AOC Vibrant VL7A9DA Service Manual page 18

II (a) THE SCREEN is Abnormal , stuck at white screen, OSD window can't appear, but
keyboard & LED was normal operation.
At general, this symtom is cause by missing panel data or panel power, so we must check our
wire-harness which connected to panel or the panel power controller (U202)
Check if the Wire harness from CN601 & CN602 loose?
Check the wire on both Panel-side and Mainboard side.
Yes, tight enough
Check the Panel-Power circuit as above (page 15)
U202 pin 5,6,7,8 ,must be 5V
Yes, Voltage normal
Check the LVDS-Power L603,L604,L601,L602,L900= 3.3V ?
Yes, Voltage normal
Check the both U601 & U602 LVDS-Input pin 31= 45mhz –
65mhz, and pin 27 = Vsyn freq,
Yes, Frequency normal
Replace both LVDS chip ( U601 & U602)
II. (b)The screen had the Vertical Straight Line, might be stuck in Red, Green, Blue
That symptom is cause by bad Panel issue ( might be the Source IC from Panel is cold solder or
open loop ) so REPLACE THE PANEL TO NEW ONE.
pin 28 = 45khz- 65 khz
NG
Tighten it.
NG
Check U904,which convert the 5V to
3.3V
Check U200 DATA-OUPUT block as
above ( page 15)
Check OSCILLATOR Block as
above ( page 15)
Replace U302 MCU and check it RESET
pin 10 ,must be turn high to low when first
AC power-on
OK, reset is normal
Check U200 DATA-OUTPUT block again
NG,still no data out
Replace U200 GMZAN1
NG,no data output
OK,all clock is normal