Dell ST2010 - 20" LCD Monitor, Руководство по обслуживанию

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Service Manual
14
HDMI cable the U105#3pin will receive a high signal and system enter self test
mode when exit factory mode
（
the device must set at HDMI input mode
）
.
- U204 is an EEPROM IC which is memory and HDMI input EDID data saved
in it ,the U204 power is supplied by PC via CN201#18 through D201, or
supplied by Monitor self via D201.
2.3.3 Buttons Control
- Button “Power” on right corner of front bezel connects to U105
(TSUM58EDJ-LF ) #119 through CN104 #1 and R153, U105 #119 is defined
as power on/off.
- Button “+” and “-” on right corner of front bezel connects to U105
(TSUM58EDJ-LF) #120 through CN104 #2and R154, U105#120 is defined as
“Plus and minus” using with AD converting control technology.
- Button “Menu” and “Exit”on right corner of front bezel connects to U105
(TSUM58EDJ-LF) #121 through CN104 #4and R155, U105 #121 is defined
as “Menu”and “Exit” using with AD converting control technology.
- LED Indicator on Front Bezel
a. When press button “power”, U105 (TSUM58EDJ-LF) #123 be send in low
Voltage, make Q107#3 sends out high Voltage to CN104#3 , and then to
keypad, LED blue on.
b. When in “Suspend” mode, U105 (TSUM58EDJ-LF) #124 sends out a low
Voltage, make Q108#3 sends out high Voltage to CN104#5 , and then to
keypad, LED Amber on.
2.3.4 MAIN CHIP U105 (TSUM58EDJ-LF )
- U105 (TSUM58EDJ-LF ) #86~#77 output 8 bit even and #100~#91 output 8
bit odd LVDS digital data to panel control circuit through CN103.
- U105 (TSUM58EDJ-LF ) #73 output PPWR ”H” potential to make Q104
conducted, and then make Q101 conducted, +5V flow to CN103#1~#3 as
Panel Vdd .
- U105 (TSUM58EDJ-LF) #125 outputs Brightness “PWM” signals to control
CCFL brightness and on/off.
- TCLK by Crystal 14.318MHz input to U105 (TSUM58EDJ-LF) #128.
- U105(TSUM58EDJ-LF) #108 is RESET signals input pin
Please refer to TSUM58EDJ-LF Pin Assignments table in page
2.3.5 Regulator Circuit
- +5V is from switching power supply .
- +3.3V is generated from Regulator U101 which is supplied by+5V through
C101 filtering, C102 and C105 is 3.3V which supplies toU102
、
U106
、
U103
、
U201
、
U105
、
U108output filtering.
- +1.8V is generated from Regulator U102 which is supplied byU101-3.3V
through C106 filtering.TheU102 output1.8V via FB105 send to U105.
3. FACTORY PRESET TIMING TABLE
3.1 VGA