Dell UltraSharp 2208WFP User manual

Service Manual
0
Service Manual
LCD Monitor 2208WFP

1
Service Manual Versions and Revision
No.
Version
Release Date
Revision
1
1.0
2008-7-17
Initial Release
Copyright
Copyright 2007 InnoLux Display. Corp. Ltd
All Rights Reserved
This manual may not, in whole or in part, be copied, Photocopied, reproduced, translated, or converted to any
electronic or machine readable form without prior written permission of Foxconn Tech. Corp. Ltd.
Dell 2208WFPf Service Manual

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Table of Contents
CHAPTER 1- PRECAUTIONS & SAFETY NOTICES ...................................................................................................................... 3
1. SAFETY PRECAUTIONS ...................................................................................................................................................... 3
2. PRODUCT SAFETY NOTICE ............................................................................................................................................... 3
3. SERVICE NOTES ................................................................................................................................................................... 3
CHAPTER 2- SERVICE TOOLS & EQUIPMENT REQUIRED....................................................................................................... 4
CHAPTER 3- CIRCUIT THEORY ........................................................................................................................................................ 5
1. BLOCK DIAGRAM ..................................................................................................................................................................... 5
2. ELECTRONIC CIRCUIT THEORY ................................................................................................................................................ 7
3. FACTORY PRESET TIMING TABLE ................................................................................................................................. 13
4. POWER ON/OFF SEQUENCY ................................................................................................................................................... 13
5. D-SUB CONNECTOR PIN ASSIGNMENT .................................................................................................................................. 14
6. AC OUTLET PIN ASSIGNMENT ............................................................................................................................................... 14
7. INNER CONNECTOR PIN ASSIGNMENT .................................................................................................................................... 14
8. KEY PARTS PIN ASSIGNMENTS ............................................................................................................................................... 16
CHAPTER 4- DISASSEMBLY & ASSEMBLY .................................................................................................................................. 21
1. EXPLODED DIAGRAM ............................................................................................................................................................. 21
2. 2208WFP DISASSEMBLY BLOCK............................................................................................................................................ 22
3. ASSEMBLY BLOCK.................................................................................................................................................................. 23
CHAPTER 5- TEST AND ADJUSTMENT ......................................................................................................................................... 24
1. FUNCTION KEY DEFINITIONS .................................................................................................................................................. 24
2. OSD CONTROL....................................................................................................................................................................... 24
3. FACTORY MODE INTRODUCTION ............................................................................................................................................ 26
4. BURN-IN PATTERN .................................................................................................................................................................. 27
5. AUTO COLOR BALANCE (AUTOMATICALLY CALIBRATE CHIP ADC PARAMETER BY USING CHIP INTERNAL DAC.) ................ 27
6. UPLOAD FIRMWARE TO MCU VIA VGA CABLE...................................................................................................................... 32
7. AFTER REPAIR,TO ENSURE THE QUALITY YOU SHOULD DO THE FOLLOWING TEST AND ADJUSTMENT. ................................... 27
CHAPTER 6- TROUBLE SHOOTING ............................................................................................................................................... 30
1. COMMON ACKNOWLEDGE...................................................................................................................................................... 30
2. NO POWER LED OFF.............................................................................................................................................................. 30
3. POWER NORMAL LED AMBER................................................................................................................................................ 31
4. BACKLIGHT CAN’T BE TURNED ON ......................................................................................................................................... 38
5. NO PICTURE BACKLIGHT ON ................................................................................................................................................ 39
6. AT 32-GRAY SCALE PATTERN,COLOR LOST IN SOME SCALE .................................................................................................... 40
CHAPTER 7- RECOMMENDED PART LIST................................................................................................................................... 35
ATTACHMENT 1- BILL OF MATERIAL .......................................................................................................................................... 37
ATTACHMENT 2- SCHEMATIC ........................................................................................................................................................ 47
ATTACHMENT 3- PCB LAYOUT....................................................................................................................................................... 60

