SHARP LC20A2M
Service Manual

LC-20A2M
4. Getting Initialized 4-1. Connect pins (81) and (82) of IC2001 to GND. Turn on the power. 4-2. Select the model number (A2H). 4-3. Select the screen size (20 inches). 5. Adjustments 5-1. +B adjustment (+B ADJ. on page 1) 1) Receive the colour bar signal. 2) Adjust the voltage at pin (8) of P303 to 5.00 ±0.02 V. Note: The 5.00 V level is used as reference to the supply voltage. Make an exact adjustment to 5.00 V. 5-2. Counter bias adjustment ...... �COM BIAS� on page 2 1) Receive the monoscope pattern signal. 2) Adjust the �COM BIAS� setting so that the contrast at the staircase wave is maximum. 5-3. TAMP adjustment 1) Receive the colour bar signal. 2) See if the �Y� reading on page 2 of the adjustment process is somewhere between BB and CA. If not, make the �NTSC TAMP� adjustment to get the �Y� reading in the range of BB thru CA. 3) Then enter the above setting, if made in the �NTSC TAMP� adjustment, in the following items in the manual mode. �PAL TAMP�, �SECAM TAMP�, �PAL-M TAMP� and �PAL-N TAMP�.

(Adjustment process menu on-screen display on page 2)
0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 Y data (75% white) 1 2 COM NTSC PAL PAL PAL TV SECAM -M H N B I AS 1 1 1 2 2 2 2 NG 7 9 7 7 7 7 4 0 0 0 R3 Y 0 0 0 0 0 0 0 0 0 0 B5 TAMP TAMP TAMP TAMP TAMP PEAK I 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26

RCUTOFF GCUTOFF BCUTOFF G3 G1 B3 B4

5-4. White balance adjustment 1) Receive the monoscope pattern signal. 2) Adjust so that the �RCUTOFF� and �BCUTOFF� settings on page 2 of the adjustment process are optimum. Note: The �RCUTOFF� and �BCUTOFF� settings in the adjustment process should be in the range of -10 thru +10. If without this range, the variable user control range will be reduced.

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