Service manual

Page 1
AL1702
1) Circuit Description
1.Power Board Operation Therory--------------------------------------------------------------------------------------------3
2.Inverter--------------------------------------------------------------------------------------------------------------------------4
3.Interface-------------------------------------------------------------------------------------------------------------------------5
3.1 Top---------------------------------------------------------------------------------------------------------------------------5
3.2 Power------------------------------------------------------------------------------------------------------------------------5
3.3 VGA & DDC interface-----------------------------------------------------------------------------------------------------5
3.4 Scaler MST8111A---------------------------------------------------------------------------------------------------------5
3.5 Panel interface--------------------------------------------------------------------------------------------------------------5
3.6 Audio------------------------------------------------------------------------------------------------------------------------7
4.Others---------------------------------------------------------------------------------------------------------------------------7
4.1 Detection of POWER switch status------------------------------------------------------------------------------------7
4.2 Display mode identification----------------------------------------------------------------------------------------------7
4.3 Power ON sequence------------------------------------------------------------------------------------------------------8
4.4 Power OFF sequence-----------------------------------------------------------------------------------------------------8
4.5List of I/O Pin Assignments of the I307--------------------------------------------------------------------------------9
2) Trouble Shooting
1.No display of screen (Screen is black, color of LED is amber)--------------------------------------------------------11
2.Nothing displays on screen (Screen is black, color of LED is green)------------------------------------------------12
3.Checking the back light unit-----------------------------------------------------------------------------------------------15
4.Abnormal screen-------------------------------------------------------------------------------------------------------------16