Mb Board Adjustments - Sony TRINITRON KV-25FS12 Service Manual

4-4. MB BOARD ADJUSTMENTS

H. FREQUENCY (FREE RUN) CHECK
1. Input a TV mode (RF) with no signal.
2. Connect a frequency counter to base of Q501
(TP-500 H. DRIVE) on the A Board.
3. Check H. Frequency for 15735 ± 200 Hz.
V. FREQUENCY (FREE RUN) CHECK
1. Select video 1 with no signal input.
2. Set the conditions for a standard setting.
3. Connect the frequency counter to TP-508 (V OUT) or CN501 pin 6
(V DY+) and ground on the A Board .
4. Check that V. Frequency shows 60 ± 4 Hz.
DRIVE (RDRV)
1. Input a color-bar signal and set the level to 75%.
2. Set in Standard mode.
3. Activate the Service Adjustment Mode.
4. Set both GON and BON items. Using 3 and 6 set each to the
following values. Leave RON set to "1".
Mode
service
Signal
Type
ntsc
vchp
R ON: ON (1)
G ON: OFF (0)
B ON: OFF (0)
5. Connect an oscilloscope probe to CB Board, J701 Pin 12 (KR) (Red
Out) .
6. Select RDRV with 1 and 4 .
7. Adjust the value of RDRV with 3 and 6 for
92.0 ± 2 VDC.
92.0 ± 2VDC
8. Reset GON and BON values to "1".
R ON: ON (1)
G ON: ON (1)
B ON: ON (1)
9. Press MUTING then ENTER to save into the memory.
Item
Display
Data
Category Item
video rdrv 26
00000000 00000000
DISPLAY POSITION ADJUSTMENT (DISP)
1. Input a color-bar signal.
2. Set to Service Adjustment Mode.
3. Select DISP with 1 and 4 .
4. Adjust values of DISP with 3 and 6 to adjust characters to the center.
5. Write to memory by pressing MUTING then ENTER .
6. Check to see if the text is displayed on the screen.
Signal
Type
SUB BRIGHT ADJUSTMENT (SBRT)
1. Input a monoscope signal.
2. Activate the Service Adjustment Mode.
3. Set the PICTURE and BRIGHTNESS to minimum.
4. Select the SBRT item with 1 and 4 .
5. Adjust the values of SBRT with 3 and 6 to obtain a faintly visible
crosshatch.
6. Press MUTING then ENTER to save into the memory.
SUB HUE, SUB COLOR ADJUSTMENT (SHUE,
SCOL)
1. Input a color-bar signal.
2. Activate the Service Adjustment Mode.
3. Connect an oscilloscope probe to CB Board, CN705 Pin 4 Blue Out.
4. Select the SHUE and SCOL item with 1 and 4 .
5. While showing the SHUE item, adjust the waveform with 1 and 4
until the second and third bars show the same level (V2 = V3 < 0.1
Vp-p).
6. While showing the SCOL item, adjust the waveform with 3 and 6
until the fi rst and fourth bars show the same level (V1 = V4 < 0.1
Vp-p).
7. Press MUTING then ENTER to save into the memory.
V. SIZE ADJUSTMENT (VSIZ)
1. Input a crosshatch signal.
2. Activate the Service Adjustment Mode.
3. Select the VSIZ item with 1 and 4 .
4. Adjust value of VPOS with 1 and 4 for the best vertical center.
5. Press MUTING then ENTER to save into the memory.
— 19 —
KV-25FS12 / 25FS12C
Display Item
Mode
Category Item Data
service micro disp 48
ntsc
vchp
00000000 00000000
8 8 8! 8"