Sharp C-1020G Serviceanleitung Seite 6

SERVICE ADJUSTMENT
WHITE BALANCE ADJUSTMENT
The purpose of this procedure is to optimize the picture
tube to obtain good black and white picture at all brightness
levels while at the same time achieving maximum usable
brightness. Normal RF AGC setting and purity adjustments
must procede this procedure
This adjustment is to be made only after a warm-up
operation is provided for 5 minutes at least.
With antenna connected to the receiver, tune in picture
on a strong channel.
will not produce a color picture while the following
adjustments are being performed.
1. Set the Green Drive (R833) and Blue Drive (R837)
controls to mid-position.
2. Connect a short clip lead between TP402 and TP403.
7. Set the contrast control (R428) and Bright (R425) to
maximum.
8. Set the two Drive controls(R833, R837)to. obtain best
white uniformity on the picture tube screen.
9. Rotate the Contrast control (R428) to clockwise until a
dim raster is obtained. ,
10, Touch-up adjustment of the three Bias Controls to obtain
'best white uniformity on the picture tube screen.
BEAM CURRENT ADJUSTMENT (SUB CONTRAST)
Black and white tracking procedure must have been com-
pleted before attempting this adjustment.
with antenna connected to the receiver, tune in picture
on a strong channei.
1. Connect voltmeter porisitve probe to both ends of
R629.
2. Rotate Brightness and Contrast controls to maximum.
3. Adjust sub contrast control (R411) to obtain a reading
of 475yuA.
CHASSIS REMOVAL :
1. Remove the six screws from the back cover, and take the
cover out.
2. Pull out the contrast, color, brightness and tuning
knobs, remove the three screws and detach the tuner
IF unit.
3. Pull out the tone, volume and tuning knobs, remove
the four screws and detach the radio/cassette. unit.
4. Remove the one screw from the power transformer,
and detach the transformer.
5. Draw the TV chassis out.
PICTURE TUBE ASSEMBLY REMOVAL AND REPLACE
MENT
1. Remove PWB-A chassis from cabinet.
(Refer to CHASSIS REMOVAL procedure)
2. Disconnect. picture coating earth tip from the PWB-D.
3. Unplug picture tube socket board (PWB-D) from picture
tube.
4. Spread a heavy pad on blanket on the work surface to be
used to prevent scratching the cabient and carefully place
cabinet face down on this protective covering.
5. Remove the four screws that secure the picture tube
mounting tubs to the cabinet front.
6. Carefully grasp the picture tube assembly by its mounting
tubs and lift from the cabinet front.
The picture tube must be handled with care.
7. Remove the picture tube dag ground harness assembly.
8. Pull out the four plastic retainers from picture tube
mounting tabs.
9. Carefully seat the new picture tube assembly in place on
the cabinet front and install all hardware in reverse other
sequence.