Sharp LC-20A2E (serv.man2) Service Manual ▷ View online
LC-20A2E
9
ADJUSTING PROCEDURE OF EACH SECTION
[1] Entering the MAIN side adjustment process mode
There are three methods below.
1) Press the “Adjustment process key” on the remote control after turning on the power.
2) Pressing both the MENU key and the TV/VIDEO key on the main body, turn on the power. Then, press the volume
1) Press the “Adjustment process key” on the remote control after turning on the power.
2) Pressing both the MENU key and the TV/VIDEO key on the main body, turn on the power. Then, press the volume
DOWN key and the tuning UP key at the same time.
3) Turn on the power with falling either KEY4 (pin 81 of microcomputer) or KEY5 (pin 82 of microcomputer) to “L”.
[Note] For the method 3), the ROM is initialized at the same time. Therefore, 3) must be executed if IC2004 or IC2001
[Note] For the method 3), the ROM is initialized at the same time. Therefore, 3) must be executed if IC2004 or IC2001
is changed. For 1) or 2), the main body only enters the MAIN side adjustment process.
[2] Entering the TUNER side adjustment process mode
4) Entering the TUNER side adjustment process
MENU key on the main body
→
Tuning UP key (remote control)
→
Select the position shown in the figure below and
press the M key (remote control) within 1 second.
→
Enters the adjustment process.
[3] Adjustment
MAIN side adjustment (Press the “M” key to move the cursor and press the volume UP/DOWN key to make an
adjustment.)
• Power supply voltage adjustment (+B 5V)
• Model setting
• Inch size setting
• COMMON BIAS adjustment of LCD module
• CUTOFF adjustment
adjustment.)
• Power supply voltage adjustment (+B 5V)
• Model setting
• Inch size setting
• COMMON BIAS adjustment of LCD module
• CUTOFF adjustment
TUNER side adjustment (Press the tuning UP/DOWN key to move the cursor and press the volume UP/DOWN key to
make an adjustment.)
• Horizontal size adjustment (LCD adjustments)
• Video adjustment (other adjustments)
Y delay
Subcontrast
Subcolour
Subbrightness
Tint offset
AGC gain start
The TUNER side adjustment is possible. However, it is recommended to replace EAROM (I2).
make an adjustment.)
• Horizontal size adjustment (LCD adjustments)
• Video adjustment (other adjustments)
Y delay
Subcontrast
Subcolour
Subbrightness
Tint offset
AGC gain start
The TUNER side adjustment is possible. However, it is recommended to replace EAROM (I2).
Brightness
Contrast
Colour
: select
M: Back
E: End
E: End
Direct control at TV
LC-20A2E
10
PAL/PAL60
SECAM
NTSC
y delay
7
6
0
RF
tint offset
0
0
0
sub contrast
2
2
0
sub colour
25
25
0
y delay
7
5
4
AV1/
tint offset
1
1
1
AV2
sub contrast
0
2
0
sub colour
30
30
20
y delay
7
5
1
AVS
tint offset
1
1
1
sub contrast
0
0
0
sub colour
30
30
30
AGC gain start
27
3-1. +B adjustment
Page 9 of MAIN side adjustment process +B-ADJ
Adjust the voltage of the pin 12 of SC901 the SUB PWB to 5.0V
Adjust the voltage of the pin 12 of SC901 the SUB PWB to 5.0V
±
0.05V.
3-2. Model setting
Page 9 of MAIN side adjustment process MODEL
Set to A2E.
Set to A2E.
3-3. Inch size setting
Page 9 of MAIN side adjustment process INCH SIZE
Set to 20.
Set to 20.
3-4. COMMON BIAS adjustment of LCD module
Page 9 of MAIN side adjustment process COM BIAS
Input the picture of gray scale and adjust it so as to obtain the best contrast.
Input the picture of gray scale and adjust it so as to obtain the best contrast.
3-5. CUTOFF adjustment
Page 9 of MAIN side adjustment process R CUTOFF, B CUTOFF
Adjust it so as to obtain the optimal colour balance.
Adjust it so as to obtain the optimal colour balance.
LC-20A2E
11
TROUBLE SHOOTING TABLE
No picture, No sound
Check all the settings microprocessor's adjust process menu.
Do F2, F3 and F4
function?
Are T701's secondary
outputs, +38V, +16V, +9V,
+5V and -8V normal?
Remove F2, F3 and F4
and check the load side.
Is there short-circuiting?
Is there short-circuiting of
T701 primary side periphery,
Q751, Q753 and S4701.
Replace F2, F3 and F4.
Check S4701 and
connection cable.
Is T701's primary oscillator
waveform normal?
Check T701's secondary
load.
Yes
Yes
No
No
No
No
Yes
Fluorecent lamp failure to light up
Does F1 function?
Is the pin 34 of IC1201 in
the "H" state?
Is the Q3603 short-circuiting?
Is there short-circuiting of
T7751~7756 primary side
periphery, Q7751~Q7755.
Yes
Yes
No
No
No
Yes
Replace the fluorecent lamp
with new one and check
again.
Yes
Check the OFL1 line, IC1201
and their peripheral parts.
Check Q3603 and their
peripheral parts.
Check T7751~T7756,
Q7751~Q7755 and
connection cable.
LC-20A2E
12
TROUBLE SHOOTING TABLE
(Continued)
No picture
Check all the settings microprocessor's adjust process menu.
Is in/output of
IC801 normal?
Is in/output of
IC1201 normal?
Check IC801
and its
peripheral parts.
Check IC1201
and its
peripheral parts.
Check IC402
and its
peripheral parts.
Check IC801,
AV1 line and its
peripheral parts.
Check LCD
panel voltages
and waveform.
Yes
Yes
No
No
No picture
at all
Is in/output of
IC402 normal?
Is input at pin
73 of IC801
normal?
Yes
No
No
No TV and
VIDEO 1
output
Is voltages at
pin 3 of W7 and
pins 3, 4, 5 of
W14 tuner
normal?
Is output at pin
2 of W7 tuner
normal?
Check the
power line.
Check tuner
and its
peripheral parts.
Is input at pin
3 of IC402
normal?
Is the pins 2
and 4 of IC402
at "H" and "L"
state?
Yes
Yes
No
No
No
No
No
Yes
No TV output
Is the pins 65
and 66 of
IC2001 at "H"
and "L" state?
Yes
Check the its
line.
Check the its
line.
Check IC402
and its
peripheral parts.
Is input at pin
1 of IC402
normal?
Is the pins 2
and 4 of IC402
at "L" state?
Check the its
line.
Check the its
line.
Check IC402
and its
peripheral parts.
Is the pins 65
and 66 of IC2001
at "L" state?
Yes
Yes
No
No
No
No VIDEO 1
output
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