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Chapter 1- PRECAUTIONS & SAFETY NOTICES
SAFETY PRECAUTIONS
This monitor is manufactured and tested on a ground principle that a user’s safety comes first.
However, improper used or installation may cause damage to the monitor as well as to the user.
WARNINGS:
This monitor should be operated only at the correct power sources indicated on the rating label on
the rear cover of the monitor. If you’re unsure the power supply in your residence, consult your
local dealer or Power Company.
Use only the specified power cord that comes with this monitor.
Do not try to repair the monitor by yourself, as it contains no user-serviceable parts. This monitor
should only be repaired by a qualified technician.
Do not remove the monitor cabinet. There is high-voltage parts inside that may cause electric shock
to human bodies.
Stop using the monitor if the cabinet is damaged. Have it checked by a service technician.
Put your monitor only in a lean, cool, dry environment. If it gets wet, unplug the power cable
immediately and consult your closed dealer.
Always unplug the monitor before cleaning it. Clean the cabinet with a clean, dry cloth. Apply
non-ammonia based cleaner onto the cloth, not directly onto the class screen.
Do not place heavy objects on the monitor or power cord.
PRODUCT SAFETY NOTICE
Many electrical and mechanical parts in this chassis have special safety visual inspections and the
protection afforded by them cannot necessarily be obtained by using replacement components rated
for higher voltage, wattage, etc. Before replacing any of these components read the parts list in this
manual carefully. The use of substitute replacement parts, which do not have the same safety
characteristics as specified in the parts list, may create shock, fire, or other hazards.
SERVICE NOTES
When replacing parts on circuit boards, clamp the solder wires around terminals before soldering.
Keep wires away from high voltage, high temperature components and sharp edges.
Keep wires in their original position so as to reduce interference.
Adjustment of this product please refers to the user’ manual.
Use Pb free solder wire for circuit board preparation.

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Chapter 2- SERVICE TOOLS & EQUIPMENT REQUIRED
1. SIGNAL GENERATOR
2. MULTIMETER
3. SCREW DRIVER
4. OSCILLOSCOPE
5. Soldering IRON
6. SOLDER (Lead free, RoHS compliance)
7. Color Analyzer
8. Realtek ISP_Programmer
9. Fox_VEDID_Programmer

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Chapter 3- CIRCUIT THEORY
Block Diagram
There are 4pcs PCBA in this monitor, one is power& inverter&Audio board which is a single layer board,
one is interface board including USB HUB 1up/2down, one is keypad which is OSD control, and one is
USB transfer board located on the right side back cover. The system function block diagram as below
This PWA is included switching power supplier, inverter for CCFL and interface board.(fig.1)
Fig.1
INVERTER
POWER

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Fig.12

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Electronic Circuit Theory
2.1 Inverter PWM circuit
2.1.1)Inverter Control circuit:(fig.2)
Fig.2

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+5VDC provides the power for U1; the control signals Brightness and ON/OFF come from I/F
board. ON/OFF signal connect to pin16 of U1 and makes U1 enable. Brightness signal connect to
pin13 of U1 and regulates the brightness of panel .TIMER makes up a network of delaying time
circuit and R23 make up a divided voltage network, C3 and C18 are used to control start-up
timing. The operation frequency is determined by the external Resistor R16 and capacitor C8
connected to pin3 of U1. C7 is used for soft start and compensation.
The output drives, include DRV1, DRV2 (pins6,8,9,10 respectively) output square pulses to
drive MOSFET Q6, Q7 and each of them is consist of a N+P channel MOSFET. Q6 and Q7 work as
All Bridge structure, and it is high efficient, PWM switching.
During start up, VSEN (pin1) senses the voltage at the transformer secondary. When VSEN
reaches 3.0V, the output voltage is regulated. If no current is sensed for approximately 2seconds U1
will shut off.
The current flowing through CCFL is sensed and regulated through sense resistor R6, R19. The
feedback voltage connected to Pin1 (ISEN), then compared with a reference voltage (1.5V) via a
current amplifier, resulting that PWM drive U1 to work and output square pulses for all bridge
switches
2.1.2）Protection Circuit
Over-voltage and over-current protection are monitored by the voltage on VSEN(pin1).During
normal operation,if a CCFL is damaged or removed,the voltage at VSEN exceeds the user-defined, preset
voltage set by OVPT(pin15),the driver output duty cycle is regulated and the shutdown delay timer is
activated.OVPT sets the overall protection threshold voltage that is lower than3V(VSEN threshold. Once
the voltage at TIMER pin reaches 3V,the IC will shut down and latch. OVPT voltage setting is determined
by a resistor divider (R18/R8)connected to the OVPT.
The over-voltage protection feature is implemented by using an external capacitor divider
(C1/C15/C16/C17) to sense the output voltage. The divide-down voltage signal is sent to the IC
Pin1(VSEN) ,thus regulate the output voltage.
If a CCFL is removed, fails or is damaged during normal operation, CCFL current is no longer sensed
and the voltage on ISEN pin drops. The voltage at the SSTCMP(pin2)rises rapidly because there is no
current feedback at ISEN(pin14).When the voltage at SSTCMP reaches a threshold of approximately 2V
and ISEN is less than 0.7V,a current source charges the capacitor(C3) connected to TIMER(pin12).Once the
voltage level at the TIMER pin reaches a threshold of approximately 3V,the drive outputs shut down and
latch.To resume operation,toggle the ENA signal or restart VDDA.
2.2 Power PWM circuit
2.2.1) Block diagram:(fig.4)

