A Board Adjustments - Sony TRINITRON KV-20M20 Service Manual

5-2. A BOARD ADJUSTMENTS
RF AGC ADJUSTMENT (IF BLOCK VR)
1. Input a color-bar signal.
2. Adjust AGC VR of TU101 so that snow, noise, and cross-
modulation disappear from the picture.
3. Verify picture quality on each channel.
H. FREQUENCY ADJUSTMENT
1. Input a monoscope signal.
2. Set to Service adjustment Mode.
. Connect a frequency counter to base of Q550 (TP-86 H.
DRIVE)
4. Select the item of AFC, set to 3 level (free run).
5. Check H. frequency for the 15734 + 60 Hz.
6
7
WwW
. Select the item of AFC again, adjust the level "0".
. Write into the memory by pressing then .
V. FREQUENCY ADJUSTMENT
1. Select video 1 with no signal input.
2. Set the conditions with standard setting.
3. Connect a capacitor (10 uF) across pin @) of IC301
(V. SYNC) and ground.
4, Connect the frequency counter across CN501 VDY (+)
connector and ground.
. Check V. frequency for the 59 + 0.5 Hz
. Disconnect a capacitor form IC301.
1C 301 (41)
V-Sync
nw
4
T 10 pF
CHROMA TRAP ADJUSTMENT (CROM)
1. Input a red signal.
2. Set to Service adjustment Mode.
3. Connect an oscilloscope CN703 Pin@ (R OUT) of C board
ground.
. Select CROM with [I] and 4] .
. Adjust with [3] and [6] for the 0 level.
as
Element of sub-carrier
R-OUT |
4
— O level
;
-21-
6. Write into the memory by pressing then :
SUB CONTRAST ADJUSTMENT (SCON)
1, Input a color-bar signal.
2. Select the red color.
3. Set to Service adjustment Mode.
4. Set the conditions as follows.
PICTURE ........... MAX
COLOR ........... MIN
BRIGHT ........... CENTER
a0 Cerne ee oeea ON (1)
GON ....... 0... OFF (0)
BON ........... OFF (0)
1:ON
0: OFF
SERVICE RON 1
5. Connect an oscilloscope to CN703 Pin) (R OUT) of C
board and ground.
6. Select SCON with [I] and [4] .
7. Adjust with [3] and [6] for the 1.6 + 0.05 Vp-p.
White
1.6 £0.05 Vp-p.
8. Write the memory by pressing then [ENTER].
9. Return the following back to normal after adjustment.
PICTURE ........... MAX
COLOR ........... CENTER
BRIGHT ........... CENTER
RON ...seeeeeee ON (1)
GON "iehca Guay: ON (1)
BON cinereus ON (1)
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 with [3} and {6] for the bar center.
5. Write the memory by pressing then ;
6. Check if the text is displayed on the screen.
SERVICE AFC 0