34
Troubleshooting
This chapter provides troubleshooting information for the AL1721h:
Main Board
1.No Screen Appear
Note:1.If Replace “
MAIN-BOARD
” , Please re-do “DDC-content” programmed &
“WHITE-Balance”.
2. If Replace “
Power Board
” only, Please re-do “ WHITE-Balance”.
Yes, all DC level exist
Led Green
NG
OK, U203 data OK
OK,clock
normal
Measured U503 pin 2 = 2.5 V?
Measured U502 pin 2= 3.3V?
Measured U501pin 2 =3.3V?
Check Correspondent component.
Is there any shortage or cold solder?
Check Power Board.
Yes.there have OSD show
Disconnected the Signal cable( Loose the
Signal cable ),Is the screen show “Cable Not
Connected the Signal cable again,
Check LED status.
Led Green
Replace U202
Flash Rom
No, nothing is show
Connected the Signal cable again,
Check LED status.
Check Power switch is in Power-on
status , and check if Power switch had
been stuck ?
Led Orange
OK, Keyboard no stuck
Led orange
Check the Wire-Harness from CN301
Measured RGB (R136,R138,R140) H,V
Input at U106 pin 4,10 ,was there have
signal ?
Check Correspondent
component short/open
( Protection Diode )
and Signal cable bad ?
OK,Wire tight enough
Check
Panel-Power Circuit
OK,Panel Power OK
Check
U203 Data-output
Block
Replace
Power board
and Check
Inverter
control relative circuit
Re-do White balance adjust
OK,input Normal
Measured Crystal X201(14.318MHz)
Replace
U203 (GM5120)
OK
Chapter 4
