Screen Adjustment - Sharp 51GT-25S Service Manual

51GT-25S
PIF/AGC Adjustment
1. AFT Adjustment
AFT must be adjusted to a fixed value of 40.
2. RF-AGC Cut-In Adjustment (I2C BUS)
. Receive the «COLOUR BAR» signal (Channel E-
1
12). Signal strength: 57 dB V.
.
2 Enter into Service Mode.
.
3
Push CH until AGC appears on screen.
. Push key of R/C.Setting is made
4
automatically. During this setting the colour bar
shall go from red to yellow. When setting is
finished, colour bar disappears and B-STOP
(bus stop)is shown on screen.
.
Switch set OFF and ON again, setting is now
5
memorized.
GEOMETRY ADJUSTMENT PROCEDURE
1. HOR SHIFT
a) Receive Philips pattern signal.
b) When
c) When
d) Adjust the horizontal location to obtain picture centering (Fig.1).
2. VERT SHIFT
a) Receive Philips pattern signal.
b) When
c) When
d) Adjust the vertical location to obtain picture centering (Fig.2).
3. VERT AM
a) Receive Philips pattern signal.
b) When
c) When
d) Adjust the vertical size to obtain picture overscan (Fig.3).
4. VERT SLOP
a) Receive Philips pattern signal.
b) When button is pressed, upper picture scanning decreases and
lower picture scanning increases.
c) When
lower picture scanning decreases.
d) Adjust the vertical symmetry to obtain symmetrical scanning between
upper and lower picture (Fig.4).
button is pressed, picture moves to the left.
button is pressed, picture moves to the right.
button is pressed, picture moves up.
button is pressed, picture moves down.
button is pressed, vertical size of picture increases.
button is pressed, vertical size of picture decreases.
button is pressed, upper picture scanning increases and

Screen Adjustment

3. Focus Adjustment
1.
Apply mains voltage of 220V AC/50HZ to TV.
.
Receive Philips pattern signal to a level between
2
60 and 80 dB V.
.
3
Set contrast to 10/10, brightness to 5/10 and
colour 0/10.
.
Adjust focus potentiometer to obtain
4
maximum definition.
4. G2 Adjustment
1.
Apply mains voltage of 220V AC/50HZ to TV.
.
2 Receive the «MONOSCOPE» pattern signal to a
level between 60 and 80 dB V.
.
3
Enter into Service Mode. Press the TEXT key of
R/C and set to level.
.
4
Set to the point where the raster disappears on
the screen VR of FBT.
.
5
Check BKGD. If it is necessary adjust BKGD
according to instructions detailed in the next
page.
10
Fig. 1
Fig. 2
Fig. 3
Fig. 4