Dell S1909WXf Service Manual page 12

ZD109 is ESD protector.
- U102 +3.3V is supplied by PC via CN101#9 with D104 and ZD101 for ESD protection, or
supplied by Monitor self via D104.
- U102 is an EEPROM IC which is memory and EDID data saved in it.
2.3.2 DVI CAPTURE
- Differential Signal input RX0+,RX0-,RX1+,RX1-,RX2+,RX2-,RXC+,RXC- through CN102
#18,#17,#10,#9,#2,#1,#23,#24 via R130,R131,R132,R133,R134,R135,R137,R138 enter
into U104 (TSUM56BWHK-LF) Digital input terminal #39,#40,#42,#43,#45,#46,#48,#49,
and then TSUM56BWHK-LF deals with signal internally. D108, D109, D110, D111, D112,
D113, D114, D115 are ESD protector to prevent U104 from ESD
- Signal DDC_SCL (series clock) inputs via CN102#6, and then passes through ZD106 Zener
for ESD protection, via R126, goes into EDID EEPROM IC U101 #6.
- Signal DDC_SDA (series data) inputs via CN102#7, and then passes through ZD107 Zener
for ESD protection, via R127, goes into EDID EEPROM IC U101 #5.
- CN102#15 is defined as cable detect pin, this detector realize passes through R125 ,go into
U104#27, and ZD110 is ESD protector.
- U101 +5V is supplied by PC via CN102#14 through D107, or supplied by Monitor self via
D107.
- U101 is an EEPROM IC which is memory and DVI input EDID data saved in it.
2.3.3 Buttons Control
- Button "Power" on front bezel connects to U104 (TSUM56BWHK-LF) #23 through CN104 #1,
U104 #23 is defined as power on/off.
- Button " " on front bezel connects to U104 (TSUM56BWHK-LF) #24 through CN104 #2,
U104#24 Voltage is defined as "Plus".
- Button " " on front bezel connects to U104 (TSUM56BWHK-LF) #24 through CN104 #2,
U104 #24 Voltage is defined as "Minus".
- Button "Menu" on front bezel connects to U104 (TSUM56BWHK-LF) #25 through CN104 #4,
U104 #25 Voltage is defined as "Menu".
- Button "ENTER" on front bezel connects to U104 (TSUM56BWHK-LF) #25 through CN104
#4, U104 #25 Voltage is defined as "ENTER".
- LED Indicator on Front Bezel
a. When press button "power", U104 (TSUM56BWHK-LF) #31 be send in low Voltage, make
Q109#3 sends out high Voltage , and then to CN01#2 on keypad, LED white on.
b. When in "Suspend" mode, U104 (TSUM56BWHK-LF) #35 sends out a low Voltage, make
Q108#3 sends out high Voltage and then to CN01 #3 on keypad, LED Amber ON.
2.3.4 MATAR CHIP U104 (TSUM56BWHK-LF)
- U104 (TSUM56BWHK-LF ) #105~#114 output 8 bit even and #118~#127 output 8 bit odd
LVDS digital data to panel control circuit through CN106.
- U104 (TSUM56BWHK-LF ) #75 output PPWR "H" potential to make Q106 conducted, and
then make Q103 conducted, +5V flow to CN106#1~#3 as Panel Vdd .
- U104 (TSUM56BWHK-LF) #20 output CCFL_ON/OFF "L" potential to control Inverter on/off.
- U104 (TSUM56BWHK-LF) #21 outputs Brightness "PWM" signals to control CCFL
brightness.
- TCLK by Crystal 14.318MHz input to U104 (TSUM56BWHK-LF) #32.
- U104 (TSUM56BWHK-LF) #19 is RESET signals input pin
Please refer to TSUM56BWHK-LF Pin Assignments table in page
2.3.5 Regulator Circuit
- +5V is from switching mode power supply for panel
- +3.3V is generated from Regulator U103 which is supplied by+5V through C168 filtering,
C130 is 3.3V output filter ,the output 3.3V supplies toU104, U108,U107,U106,U105,U102,
U101.
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Service Manual