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2.2.2) AC Input and EMI Filter:(fig.5)
fig.5
CN850 is a connector for connecting AC Power. F850 is a fuse to protect all the circuit AC. Input
voltage is from 90V to 264V. R850/R851 are joined between two inputting main circuit to prevent man
from shock. L850is used to filter low frequency noise. C850 and C851 are used to discharge the noise that
L850produced. High frequency waves are damped by C852;
2.2.3)High Voltage to Low Voltage Control Circuit:(fig.6)

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fig.6
D850 is a rectifier in which there are 4 build-in diodes, inverting AC to DC.
C854 is used to smooth the wave from rectifier. U850 is a highly integrated PWM controller.
Typical start-up current for U850 is only 20 uA, When current flow through R841/R842/R843 gets to
Pin 3of U850, with VDD hold-up capacitor C855, U850 is enough for starting up.
When U850 begins to operate Pin8 of U850 will output square wave to drive Q850, then the main
current flow get to GND bypassing through T850, Q850. Because of the change of current flow, wires in
the other side of T850 will induct current. In the same time, the current inducted by wires which
connected T850 Pin 1 and Pin 3, with components of D852, R856and C855 ,will be supplied to U850 for
normal operating.
When the sense voltage across the sense resistor R859, reaches the threshold voltage around 0.85v,
the output GATE drive will be turned off. Every time when the output of power supply is shorted or over
loaded, the FB voltage will increase, the build-in PWM output will then be turned off. Both of two will
prevent the power supply from being overheated under over loading condition. The PWM duty cycle is
determined by this current sense signal and VFB, the feedback voltage, when the voltage on sense pin
reaches V-(PWMcopm) =(Vcomp-2VF)/3, A switch cycle will be terminated immediately, Vcomp is internally
clamped to a variable voltage around 0. 85 V for output power limit
When Q850 are turned off, the main current flow will be consumed through D851, C875,
R853/R854/R855 and D853, This will prevent Q850 from being damaged under large current impulse and
voltage spike.
2.2.4) DC_24V ,12Vand 5V Output Circuit and Feedback circuit: (fig.7)

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fig.7
D854&D855 are used to rectify the inducted current. C862 are used to store energy when current is
reversed. The parts including L852 are used to smooth the current waves that are from D854&D855, and
then 24V voltage is supplied.
D880&D881 are used to rectify the inducted current . C881 is used to store energy when current is
reversed. The parts including U880 are used to change the voltage from about 13V to steady 12V ,and then
12V voltage is supplied.
D856 is used to rectify the inducted current. C874,C864&C875 are used to store energy when current is
reversed. The parts including L851,and C876 are used to smooth the current waves that are from D856, and

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then 5V voltage is supplied.
5V supply voltage feed back to PWM controller U850 via R861, R860,and I850,I851.R859,C859 and
C863 are used to control response time.
LD7575 implements an OVP function on Vcc .Whenever the Vcc voltage is higher than the OVP
threshold voltage, the output gate drive circuit will be shutdown simultaneously thus to stop the switching of
the power MOSFET until the next on.
2.3 I/F Board Circuit (see the Attachment 2- Schematic)
2.3.1 RGB CAPTURE
- Signal RED,GREEN,BLUE input through CN102 #1,#2,#3, Stop DC via C113, C114 and C115, and
then enter into U105 (RTD2545LH) analog input PIN #16,#14,#12, and then RTD2545LH deals
with signal internally. D103, D104, D105 are ESD protector to prevent U105 from ESD.
- Signal DDC_SCL (series clock) inputs via CN102#15, and then passes through ZD106 for ESD
protection, goes into EDID EEPROM IC U103 #6.
- Signal DDC_SDA (series data) inputs via CN102#12, and then passes through ZD103 for ESD
protection, goes into EDID EEPROM IC U103 #5.
- Signal TTL vertical sync. (Vsync) inputs via CN102 #14, and then clamped by ZD105 Zener, passes
through R134, and then goes into IC U105 (RTD2545LH) #8.
- Signal TTL horizontal sync. (Hsync) inputs via CN102 #13, and then clamped by ZD102 Zener,
passes through R133, and then goes into IC U105 (RTD2545LH) #9.
- CN102#5 is defined as cable detect pin, this detector realize via R125 and U108#24, and D102 is
ESD protector.
- U103 +5V is supplied by PC via CN102#9 with ZD102 for ESD protection, or supplied by Monitor
self via D106
- U103 is an EEPROM IC which is memory and EDID data saved in it.
2.3.2 DVI CAPTURE

