L32DIGB20 Service Manual.doc

Service Manual

Service Manual L32DIGB20

LCD V Service Manual

1.Diagram:

LVDS Cable

M/B CN10 to panel

LVDS connect

M/B J28 J29 to speaker

Power Board CON4 to panel

Power Board

POWER INPUT

Power Board to M/B J1

IR Board/Keypad Board

M/B CN11 to IR Borad

1.1 Function of Board：

1) Iamge Board(M/B)：Control all input signals, Decode the video signal, De-interlace, and send digital

signals (LVDS signal) sent from image Board and display;

2) Panel：Display all image;

3) Key Pad Borad： POWER、SOURCE、MENU、VOL+/- ,Channel +/-;

4) IR Board ：Recive IR Signal; LED R/G

5) Power Board: the Power Supply for Panel , Image Board;

1.2 Part apt to decrease：

1) Bezel 、Rear Cover ,Panel.

2) Terminal of all plug

2、Basic diagram：

2.1 power diagram

2.2 video system diagram

3、Basic schematic of part

3.1.  mute circuit

3.2. S-video in

3.3. Spdif out

3.4. YPBPR

3.6. main supply circuit

3.7  3.3V supply circuit

3.8  1.2V power circuit

3.9、DDR supply circuit

3.10、Tuner 5V supply circuit

3.11、2.5V power circuit

3.12、LED Driver control circuit

3.13、Reset circuit

3.14、1.8V power circuit

4、Basic schematic of Power Board

5 、MTK5303C    frequently   malfunction  obviate：

（1）、Malfunction of three nothing(no power  no picture no sound)

Check Power Supply

The power plate no output or +5V_stby pin is short

M/B  J1 Pin10 no 5VSB?

Power LED lighting or no？

   No                  No

Check the Power Net

Yes                                          Yes

whether the LED is blue after turning on TV with  remote controller

malfunction IR control Board ,especially LED

check IR control Board

              No             

   YES

Check CPU, DDR power supply circuit（U11-1.8V，R29-1.8V，L755-3.3V ，CB42-1.1V，L2-1.1V）

check M/B J1 8pin and 9 pin +5V?,the 1pin and the 2 pin is 12V?

Check U11，N803，U3 around the circuit

              No              No

DDR UA1,FLASH U17 or there are problems around the circuit

Check +5V pin and +12v pin is short circuit

Yes                                       Yes

（2）、no picture but has sound

Check the backlight power no output or short circuit

Check the backlight power voltage 12V ?

Check backlight is lit?

                     No                           No

              否             

Check M/B J14 4PIN on/off control 2V-5V?check it`s circuit is shorted?

         Yes                            

Check the LVDS power 12V or 5V ?(26/32 pannel 12V)

Yes

Check U46 around circuit

  Yes                                ...