Acer AL1921 - Chapter 4 Troubleshooting

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Troubleshooting
This chapter provides troubleshooting information for the AL1921:
Main Board
1. No Screen Appear
Note:1.If Replace “MAIN-BOARD” ,Pleasere-do “DDC-content” programmed & “WHITE-Balance”.
2. If Replace “Power Board” only, Please re-do “ WHITE-Balance”.
Chapter 4
Yes
,
all DC level exist
Led Green
NG
OK, U203 data OK
OK,clock
normal
Measured U201 pin 2 = 2.5 V?
Measured U202 pin 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 U601
MCU
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 U601 pin 4,10 ,was there have
signal ?
Check Corresponden
t
component short/open
( Protection Diode )
and Signal cable bad ?
OK,Wire tight enough
Check Panel-Power Circuit
OK,Panel Power OK
Check U602 Data-output Block
Replace Power board and Check
Inverter control relative circuit
Re-do White balance adjust
OK,input Normal
Measured Crystal X401(14.318MHz)
Replace U401 (MST8131B)
OK