Sharp LC-20A2M, Service Manual

Page: 13 / 40

13
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”.
0
1
2
3
4
5
6
7
8
9
10
11
12
13
0 1
2
2
C
N
P
S
P
P
T
R
G
B
G
G
3
O
T
A
E
A
A
V
C
C
C
3
1
4
M
S
L
C
L
L
U
U
U
5
C
A
-
-
H
T
T
T
6
B
T
M
M
N
-
O
O
O
B
B
7
I
T
A
P
F
F
F
3
4
8
A
A
M
T
T
T
E
F
F
F
9
S
M
P
A
A
A
A
10
P
M
M
M
K
R
11
P
P
P
I
3
Y
12
N
13
G
14 15 16
0
0
17
0
0
18 19 20
0
0
21
0
0
22 23
1
24
1
1
2
2
2
2
0
B
25
7
9
7
7
7
7
4
0
0
0
0
5
26
(Adjustment process menu on-screen display on page 2)
Y data (75% white)
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.