Service Manual
11
- +5V is from switching mode power supply for panel and Regulater U601
- +3.3V generates from Regulater U601 supply for U401, U301, U402 used.
- +1.8V generates from Regulater U602 through C603, C604 filtering which is output +1.8V for U401
used.
3. FACTORY PRESET TIMING TABLE
Standard Resolution Horizontal Frequency
(KHz)
Vertical Frequency
(Hz)
640 x 480 31.469 59.940
640 x 480 37.500 75.000
800 x 600 37.879 60.317
800 x 600 46.875 75.000
1024 x 768 48.363 60.004
1024 x 768 60.023 75.029
1152x864 67.500 75.000
1280x1024 48.483 60.042
VESA
1280x1024 60.087 75.034
IBM DOS 720 x 400 31.469 70.087
4. Power On/Off Sequency
Hardware Power ON
When power cord plug into AC socket, Power provides 12V,&DC_5V from through U850, DC_3.3V be
generated from DC_3.3V Regulater U601.DC_5V is voltage for panel, DC_3.3v is main voltage for
U401. When DC_3.3V input to U401, U401 reset circuit active, set U401 all registers to default,. That
means finish hardware power on.
Software Power ON/OFF
When press power key, U401 #125 recieves low pulse, and then (gm2621-LF) U401 will be wake up and
send high plus(at 127,49pin) to on CCFL and switch 5.0v to panel module. And make the VGA cable input
signal source display normal on panel.
- If Power ON, U402 #57 (LED_Green) will send out High potential, and then LED green on.
- If Power OFF, U402 #56 (LED_Amber) will send out High potential, and then LED Amber on.
The Panel_Vcc, Backlight_En, CLK/DATA output to panel will follow the following sequency.
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