Bright Adjustment (Vc-197 Baord); Contrast Adjustment (Vc-197 Baord) - Sony GV-A500 Service Manual

4. Bright Adjustment (VC-197 baord)

Set the D range of the RGB decoder used to drive the LCD to the
specified value. If deviated, the LCD screen will become blackish
or saturated (whitish).
Mode VTR stop
Signal 10-step stair-step signal or color bar
signal whose chroma and burst signals
are turned off
Pin 2 of CN802 (VG) of VC-197
Measurement point
board
Measuring instrument Oscilloscope
Adjustment page D
Adjustment address 52, 5D
Specified value A = 2.60 ± 0.05V
Note : Perform "3. Bright Adjustment" and "4. Contrast
Adjustment" alternately until each specified value is
satisfied.
Adjusting method:
1) Set page: 0, address: 01, data: 01.
2) Change the data of page: D, address: 52, and set the voltage
(A) between the reversed waveform pedestal and non-reversed
waveform pedestal to the specified value.
3) Press the PAUSE button of the adjusting remote commander.
4) Set the same data as page: D, address: 52 to page: D, address:
5D, and press the PAUSE button of the adjusting remote
commander.
5) Set page: 0, address: 01, data: 00.
6) Check that the specified value of "Contrast Adjustment" is
satisfied, if not, perform "Contrast Adjustment".
A
Pedestal
Fig. 5-3-29.
Pedestal
2H

5. Contrast Adjustment (VC-197 baord)

Set the level of the VIDEO signal for driving the LCD to the specified
value. If deviated, the screen image will be blackish or saturated
(whitish).
Mode
Signal
Measurement point
Measuring instrument
Adjustment page
Adjustment address
Specified value
Note : Perform "3. Bright Adjustment" and "4. Contrast
Adjustment" alternately until each specified value is
satisfied.
Adjusting method:
1) Set page: 0, address: 01, data: 01.
2) Change the data of page: D, address: 57, and set the voltage
(A) between the pedestal (0 IRE) and 100 IRE to the specified
value.
3) Press the PAUSE button of the adjusting remote commander.
4) Set page: 0, address: 01, data: 00 .
5) Check that the specified value of "Bright Adjustment" is
satisfied, if not, perform "Bright Adjustment".
A
0 IRE
5-41
VTR stop
10-step stair-step signal
Pin 2 of CN802 (VG) of VC-197
board
Oscilloscope
D
57
A = 3.30 ± 0.05V
100 IRE
2H
Fig. 5-3-30.