Set-Up Adjustments; Screen Voltage Adjustment; Screen (G2) Adjustment; Defl Ection Yoke Tilt Adjustment - Sony KP-43T90 Service Manual

2-1. SCREEN VOLTAGE ADJUSTMENT

(COARSE ADJUSTMENT)
1. Select a video input with no signal applied (the screen must be black,
and the room must be as dark as possible. You may use a heavy
blanket over the screen to block out ambient light).
2. Select picture mode "Personal 1" or "Personal 2", and set
BRIGHTNESS to 50% and PICTURE to minimum.
3. Turn the green SCREEN control on the focus block all the way to
the left and then gradually turn it to the right until the retrace line is
barely visible.
4. Gradually turn the control to the left until the retrace line just
disappears.
5. Repeat steps 1 through 4 for the red and blue CRTs.
R G
SCREEN
R G
FOCUS
FOCUS block

2-2.SCREEN (G2) ADJUSTMENT

(FINE ADJUSTMENT)
If the jig described below is available, it is recommended that the G2 Fine
Mode Adjustment be performed to set the screen controls to their optimal
condition. If desired, you can build the jig illustrated below, using 3-watt
resistors. Please note that if the proper voltage is not obtained with the
listed resistor's values, then increase or decrease one of the values in
the resistor network to obtain the correct voltage.
1. Select VIDEO-1 mode no signal applied (the screen must be black).
2. Connect the G2 JIG.
3. Switch on the JIG.
4. Connect an oscilloscope to the TP701(KR), TP732(KG) and
TP761(KB) of CR board, CG board and CB board.
5. Adjust red, green, and blue screen voltage to 168-172V with SCREEN
controls on the focus block, as shown below.
G2 JIG
3.3k
200V
170V +/- 2V
GND
SECTION 2: SET-UP ADJUSTMENTS
B
B
K
SW
5.6k 5.6k 5.6k
GND
pedestal level
2-3. DEFLECTION YOKE TILT ADJUSTMENT
1. Display a cross-hatch pattern
2. Enter the service mode.
3. Cover the red and blue CRT lenses with lens caps to allow only green
to show (or use the method shown in the note below for turning off the
CRTs individually without using lens caps).
4. Loosen the green CRT's defl ection yoke set screw and align the tilt
of the defl ection yoke so that the horizontal bars at the center of
the cross-hatch pattern are parallel to the top and bottom edges of
the screen.
5. After aligning the defl ection yoke fasten it securely, making sure it is
fully forward on the neck of the CRT.
6. The tilt of the defl ection yoke for red and blue are aligned the same
way as the green CRT.
Cover the green and blue CRT lenses with lens caps (or use the
method shown in the note below for turning off the CRTs individually
without using lens caps), then repeat steps 4 and 5 for the red CRT.
Cover the green and red CRT lenses with lens caps (or use the
method shown in the note below for turning off the CRTs individually
without using lens caps), then repeat steps 4 and 5 for the blue CRT.
Note: If lens caps are unavailable, you can cut off the unnecessary color
beams in the service mode by individually changing the data from "1"
to "0" in category VPNT, item 28 RON (red), item 29 GON (green), or
item 30 BON (blue).
2-pole magnet
— 13 —
KP- 43T90 / 48V90 / 53V90 / 61V90
4-pole magnet
Deflection yoke
Anode cap