LC-20M4E (serv.man2). Part 1 - Text (1-11) - Sharp TV Service Manual (repair manual). Page 9

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

:UADP-0218CEZZ

DC power supply :13 V, 3.8 A
Use also a SHARP TV remote controller.

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.

●

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.)

●

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.

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.

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.

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

±

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.