Sharp 28JS-74E Service Manual page 10

28JS-74E
Vertical Bow
Adjust the Vertical Bow so that the picture is centred.
The effect of this adjustment is shown in figure 11.
• When the volume up button is pressed, the vertical bow changes to left.
• When the volume down button is pressed, the vertical bow changes to right.
• Press the stand-by button on the remote control to store.
Vertical Amplitude
Adjust the Vertical Amplitude so that 8% over-scan is achieved.
The effect of this adjustment is shown in figure 12.
• When the volume up button is pressed, the vertical size of the picture increases.
• When the volume down button is pressed, the vertical size of the picture decreases.
• Press the stand-by button on the remote control to store.
S Correction
Adjust the S Correction so that the picture symmetrical between the top, centre and bottom.
The effect of this adjustment is shown in figure 13.
• When the volume up button is pressed, the top and bottom scanning decreases and the
centre scanning increases.
• When the volume down button is pressed the top and bottom scanning increases and the
centre scanning decreases.
• Press the stand-by button on the remote control to store.
Vertical Shift
Adjust the Vertical Shift so that the picture is centred.
The effect of this adjustment is shown in figure 14.
• When the volume up button is pressed, the picture moves up.
• When the volume down button is pressed, the picture moves down.
• Press the stand-by button on the remote control to store.
Colour Adjustments
The following adjustments should only be carried out when the CRT or IC801 are replaced.
G2, Cut Off and Gain Adjustments
1. Follow the procedure below to set the G2
1.1 Tune the set to the output of a signal generator (cross hatch pattern).
1.2 In the user menu, set contrast to 80/100 and brightness to 40/100.
1.3 Connect the oscilloscope to the TP1801 and adjust G2 to read 135V on the sensor pulse as in the drawing:
135 V
CH1 gnd
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Figure 11
Figure 12
Figure 13
Figure 14