Sharp LC-20B4M Service Manual download pdf (Page 13)

LC-20B4M

5. Adjustment

5-1. +B adjustment (R3714 Variable resistor)

1) Receive the colour bar signal.

2) Adjust the voltage at pin (4) of P3701 to 5.00 ± 0.02 V.

Note: The 5.0 V level is used as reference for all the line voltages. Make this adjustment as precisely as

possible.

5-2. Counter bias adjustment: COM BIAS on page 2

Adjust the "COM BIAS" setting until the contrast gets optimum (the black portion blackest). The adjustment

guideline is around 98.

5-3. TAMP adjustment

1) Feed the colour bar pattern signal.

2) See if the "Y" reading on adjustment process page 2 is within the range shown below. If not, adjust the

"NTSC TAMP" setting to bring the "Y" reading within the specified range.

3) If the "NTSC TAMP" setting has been readjusted, write down its new setting in the "PAL TAMP" and

"SECAM TAMP" items manually.

Model LC20B4M

Adjustment value 187~202

0 1 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

COM B I AS

TAMP L 817

YD TA

918

TAMP

022

NTSC TAMP

TAMP

PAL TAMP 26

SECAM

Y Data

(White 75%)

(Page 2 of adjustment process OSD)

5-4. White balance adjustment

1) Feed the monoscope pattern signal.

2) Adjust the "RCUTOFF" and "BCUTOFF" settings on adjustment process page 3 to achieve the color at the

same level as with the standard set.

1 2 ... 8 9 10 11 12 13 14 15 16 17 18 ... 81 82

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Sharp LC-20B4M Service Manual Page 13