Circuit Adjustments; Tv Input Sub Contrast Adjustment; Video Input Sub-Hue And Sub Color Adjustment; Component Input Sub-Hue And Sub-Color Adjustment - Sony RA-3B Service Manual

4-1.TV INPUT SUB CONTRAST ADJUSTMENT

(VPNT-SCON)
1. Display a color bar signal through the TV's VHF/UHF input.
2. Mode: Personal 1 or 2
PICTURE: maximum
BRIGHTNESS: center
3. Enter the service mode.
4. Turn off the blue and red CRTs by changing the data from "1" to "0"
in category VPNT item 28 RON (red), and item 30 BON (blue). If this
step is not followed, the ABL circuit may prevent you from adjusting
the peak-to-peak amplitude to 1.8 V.
5. Connect an oscilloscope between pin 7 of CN204 (A board) and
ground.
6. Select adjustment category "VPNT" adjustment item 19 "SCON", and
adjust using the 3 or 6 button on the remote so that the wave form
level is 1.80 ± 0.05Vp-p.
7. Press "MUTING" and then "ENTER" to save the adjustment data.
4-2.VIDEO INPUT SUB-HUE AND SUB-COLOR
ADJUSTMENT (VPNT-SHUE, SCOL)
1. Display a color bar signal through a video input.
2. Mode: Personal 1 or 2
PICTURE: maximum COLOR: center
BRIGHTNESS: center COLORTEMP: neutral
3. Enter the service mode.
4. Connect an oscilloscope between pin 5 of CN204 (A board) and
ground.
5. Alternately select adjustment category "VPNT" adjustment item #20
"SHUE" and item #21 "SCOL", and adjust them so that VB1 = VB4,
and VB2 = VB3 as shown below.
VB1
6. Add 2 to the adjusted value of "SCOL".
7.Press "MUTING" and then "ENTER" to save the adjustment data.
SECTION 3: CIRCUIT ADJUSTMENTS
COLOR: minimum
COLORTEMP: neutral
White
1.80 ± 0.05 Vp-p
Black
VB2 VB3 VB4
4-3.COMPONENT INPUT SUB-HUE AND SUB-
COLOR ADJUSTMENT (DAC-UVSH, UVSC)
1. Select VIDEO 4 and display a color bar signal.
2. Mode: Personal 1 or 2
PICTURE: maximum
BRIGHTNESS: center
3. Enter the service mode.
4. Connect an oscilloscope between pin 5 of CN204 (A board) and
ground.
5. Alternately select adjustment category "DAC", adjustment item # 0
"UVSH" and item #1 "UVSC" and adjust them so that VB1 = VB4 and
VB2 = VB3 as shown below.
6. Press "MUTING" and then "ENTER" to save the adjustment data.
4-4.PIP SUB CONTRAST ADJUSTMENT
(PYC-PSCN)
1. Display a color bar signal through the TV's VHF/UHF input.
2. Mode: Personal 1 or 2
PICTURE: maximum
BRIGHTNESS: center
3. Enter the service mode, and then select the PIP (Picture-in-Picture)
mode.
4. Select an unused video input for the main picture (it must be black),
and select the tuner for the small picture (it must be showing
colorbars).
5. Connect an oscilloscope between pin 7 of CN204 (A board) and
ground.
6. Select adjustment category "PYC", adjustment item # 0 "PSCN" and
adjust so that the peak-to-peak voltage is 1.65 ± 0.05Vp-p as shown
below.
7. Press "MUTING" and then "ENTER" to save the adjustment data.
— 27 —
KP- 43T90 / 48V90 / 53V90 / 61V90
COLOR: center
COLORTEMP: neutral
VB1
VB2 VB3 VB4
COLOR: minimum
COLORTEMP: neutral
White
1.65 ± 0.05