Sharp LC-20M4E (serv.man8) Service Manual ▷ View online
7
LC-20M4E
8. Remove the Main PWB fixing screws (4 pcs.).
9. Remove the Inverter PWB fixing screws (3 pcs.).
10. Remove the Jack PWB fixing screw (1 pc.) and Ground fixing screw (1 pc.),
and then remove the Reinforcement plate.
11. Remove the LCD unit fixing screws (2 pcs.).
12. Remove the Switch PWB fixing screws (3 pcs.).
Reinforcement
plate
plate
LCD unit
Main PWB
Jack PWB Ass'y
Switch PWB
Cabinet A
Inverter PWB
12
11
8
9
10
11
P3204
P3203
7
10
8
LC-20M4E
8
»
Precautions in handling the LCD panels
1. Work in a clean room (with humidities below 50%).
2. Be sure to wear an anti-static armband.
3. Handle the panels on an electro-conductive mat.
4. Be careful not to fall, shake and shock the panels.
13. Remove the LCD unit fixing screws (4 pcs.) and
the Rear surface fixing screws (3 pcs.), and then
detach the Shielding plate.
14. Detach the 2 Reflection sheets .
15. Detach the upper and lower Fluorescent lamps.
16. Detach the Light guide plate.
17. Detach the upper and lower Reflection mirrors.
18. Detach the Diffusion sheet and the Reflection
polarising sheet.
Fluorescent lamp (Upper)
(KLMP-0133CEZZ)
(KLMP-0133CEZZ)
Refrection Mirror (Upper)
(PSHEP0223CEZZ)
(PSHEP0223CEZZ)
LCD unit
(CLCDT0060CEZZ)
(CLCDT0060CEZZ)
Fluorescent lamp (Lower)
(KLMP-0134CEZZ)
(KLMP-0134CEZZ)
Refrection Mirror (Lower)
(PSHEP0224CEZZ)
(PSHEP0224CEZZ)
Diffusion sheet
(PSHEP0179CEZZ)
(PSHEP0179CEZZ)
Light guide plate
(PGiDM0058CEZZ)
(PGiDM0058CEZZ)
Reflection polarizing sheet
(PSHEP0180CEZZ)
(PSHEP0180CEZZ)
Reflection sheet-2
(PSHEP0187CEZZ)
(PSHEP0187CEZZ)
13
13
14
15
18
17
15
17
16
Reflection sheet-1
(PSHEP0186CEZZ)
(PSHEP0186CEZZ)
Shielding plate
(PSLDM4712CEFW)
(PSLDM4712CEFW)
LCD unit
(Front surface)
(Front surface)
13
13
9
LC-20M4E
ADJUSTING PROCEDURE OF EACH SECTION
When the microprocessor (IC2001) or the E
2
PROM (IC2004) has been replaced or when the E
2
PROM has been initial-
ized, it is necessary to readjust the microprocessor. Below discussed is the adjustment procedure.
Preparations
Use a dedicated AC adapter or a regulated DC power supply.
AC adapter
Use a dedicated AC adapter or a regulated DC power supply.
AC adapter
:UADP-0218CEZZ
DC power supply :13 V, 3.8 A
Use also a SHARP TV remote controller.
Use also a SHARP TV remote controller.
1. Adjustment procedure
Power on (initialization)
→
Adjustment process mode (remote controller)
→
+B adjustment
→
Counter bias adjustment
→
White balance adjustment
→
Performance check
→
Factory settings
Calling the adjustment process mode
There are the following two ways to enter this mode.
There are the following two ways to enter this mode.
●
Turn on the power and press the “ADJUST PROCESS” key on the remote controller.
●
While holding either KEY4 (pin (81) of the microprocessor) or KEY5 (pin (82) of the microprocessor) at the “L” level,
turn on the power.
turn on the power.
Using the keys for the adjustment process
Selecting an adjustment item and adjusting its setting
Selecting an adjustment item and adjusting its setting
●
Using the menu button (M key), select an item, and using the VOL+/- buttons, adjust its setting.(The menu button
serves as a toggle switch. New settings entered with the VOL buttons are made effective immediately.)
serves as a toggle switch. New settings entered with the VOL buttons are made effective immediately.)
Other key-in behaviors
●
The input select key serves also as a toggle switch.
The input is switched from AV1 to AV2.
The input is switched from AV1 to AV2.
