Sharp 21HS-50 (serv.man2) Service Manual ▷ View online
9
21HS-50H
•
SCREEN ADJUSTMENT
1. G2 Adjustment
1.
Enter the service mode (see page 6).
2.
Use the channel up or channel down buttons to enter the << BLUE-BACK >>
function.
function.
3.
Set this to << BLUE-BACK: 0 >>, i.e. blue background is turned off.
4.
Turn the set off at the mains.
5.
Turn the set back on.
6.
Set the picture control settings to normal.
7.
Select the SCART input by pressing the TV/SCART button on the remote con-
trol. Do not connect an input to the SCART socket. A blank raster will appear.
trol. Do not connect an input to the SCART socket. A blank raster will appear.
8.
Connect an oscilloscope to TP851 on the CRT PWB. The waveform as in figu-
re 4 should be displayed.
re 4 should be displayed.
9.
Adjust the G2 control (screen voltage) so that the peak of this waveform is 3.0V
+/-0.1V above the zero volt line.
+/-0.1V above the zero volt line.
10. Enter the service mode.
11. Turn the blue background function back on again - set << BLUUE-BACK: 1 >>.
12. Turn off the receiver using the mains button.
13. The G2 adjustment is now complete.
2. Focus Adjustment
1.
Receive a monoscope pattern signal at a level of 60 to 80 dBuV.
2.
Set the picture settings to normal.
3.
Adjust the focus potentiometer to obtain maximum definition.
•
AGC ADJUSTMENT
1.
Tune the receiver into a colour bar signal on channel E-12.
2.
Set the RF generator to an output signal strength of 57dBuV (+/-1dBuV) –50 Ohms unbalanced.
3.
Connect an oscilloscope to TP201. TP201 is one end of R201.
4.
Enter the service mode (see page 6).
5.
Use the channel up and channel down buttons to enter the AGC mode.
6.
By using the volume up and the volume down buttons, adjust the AGC until the voltage on TP201 drops by 0.1V
to 0.3V below its maximum value.
to 0.3V below its maximum value.
7.
Change the input signal strength to 66-70dBuV and make sure that there is no noise apparent in the picture.
8.
Turn the receiver off at the mains, this will exit the service mode and store the adjustment.
9
9GF
9
Fig. 4
10
21HS-50H
•
GEOMETRY ADJUSTMENT PROCEDURE
To adjust the geometry, follow the procedure outlined below:
1.Tune the set into a Philips test pattern.
2.Enter the service mode as described on page 6.
3.Use the channel up or channel down buttons to enter the desired mode
4.Use the volume buttons to achieve correct setting.
5.When adjustments are complete, use the standby button to turn off the set. The adjustment values will be stored
at this point.
V-LIN
Adjust the vertical linearity control so that the picture centring is as shown in figure 5.
Adjust the vertical linearity control so that the picture centring is as shown in figure 5.
V-AMP
Adjust the vertical amplitude control so that the picture overscans as shown in figure 6.
Adjust the vertical amplitude control so that the picture overscans as shown in figure 6.
V-CENT
Adjust the vertical centring control so that the picture is centred as shown in figure 7.
Adjust the vertical centring control so that the picture is centred as shown in figure 7.
H-CENT
Adjust the horizontal centring control so that the picture is centred as shown in figure 8.
Adjust the horizontal centring control so that the picture is centred as shown in figure 8.
Fig. 5
Fig. 6
Fig. 7
Fig. 8
11
21HS-50H
•
COLOUR ADJUSTMENT PROCEDURE
The following adjustments should only be carried out when the CRT or IC801 are replaced.
NOTES:
•
This adjustment must be done after warming up the unit for 30 minutes or longer with a beam current over 700
µA.
µA.
•
The red value «DRI-RS» should be fixed to 42. (Refer to “How to access service mode” section).
•
«DRI-GS» adjustment alters “Y” co-ordinate.
•
«DRI-BS» adjustment alters “X” and “Y” co-ordinates.
ADJUSTMENT METHOD 1 (using the signal generator, varying the picture signal)
1. Adjust G2.
2. Input a white pattern with burst signal from SCART.
3. Position the colorimeter in the centre of screen.
4. Adjusting input signal level, select a luminance of 70 nits.
5. Operate again in “service mode“ and select «DRI-GS» and/or «DRI-BS» locations to obtain colour co-ordinates:
2. Input a white pattern with burst signal from SCART.
3. Position the colorimeter in the centre of screen.
4. Adjusting input signal level, select a luminance of 70 nits.
5. Operate again in “service mode“ and select «DRI-GS» and/or «DRI-BS» locations to obtain colour co-ordinates:
6. Re-set the TV with the mains switch button to store the adjustment and exit service mode.
7. Check colour co-ordinates “X” and “Y” at 20 a 120 Nits. It may be necessary to repeat the same procedure to
7. Check colour co-ordinates “X” and “Y” at 20 a 120 Nits. It may be necessary to repeat the same procedure to
obtain the above values.
ADJUSTMENT METHOD 2 (using the signal generator, with a fixed picture signal)
1. Adjust G2.
2. Tune a white pattern with burst signal.
3. Operate in “service mode”:
4. Using «SUB-CON», select a luminance of 70 nits.
5. Operate again in “service mode“ and select «DRI-GS» and/or «DRI-BS» locations to obtain colour co-ordinates:
2. Tune a white pattern with burst signal.
3. Operate in “service mode”:
4. Using «SUB-CON», select a luminance of 70 nits.
5. Operate again in “service mode“ and select «DRI-GS» and/or «DRI-BS» locations to obtain colour co-ordinates:
6. Select «SUB-CON». Return data to “63”.
7. Re-set the TV with the mains switch button to store the adjustment and exit service mode.
8. Check colour co-ordinates “X” and “Y” at 20 a 120 Nits. It may be necessary to repeat the same procedure to
7. Re-set the TV with the mains switch button to store the adjustment and exit service mode.
8. Check colour co-ordinates “X” and “Y” at 20 a 120 Nits. It may be necessary to repeat the same procedure to
obtain the above values.
X
Y
Screen temperature
0.290
±
0.015
0.284
±
0.015
8900º K-20 MPCD
X
Y
Screen temperature
0.290
±
0.015
0.284
±
0.015
8900º K-20 MPCD
12
21HS-50H
CHASSIS LAYOUT
MOTHER UNIT
CRT UNIT
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