Adjusting Procedure Of Each Section - Sharp LC-20M4U Service Manual

LC-20M4U

ADJUSTING PROCEDURE OF EACH SECTION

When the microprocessor (IC2001) or the E
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 :UADP-0220CEZZ
DC power supply :13 V, 3.8 A
Use also a SHARP TV remote controller.
1. Adjustment procedure
Power on (initialization)
Counter bias adjustment
Calling the adjustment process 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.
Using the keys for the adjustment process
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.)
Other key-in behaviors
The input select key serves also as a toggle switch.
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 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.
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 M4U in the MODEL item.
Select 20 in the INCH SIZE item.
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.
1-2. +B adjustment
Feed the standard NTSC color 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 ± 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.
2 PROM (IC2004) has been replaced or when the E
Adjustment process mode (remote controller)
White balance adjustment
Adjustment process page 1.
Adjustment process page 1.
+B adjustment
Performance check Factory settings
10
2 PROM has been initial-