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- Differential Signal input RX0+,RX0-,RX1+,RX1-,RX2+,RX2-,RXC+,RXC- through CN201
#18,#17,#10,#9,#2,#1,#23,#24 via R206,R205,R204,R203,R202,R201,R207,R208 enter into U105
(RTD2545LH) Digital input terminal #4,#5,#2,#3,#47,#48,#6,#7, and then RTD2545LH deals with
signal internally. D206, D207, D204, D205, D202, D203, D208, D209 are ESD protector to prevent
U105 from ESD
- Signal DDC_SCL (series clock) inputs via CN201#6, and then passes through ZD204 Zener for ESD
protection, via R209, goes into EDID EEPROM IC U201 #6.
- Signal DDC_SDA (series data) inputs via CN201#7, and then passes through ZD203 Zener for
ESD protection, via R210, goes into EDID EEPROM IC U201 #5.
- CN201#15 is defined as cable detect pin, this detector realize passes through R216 ,go into U108#25,
and D210 is ESD protector.
- U201 +5V is supplied by PC via CN201#14 through D201, or supplied by Monitor self via D201.
- U201 is an EEPROM IC which is memory and DVI input EDID data saved in it.
2.3.3 Buttons Control

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- Button “Power” on front bezel connects to U108 (RTD2122L) #9 through CN104 #8, U108 #9 is
defined as power on/off.
- Button “+” on front bezel connects to U108 (RTD2122L) #47 through CN104 #4, U105#47 Voltage
is defined as “Plus”.
- Button “-” on front bezel connects to U108 (RTD2122L) #22 through CN104 #3, U105 #22 Voltage
is defined as “Minus”.
- Button “Menu” on front bezel connects to U108 (RTD2122L) #21 through CN104 #2, U105 #21
Voltage is defined as “Menu”.
- Button “SELECT” on front bezel connects to U108 (RTD2122L) #14 through CN104 #1, U105 #14
Voltage is defined as “SELECT”.
- LED Indicator on Front Bezel
a.When press button “power”, U108 (RTD2122L) #1 be send in low Voltage, make Q107#3 sends
out high Voltage , and then to CN01#5 on keypad, LED green on.
b. When in “Suspend” mode, U108 (RTD2122L) #48 sends out a low Voltage, make Q108#3 sends
out high Voltage and then to CN01 #7 on keypad, LED Amber ON.
2.3.4 MATAR CHIP U105 (RTD2545LH)/U108(RTD2122L)
- U105 (RTD2545LH) #21~#28 output 8 bit even and #29~#38 output 8 bit odd LVDS digital data to
panel control circuit through CN103.
- U108(RTD2122L) #39 output PPWR ”H” potential to make Q104 conducted, and then make Q101
conducted, +5V flow to CN103#1~#3 as Panel Vdd .
- U108(RTD2122L) #20 output CCFL_ON/OFF ”L” potential to control Inverter on/off.
- U108(RTD2122L) #44 outputs Brightness “PWM” signals to control CCFL brightness.
- TCLK by Crystal 14.318MHz input to U108(RTD2122L) #15/#16.
- U108(RTD2122L)#4 is RESET signals input pin
Please refer to U105 (RTD2545LH)/ U108(RTD2122L) Pin Assignments table in page
2.3.5 Regulator Circuit
- +3.3V is generated from Regulator U101 which is supplied by+5V via R101 and through C104
filtering,

