Sharp 20LK32, Service Manual

Page: 11 / 35

11
20LK32
20LK62
Ë
SERVICE ADJUSTMENT
RF AGC Adjustment
1. Receive a good local channel.
2. Enter the service mode signal category and select
the service adjustment "AGC".
3. Set the data value to point where no noise or beat
appears.
4. Select another channel to confirm that no noise or
beat appears.
HORIZONTAL AND VERTICAL DEFLECTION LOOP ADJUSTMENT
No. Adjusting point Adjusting procedure/conditions Waveform and others
V-SLOPE(I
2
C
BUS CON-
TROL)
V-CENTER (I
2
C
BUS CON-
TROL)
V - AMP (I
2
C
BUS CON-
TROL)
S-CORREC-
TION (I
2
C BUS
CONTROL)
H - CENTER
1. Receive the "Monoscope Pattern" signal.
2. Call the "V-LIN" mode.
3. Increase or decrease "V-LIN" by Volume key till
the horizontal line in the center of monoscope is
just at the position where the blanking starts.
1. Call the "V-CENT" mode.
2. Increase or decrease "V-CENT" by Volume key till
the picture is centered.
1. Call the "V-AMP" mode.
2. Increase or decrease "V - AMP" by Volume key to
set overscan of 10.0% typical.
Adjustment Spec 10.0% range
±
1%.
FIXED DATA, NO NEED TO ADJUST.
1. Call the "H-CENT" mode.
2. Increase or decrease "H-CENT" by Volume key
to center the picture horizontal.
1
2
3
4
5
Focus
adjustment 1. Receive the "Monoscope Pattern" signal.
2. Press R/C to set Picture NORMAL condition.
3. Adjust the focus control to get the best focus. 6
No. Adjusting point Adjusting procedure/conditions Waveform and others
SUB-TINT (I
2
C
BUS CON-
TROL)
1. Receive the "Colour Bar" signal through AV in.
2. Connect the oscilloscope to TP853 (Pin (5) of
P882) BLUE-OUT.
»
Range : 100mV/div. (AC)(Use Probe 10:1)
»
Sweep time : 10 µsec/div.
3. Call the "SUB-TINT" mode in service mode. Ad-
just the "SUB-TINT" bus data to obtain the wave-
form shown as Fig 1.
4. "SUB-TINT" bus data decrease 4 steps to get fi-
nal waveform. (Fig 2.)
5. Clear the SERVICE mode.
1
CHROMA ADJUSTMENT
FINAL WAVEFORM
Fig 2
WAVEFORM 1
Y CY G MG R B W
SAME LEVEL
Fig 1