46
2.Panel-Power Circuit
3.Inverter Control Relative Circuit
Yes
Check R302 should have response
from 0V to 5V
When we switch the power switch
from on to off
NG
Check the PPWR panel power relative circuit,
Q301, Q302(pin 5,6,7,8)
In normal operation, when LED =green, R302
should =0 v,
If PPWR no-response when the power switch
Turn on and turn off, replace the U203-MST8131B
OK,R308 have response
NG, no Voltage
Measured the Q302 pin 5,6,7,8= 5 V?
Check U202 pin 1,2,3,4= 5V
OK
OK
Replace Q302 ( Nmos, SI9933)
NG
Check the Bklt-On relative circuit, R409,
In normal operation, when LED =green,
R409 Bklt-On should =5 v,
If Bklt-On no-response when the power
switch turn on-off,
Replace U203 MST8131B
NG, still no screen
Replace Power board to new-one, and
Check the screen is normal ??
OK
NG
Replace Power board
& Re-do white balance
Measured the inveter connector CN402
Pin2 on/off control=3.3V (on)
Pin4 PWM signal control dim 0V-5V
Summary of Contents for AL1921
Page 19: ...18 Monitor Board Layout ...
Page 24: ...23 Front Bezel Item Description 1 VEDIO UP 2 VEDIO DOWM 3 POWER 4 MENU ENTER 5 AUTO EXIT ...
Page 25: ...24 Rear Bezel Item Description 1 D SUB Cable 2 DVI CABLE 3 AUDIO CABLE 4 AC POWER CORD ...
Page 36: ...35 Step2 Select Bank where is the new firmware ...
Page 38: ...37 Step4 Select the communication Setting Port Name the Port the same your PC COM ...
Page 39: ...38 Step5 Click the ConNect button ...
Page 41: ...40 Step7 ISP is processing ...
Page 42: ...41 Step8 Then you can get the window as follow and Program ok ...