Rf Agc Adjustment; White Balance Adjustment; Screen Adjustment - Sharp 20MR10 Service Manual

SER VICE ADJUSTMENT

RF AGC Adjustment

1. Receive a good local channel.
2. Enter the service mode signal category and select
the service adjustment "S01".
3. Set the data value to point where no noise or beat
appears.
4. Select another channel to confirm that no noise or
beat appears.
Note: You have to exit the service mode first to
select another channel.
V ideo Level (TV Det Video Level)
Adjustment
1. Receive a good local channel.
2. Enter the service mode signal category and select
the service adjustment "S02".
3. Set the data value to "02" first, then adjust the data
in ranges 02 ±2 step to obtain a normal contrast level.

Screen Adjustment

1. Connect to oscilloscope probe between TP855 and
ground of the CR T unit.
2. Receive a good local channel.
3. Enter the service mode Signal category and set the
service adjustment "S04" to step 30. Then select the
service adjustment "S12" and set the data value to
"00" to set the color level to the minimum level.
(record the original data first). You may skip this step,
if you selected a B/W picture or monoscope pattern.
Set also the "S05/S06/S07" data to minimum level.
4. Select the service adjustment "S03" and set the data
value to "01" to turn off the luminance signal (Y-mute).
5. Select the service adjustment "S13" and adjust the
data value to obtain 2.35 volts as shown in Figure B.
6. Adjust the master screen control until the raster
darkens to the point where raster is barely seen.
7. Adjust the service adjustment "S05" red, "S06" green
and "S07" blue to obtain a good grey scale with
normal white at low brightness level.
8. Select the service a adjustment "S03" and reset data
to "00". Select the service adjustment "S12" and reset
data to obtain normal color level.
9. Remove probe and reset the master screen control
to obtain normal brightness range.
2.35 Vdc
Figure B: WAVEFORM FOR SCREEN ADJUSTMENT

White Balance Adjustment

1. Receive a good local channel.
2. Select the service adjustment "S12" and set the data
3. Alternately adjust the service adjustment data of
4. Select the service adjustment "S12" and reset data
Sub-Picture Adjustment
1. Receive a good local channel.
2. Make sure the customer picture control is set to
3. Enter the service mode and select the service
4. Adjust the data value to achieve normal contrast
Sub-Tint Adjustment
1. Receive a good local channel.
2. Set the customer tint control to the center of it's range.
3. Enter the service mode and select the service
4. Adjust "S11" data value to obtain normal fresh tones.
Sub-Color Adjustment
1. Receive a good local channel.
2. Make sure the customer color control is set to center
3. Enter the service mode and select the service
4. Adjust "S12" data value to obtain normal color level.
Adjustment
1. Receive a good local channel.
2. Make sure the customer brightness control is set to
3. Enter the service mode and select the service
4. Adjust "S13" data value to obtain normal brightness
GND
9
value to "00" to set the color level to the minimun.
You may skip this step, if you selected a B/W picture
or monoscope.
"S08" and "S09" until a good grey scale with normal
white is obtained.
to obtain normal color level.
maximum.
adjustment "S10".
range.
adjustment "S11".
position.
adjustment "S12".
Sub-Brightness
center position.
adjustment "S13".
level.
20MR10