment, disconnect VCC2-3 voltage from the killer terminal.
(Reference: Use white 75% for PAL color bar.)
(3) Do not move BRIGHT VR until TINT and COLOR adjustments are completed.
•
Block diagram
