Sony GDM-20SHT Service Manual page 17

GDM-20SHT
• Landing Fine Adjustment
1. Place the set in the Helmholtz coil.
2. Enter a green signal only, and adjust the contrast to the maxi-
mum.
3. Attach a wobbling coil to the specified position of CRT
neck.
4. Attach a landing adjuster sensor on the CRT.
5. Using a landing checker, adjust the DY position, purity, tilt
of DY, and landing at the center and four comers.
6. Remove the landing adjuster sensor.
7. Swing up and down the DY so that the top and bottom pins
are equal. Also, swing left and right the DY so as to attain the
best horizontal trapezoid, and insert wedges in the form of
reverse "Y" to secure the DY.
8. Attach a landing adjuster sensor on the CRT.
9. Confirm the landing at each comer. and if out of specifica-
tion, stick a disk magnet to the funnel section. and perform
adjustment.
10. Change over the input signal to R, G, B and confirm that the
purity of monocolor is good.
11. Confirm that the DY is not tilted, then fix the purity magnet
with a white pen.
• Convergence Fine Adjustment
1. Enter the white crosshatch signal of the mode 3.
2. Confirm that the V -ST AT and H-STAT for the user control
are in the center.
3. Adjusting the RV -2 (H-STAT VR) on the board A, make
red, green, and blue lines parallel (vertical lines). Through
the bus adjustment, adjust the V -STAT to make red, green,
and blue lines parallel (horizontal line).
4. Adjust the magnet ring (hexode) at the rear of NTC so that
the distance between red and green, and the distance be-
tween blue and green of three color lines are equal. If the
compensation is deficient. adjust additionally the magnet
ring at the rear of DY.
5. Returning the H-ST AT VR and the V -ST AT bus control ad-
justed in step 3, eliminate a misconvergence in the center of
creen.
6. Fine adjustment of convergence
1) Adjust the XBV misconvergence with the XBV reactor.
2) Adjust the XCV misconvergence with the XCV reactor.
3) Adjust the Vertical misconvergence with the TVL.
4) Confirm the convergence of entire screen.
5) Fix the XBV, XCV, hexode, and H-STAT VR with a
white pen.
RGB
XCV Misconvergence
B R
><
--~f:---
R
- - - - G
--~ \ - - - B
I I
• Digital Convergence Fine Adjustment
1. Enter the white crosshatch signal of the mode 3.
2. Connect only the Rand B signals.
3. Adjustment of NTC (bus adjustment)
1)
Adjust the center convergence of screen with the
V-STAT.
2) Adjust the bottom convergence of screen with the NTC
BOTTOM.
3) Adjust the top convergence of screen with the NTC
TOP.
4. H-CONV. adjustment (bus adjustment)
1) Set the bus data H-STAT to 148 (94h), and adjust the H-
ST A T with the H-ST AT VR on the board A.
2) Adjust the convergence at the position as shown in the
order of numbers.
3) The H-STAT, if finely adjusted again, should be in the
range of 120 to 168.
4) Save the data.
5) Although the adjustment is executed for the signals
other than mode 3, the factory area for V -STAT and H-
ST AT is common to all modes, and therefore, do not
change the V -ST AT and H-STA T after they are adjusted
in the mode 3.
6) Copy the bus data of mode 3 to all modes.
7) Execute adjustment in all modes in the same manner as
that in 4-2).
8) After the adjustment is over, save the data.
9) If out of specification 0.24 mm or less, adjust using a
sheet of permalloy. (Replace the DY, if more than five
sheets are required.)
B
Prime mode 0.24 mm
A
Others 0.24 mm
B
Prime mode 0.24 mm
Others 0.28 mm
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