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-+1.8V is generated from Regulator U102 which is supplied by+3.3V through C106 filtering,
3. FACTORY PRESET TIMING TABLE
Standard
Resolution
Horizontal Frequency
(KHz)
Vertical Frequency (Hz)
720 x 400
31.469
70.087
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
1152 x 864
67.500
75.000
1280 x 1024
64.000
60.000
1280 x 1024
79.976
75.025
VESA
1680 x 1050
65.160
60.0
IBM DOS
720 x 400
31.469
70.087
4. Power On/Off Sequency
Hardware power On/Off
When power cord plug into AC socket, Power provides 26V and DC_5V.
DC_5V is main voltage for panel and Regulator U101.
DC_3.3V is coming from Regulator U101, DC_3.3v is main voltage for U108. When DC_3.3V input to
U108 and U108 reset circuit active, U108 all registers will be set to default, that means finish hardware
power on.
When pull out power cord from AC socket,the system shut down instantly for no supply
Software power On/Off
- When press power key, U108 #9 receives low pulse, then U108(RTD2122L) will be wake up and send
control signals(at 20,39pin) to on CCFL and switch 5.0v to panel module, at the same time,U105 make
the VGA/DVI cable input signal source display normal on panel if the VGA/DVI cable input signal is
active
-If power ON, U108 #1 (LED_GREEN) will send out low potential, and then LED GREEN on.
-If power saveing, U108 #48 (LED_Amber) will send out low potential, and then LED Amber on.
-If power ON or power saveing, when press power key, U108 #9 receives low pulse, then U108 will be
sleeping and turn off backlight, at the same time, the panel will lose +5V.
The Panel_Vcc, Backlight_En, CLK/DATA output to panel will follow the following sequency.

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Power supply for panel+5V VDD
90% 90%
10%
0V 10%
T1 T2
T5 T6 T7
Signals Valid data
(Digital RGB, HS, VS, DE, CLOCK)
0V
T3 T4
Power supply for backlight
T1(ms)
T2 (ms)
T3 (ms)
T4 (ms)
T5 (ms)
T6 (ms)
T7(ms)
SPEC(CMO)
0.5 ~10
0.0~50
≥450
≥90
0.0~50
NA
>500
5. D-SUB Connector Pin Assignment
6. AC Outlet Pin Assignment
Pin
Symbol
1
Line
2
GND
3
Neutral
7. Inner Connector Pin Assignment
7.1 CN103 (Connect M/B to Panel,)
Pin
Symbol
Description
1
Panel_Vcc
Panel power supply (typ.5.0V)
2
Panel_Vcc
Panel power supply (typ. 5.0V)
3
Panel_Vcc
Panel power supply (typ. 5.0V)
4
NC
5
NC
6
NC
Pin
Symbol
Pin
Symbol
Pin
Symbol
1
Red
6
Red_GND
11
GND
2
Green
7
Green_GND
12
DDC_SDA
3
Blue
8
Blue_GND
13
Hsync
4
GND
9
PC+5V
14
Vsync
5
Cable Detect
10
GND
15
DDC_SCL

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7
GND_LVDS
LVDS Ground
8
RXE3+
LVDS signal of even channel 3(-)
9
RXE3-
LVDS signal of even channel 3(+)
10
RXEC+
LVDS signal of even channel clock (+)
11
RXEC-
LVDS signal of even channel clock (-)
12
RXE2+
LVDS signal of even channel 2(+)
13
RXE2-
LVDS signal of even channel 2(-)
14
GND_LVDS
LVDS Ground
15
RXE1+
LVDS signal of even channel 1(+)
16
RXE1-
LVDS signal of even channel 1(-)
17
GND_LVDS
LVDS Ground
18
RXE0+
LVDS signal of odd channel 0(+)
19
RXE0-
LVDS signal of odd channel 0(-)
20
RXO3+
LVDS signal of odd channel 3(+)
21
RXO3-
LVDS signal of odd channel 3(-)
22
RXOC+
LVDS signal of even channel clock (+)
23
RXOC-
LVDS signal of even channel clock (-)
24
GND_LVDS
LVDS Ground
25
RXO2+
LVDS signal of even channel 2(+)
26
RXO2-
LVDS signal of even channel 2(-)
27
RXO1+
LVDS signal of even channel 1(+)
28
RXO1-
LVDS signal of even channel 1(-)
29
RXO0+
LVDS signal of odd channel 0(+)
30
RXO0-
LVDS signal of odd channel 0(-)
7.2 CN1, CN2, CN3, CN4 (Connect to Panel Backlight,)
Pin
Symbol
Description
1
HV
High voltage for lamp
2
LV
Low voltage for lamp
7.3 CN104 (Connect to keypad, WAFER2*4P or compatible connector)
Pin
Symbol
Description
1
SELECT
OSD “input source Select” control
2
MENU
OSD “MENU” control
3
MINUS
OSD “-” control and “Auto adjust” adjustable hot key
4
PLUS
OSD “+” control and “Brightness/Contrast” adjustable hot key
5
LED Green
LED Green on/off control
6
GND
Ground
7
LED Amber
LED amber on/off control
8
POWER
Ground

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8. Key Parts Pin Assignments
U105(RTD2545LH)