Sharp VT-3448X, Service Manual

Page: 16 / 144

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CRT CUT-OFF, BACKGROUND AND SUB-CONTRAST ADJUSTMENT
1 CUT-OFF bus data adjustment)
Receive the monoscope pattern signal.
Put the set in the service mode and call up the DIRECT mode
Set the screen control to
position.
Press the “CONFIRM” key on the remote controller to reach the horizontal centering mode. (S-PICTURE key on
the set)
Turn the screen control clockwise until the horizontal raster of the first glimmering becomes slightly
visible.
Adjust the cut-off data of the other two until the horizontal raster becomes whitish.
Note : The data can be turned up and down with the above keys.
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CUT OFF UP
KEY
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G CUT OFF DOWN KEY
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CUT OFF DOWN KEY
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B CUT OFF UP KEY
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G CUT OFF UP KEY
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B CUT OFF DOWN KEY
Turn the screen control counterclockwise until the horizontal raster disappears.
Note : Before starting this adjustment, warm up the unit for minutes or longer at a beam current of over
(over for
Press the “CONFIRM” key on the remote controller to call up the NORMAL mode. (S-PICTURE key on the set)
SUB-BRIGHTNESS bus data adjustment)
Using the remote controller, call the SUB-BRIGHT setting mode (Receive the crosshatch and gray scale
signal.)
the sub-brightness data so that the third black portion to counted from the left of the screen) of the
window pattern looks sinking.
Note : The service mode adjustment in the above steps and should be carried out after the white
balance and background adjustments.
Exit from the service mode.
WHITE BALANCE AND BACKGROUND bus data adjustment)
Receive the (monoscope pattern) signal.
Put the set in the service mode and call up the DIRECT mode
Connect the beam ammeter between
and
Using the sub-contrast control, roughly adjust the beam current to about (about for
Adjust the G-drive and B-drive data to have a temperature of (white).
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x
y
(with a temperature meter
Note : The data can be turned up and down with the above keys.
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G-DRIVE UP KEY
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B-DRIVE UP
KEY
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G-DRIVE DOWN KEY
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B-DRIVE DOWN KEY
Adjust the contrast and brightness controls to have the beam current of or so. Now check the back-
ground If the temperature is not as specified, go back to No, 1 on the preceding page.
Exit from the service mode.
Note : Before starting this adjustment, warm up the unit for minutes or longer at a beam current of over
(over for