Sharp 21HT-15 (serv.man8) Service Manual ▷ View online
9
21HT-15H
•
SCREEN ADJUSTMENT
1. G2 Adjustment
1. Apply mains voltage of 220V ac / 50Hz to TV.
2. Go into service mode (refer to “How to access service mode” section).
3. Use
CH
/
CH
buttons in order to select «BLUE-BACK: 1».
4.
Use the volume down button (
) to deactivate the blue-back feature. «BLUE-
BACK: 0» will appear on screen.
5.
Re-start the TV set with the mains switch button (
) to store the adjustment
and exit service mode.
6. Normalise the picture control settings (
contrast, colour, brightness...)
7. Press TV/VIDEO button in order to select «SCART» (without video signal: black
screen).
8. Apply the oscilloscope test probe to the test point <TP851> (Red output of
IC801) to see the signal shown in Fig.4.
9. Adjust SCREEN VR (G2) to obtain 3 Vdc ± 0.1 Vdc.
10. Go into service mode (refer to “How to access service mode” section).
11. Use
CH
/
CH
buttons in order to select «BLUE-BACK: 0».
12. Use the volume up button (
) to deactivate the blue-back feature. «BLUE-BACK: 1» will appear on screen.
13. Re-set the TV with the mains switch button (
) to store the adjustment and exit service mode.
2. Focus 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
µ
V.
3. Normalise the picture control settings (
contrast, colour, brightness...)
4. Adjust focus potentiometer to obtain maximum definition.
•
AGC ADJUSTMENT
1. Receive the «COLOUR BAR» signal (Channel E-
12).
Signal
Strength: 57 dB
µ
V ± 1 dB µV (50 ohm open) or 59 dB
µV ± 1 dB µV (75 ohm open).
2. Connect the oscilloscope to test point <TP201> (R201
lead) and the voltmeter c.c., as shown in Fig.5.
3. Go into service mode (refer to “How to access service
mode” section).
4. Use
CH
/
CH
buttons in order to select «AGC».
5. Use
/
to obtain the Tuner output pin drop: 0.1 V ~
0.3 V below maximum voltage.
6. Change the antenna input signal to 66-70dB µV, and
make sure there is no noise.
7. Turn up the input signal to 90-95 dB µV to be sure that
there is no cross.
8. Re-set the TV with the mains switch button (
) to store the adjustment and exit service mode.
1V
3.0 ± 0.1 Vdc
0 V
0.1V
OSCILLOSCOPE
VOLTMETER
4.5V
TP201
TV SET
Fig.4
Fig.5
10
21HT-15H
••••
GEOMETRY ADJUSTMENT PROCEDURE
1. Receive Philips.
2. Go into service mode (refer to “How to access service mode” section).
3. Use
CH
/
CH
buttons in order to select the required adjust.
4.
Re-set the TV with the mains switch button (
) to store the adjustment and exit service mode.
V-LIN (Vertical slope adjust)
a) Use
/
buttons to move the picture.
b) Adjust the vertical linearity to obtain picture centring (fig. 6).
V-AMP (Vertical amplitude adjust)
a)
When
button is pressed, vertical size of picture increases.
b)
When
button is pressed, vertical size of picture decreases
c) Adjust the vertical amplitude to obtain picture overscan (Fig. 7).
V-CENT (Vertical shift adjust)
a) When
button is pressed, picture moves down.
b)
When
button is pressed, picture moves up.
c)
Adjust the vertical shift to obtain picture centring (Fig. 8).
H-CENT (Horizontal shift adjust)
d) When
button is pressed, picture moves to right.
e)
When
button is pressed, picture moves to left.
f)
Adjust the vertical shift to obtain picture centring (Fig. 9).
Fig. 6
Fig. 7
Fig. 8
Fig. 9
11
21HT-15H
•
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.
•
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:
MODEL
X
Y Screen
temperature
21HT-15H
0.290
±
0.015
0.284
±
0.015
8900º K-20 MPCD
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 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:
MODEL
X
Y Screen
temperature
21HT-15H
0.290
±
0.015
0.284
±
0.015
8900º K-20 MPCD
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 obtain the
above values.
12
21HT-15H
CHASSIS LAYOUT
MOTHER UNIT
CRT UNIT
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