●
Press the auto preset button on the remote controller in the adjustment process mode, and the top item of the next
page will show up regardless of which item appears now.
Page 1
page will show up regardless of which item appears now.
Page 1
→
Page 2
→ ......
→
Page 6
→
Page 1
●
Press the manual memory button on the remote controller in the adjustment process mode, and the top item of the
same page will show up.
same page will show up.
1-1. Initialization
Ground the pins (81) and (82) of IC2001 (microprossor) and turn on the power. The unit will be initialized and then
enter the adjustment process mode.
Select M4E in the MODEL item.
enter the adjustment process mode.
Select M4E in the MODEL item.
Adjustment process page 1.
Select 20 in the INCH SIZE item.
Adjustment process page 1.
Turn off the power and get the pins (81) and (82) of IC2001 (microprossor) back to their original state.
* Before turning off the power, quit the adjustment process mode with the remote controller. If unavoidably
the power must be switched off directly, wait at least 5 seconds after making the settings.
* Before turning off the power, quit the adjustment process mode with the remote controller. If unavoidably
the power must be switched off directly, wait at least 5 seconds after making the settings.
1-2. +B adjustment
Feed the standard NTSC colour bar signal.
Enter the adjustment process mode.
Adjust the “+B-ADJ” setting on the adjustment process page 1 so that the voltage at pin (5) of P2001 should be
5.00
Enter the adjustment process mode.
Adjust the “+B-ADJ” setting on the adjustment process page 1 so that the voltage at pin (5) of P2001 should be
5.00
±
0.02 V.
Note: Make the 5.0V adjustment as exactly as possible because this voltage this voltage will be reference level for all
the supply voltages.
LC-20M4E
10
1-3. Counter bias adjustment
Keep off the video input signal.
Place the specified tool at the center of the screen.
Observe the output of the tool on the oscilloscope screen.
Adjust the “COM BIAS” setting on the adjustment process page 2 so that the peak-to-peak level of the waveform
should be minimum.
Place the specified tool at the center of the screen.
Observe the output of the tool on the oscilloscope screen.
Adjust the “COM BIAS” setting on the adjustment process page 2 so that the peak-to-peak level of the waveform
should be minimum.
1-4. White balance adjustment
Feed the NTSC monoscope pattern signal.
Adjust the “RCUTOFF” and “BCUTOFF” settings on the adjustment process page 2 so as to obtain the colour of the
same level as the standard monitor.
Adjust the “RCUTOFF” and “BCUTOFF” settings on the adjustment process page 2 so as to obtain the colour of the
same level as the standard monitor.
Note: For the “RCUTOFF” and “BCUTOFF” settings, keep the readings in the range of -9 to +9. If out of this range, the
user-adjustable range is reduced.
Adjust them in the indication value range of -9, -7, -5, -3, -1, +1, +3, +5, +7, +9 (odd numbers). When it becomes
even-numbered value (include 0), side favor noise sometimes occurs in the monochrome signal of the specific
gradation.
gradation.
Do not change the “GCUTOFF” settings (It also change the black level).
1-5. Factory setting
Set the product’s input mode, picture quality and other factors to their factory setting.
There are the following two ways.
There are the following two ways.
●
With the keys of the set
In the inspection process mode, hold down both the “SELECT(
In the inspection process mode, hold down both the “SELECT(
▲
)” and “VOL (+)” buttons of the set until “SETTING
COMPLETE” appears on the screen.
Note: Be careful not to turn off the power, release the above two keys and press any other keys until “SETTING
COMPLETE” appears on the screen.
●
With the adjustment remote controller
With the adjustment remote controller, make the factory settings. Either of the following remote controllers codes
will do.
With the adjustment remote controller, make the factory settings. Either of the following remote controllers codes
will do.
Calling the Inspection process mode
There are the following two ways.
There are the following two ways.
●
With the keys of the set
Hold down the “MENU” and “AV INPUT” buttons of the set and turn on the power.
Hold down the “MENU” and “AV INPUT” buttons of the set and turn on the power.
●
With the adjustment remote controller
Use the inspection process key.
Use the inspection process key.
Key name
Remote controller code
Factory setting
100000111111110
Factory setting
100000001010110
E
Changing on-screen display
K
Inspection process mode
Factory setting
Setting complete
SETTING COMPLETE
→
→
E
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