Sharp LC 20M4U, Service Manual

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11
LC-20M4U
1-3. Counter bias adjustment
Keep off the video input signal.
Place the specified tool at the center of the screen.
Observe the output of the tool on the oscilloscope screen.
Adjust the “COM BIAS” setting on the adjustment process page 2 so that the peak-to-peak level of the waveform
should be minimum.
1-4. White balance adjustment
Feed the NTSC monoscope pattern signal.
Adjust the “RCUTOFF” and “BCUTOFF” settings on the adjustment process page 2 so as to obtain the color of the
same level as the standard monitor.
Note: For the “RCUTOFF” and “BCUTOFF” settings, keep the readings in the range of -9 to +9. If out of this range, the
user-adjustable range is reduced.
Adjust them in the indication value range of -9, -7, -5, -3, -1, +1, +3, +5, +7, +9 (odd numbers). When it becomes
even-numbered value (include 0), side favor noise sometimes occurs in the monochrome signal of the specific
gradation.
Do not change the “GCUTOFF” settings (It also change the black level).
1-5. Factory setting
Set the product’s input mode, picture quality and other factors to their factory setting.
There are the following two ways.
●
With the keys of the set
In the inspection process mode, hold down both the “SELECT(
▲
)” and “VOL (+)” buttons of the set until “SETTING
COMPLETE” appears on the screen.
Note: Be careful not to turn off the power, release the above two keys and press any other keys until “SETTING
COMPLETE” appears on the screen.
●
With the adjustment remote controller
With the adjustment remote controller, make the factory settings. Either of the following remote controllers codes
will do.
Calling the Inspection process mode
There are the following two ways.
●
With the keys of the set
Hold down the “MENU” and “AV INPUT” buttons of the set and turn on the power.
●
With the adjustment remote controller
Use the inspection process key.
Key name Remote controller code
Factory setting 100000111111110
Factory setting 100000001010110
E
Changing on-screen display
K
Inspection process mode Factory setting Setting complete
SETTING COMPLETE
→
→
E