Sharp 14VT10X1, Service Manual

Page: 41 / 138

ADJUSTMENT
CRT cut-off and Sub-Brightness adjustment
l R853: R- bias control
l R859: G- bias control
l R865: B- bias control
l R857: G-drive control
l R863: B- drive control
Note:
1.
2
3.
4.
5.
6.
7.
8.
9.
Prior to this adjustment, warm up the unit with
6. Adjust the drive-control R863) so that the
the beam current of more than for more
colour temperature is at 7500°K. (High beam:
than 30 minutes
Receive “MONOSCOPE PATTERN” signal with
pattern generator.
Set R857 (G-driver control) at CENTER
position
Set R863 (B-driver
at CENTER
position.
Set R853
at position.
Set (G-bias control) at position.
Set R865 (B-bias control) at position.
Set the control at the “Normal” position that
contrast is Max
colour is center 5)
and brightness is center using control,
keys.
Set the screen control at (O/l 0) position.
Turn on (service switch) at the horizontal
position.
C o n n e c t t h e o s c i l l o s c o p e t o T P 8 5 2 ( R e d
cathode).
Adjust the sub-brightness control (R425) so that
the blanking pulse on
is 10 1
7. Adjust the contrast control and brightness
control so that the beam current is about
and check that the colour temperature
is at 7500°K. If the temperature is not at
go back to “CRT cut-off adjustment” and repeat
the adjustment.
0.310)
Sub-contrast control: R436
Note:
, ,
Slowly turn the screen control clockwise and
it where the horizontal raster appears
slightly, in one of the three
Carefully adjust the vias controls of the other
two
until the horizontal raster becomes
white.
1.
2.
3.
4.
5.
Prior to this adjustment, warm up the unit
with the beam current of more than
for more than 30 minutes.
Receive “MONOSCOPE PATTERN” signal with
pattern generator.
Set the Contrast controls at MAX position.
Set the brightness control at MAX
Connect beam ammeter to TP601
and
TP602 (Full scale: 3mA)
Adjust R436 so that the beam current becomes
PAL adjustment
Note:
Before this adjustment, the
adjustment must have been completed.
l R806: 1 H-delay amp control
l H-delay phase control
Receive “PAL COLOUR BAR” signal with
bar generator.
Connect the following resistance matrix to
pins and of the connector to which
an oscilloscope is connected.
the screen control counterclockwise until
the horizontal rester disappears, and stop it.
White balance/Back ground
R857: G-drive control
R863: B-drive control
l R436: Sub-Contrast control
Note:
Prior to this adjustment, warm up the unit
with the beam current of more than
for more than 30 minutes.
1. Receive “MONOSCOPE PATTERN” signal with
pattern generator.
2. Set the Contrast control and MAX position.
3. Set the brightness control at MAX position.
4. Connect beam ammeter to TP601 and TP602.
(Full scale: 3mA)
5. Adjust the sub-contrast control (R436) so that
the beam current becomes approx.
(rough adjustment).
1.
2.
( p i n o f
K )
Resistance Matrix
43