Dell E190Sf User manual

Service Manual
- 0 -
Service Manual
LCD Monitor E190Sf

1
Service Manual Versions and Revision
No. Version Release Date Revision
1 1.0 2009/02/16 Initial Release
Copyright
Copyright 2009 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 E190Sf Service Manual

Service Manual
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Table of Contents
CHAPTER 1- PRECAUTIONS & SAFETY NOTICES.....................................................................................................................0 H3
1. SAFETY PRECAUTIONS .................................................................................................................................................... 1 H3
2. PRODUCT SAFETY NOTICE.............................................................................................................................................. 2 H3
3. SERVICE NOTES.................................................................................................................................................................. 3 H3
CHAPTER 2- SERVICE TOOLS & EQUIPMENT REQUIRED .....................................................................................................4 H4
CHAPTER 3- CIRCUIT THEORY ......................................................................................................................................................5 H5
1. BLOCK DIAGRAM ................................................................................................................................................................... 6 H5
2. ELECTRONIC CIRCUIT THEORY ............................................................................................................................................... 7 H5
3. FACTORY PRESET TIMING TABLE ................................................................................................................................ 8 H11
4. POWER ON/OFF SEQUENCY .................................................................................................................................................. 9 H11
5. D-SUB CONNECTOR PIN ASSIGNMENT................................................................................................................................. 12
6. AC OUTLET PIN ASSIGNMENT .............................................................................................................................................. 12
7. INNER CONNECTOR PIN ASSIGNMENT................................................................................................................................... 10 H13
8. KEY PARTS PIN ASSIGNMENTS .............................................................................................................................................. 14
CHAPTER 4- DISASSEMBLY &ASSEMBLY.................................................................................................................................11 H18
1. EXPLODED DIAGRAM ........................................................................................................................................................... 12 H18
2. E190SF DISASSEMBLY BLOCK.............................................................................................................................................. 19
3. ASSEMBLY BLOCK ................................................................................................................................................................ 20
CHAPTER 5- TESTAND ADJUSTMENT........................................................................................................................................ 21
1. FUNCTION KEY DEFINITIONS ................................................................................................................................................ 13 H21
2. OSD CONTROL ...................................................................................................................................錯誤!尚未定義書籤。
3. FACTORY MODE INTRODUCTION........................................................................................................................................... 14 H22
4. BURN-IN PATTERN................................................................................................................................................................. 15 H22
5. AUTO COLOR BALANCE (AUTOMATICALLY CALIBRATE CHIP ADC PARAMETER BY USING CHIP INTERNAL DAC.)................ 16 H22
6. EDID (REWRITE EDID DATA TO EEPROM).........................................................................................................................17 H23
7. UPLOAD FIRMWARE TO MCU VIA VGA CABLE .................................................................................................................... 18 H23
8. AFTER REPAIR,TO ENSURE THE QUALITY YOU SHOULD DO THE FOLLOWING TEST AND ADJUSTMENT. ................................... 19 H25
CHAPTER 6- TROUBLE SHOOTING..............................................................................................................................................20 H25
1. COMMON ACKNOWLEDGE .................................................................................................................................................... 21 H25
2. NO POWER &POWER LED OFF............................................................................................................................................ 22 H26
3. POWER LED AMBER............................................................................................................................................................. 23 H26
4. BACKLIGHT CAN’T BE TURNED ON ........................................................................................................................................ 27
5. NO PICTURE &BACKLIGHT ON ............................................................................................................................................. 24 H29
6. AT 32-GRAY SCALE PATTERN,COLOR LOST IN SOME SCALE ................................................................................................... 29
7. DIAGNOSTIC TEST PAT T E R N .................................................................................................................................................. 29
CHAPTER 7- RECOMMENDED PART LIST ................................................................................................................................. 32
ATTACHMENT 1- BILLOF MATERIAL......................................................................................................................................... 25 H34
ATTACHMENT 2- SCHEMATIC.......................................................................................................................................................26 H44
ATTACHMENT 3- PCB LAYOUT..................................................................................................................................................... 54

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Chapter 1- PRECAUTIONS & SAFETY NOTICES
1. 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:
zThis 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.
zUse only the specified power cord that comes with this monitor.
zDo 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.
zDo not remove the monitor cabinet. There is high-voltage parts inside that may cause electric shock
to human bodies.
zStop using the monitor if the cabinet is damaged. Have it checked by a service technician.
zPut your monitor only in a lean, cool, dry environment. If it gets wet, unplug the power cable
immediately and consult your closed dealer.
zAlways 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.
zDo not place heavy objects on the monitor or power cord.
2. 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.
3. SERVICE NOTES
zWhen replacing parts on circuit boards, clamp the solder wires around terminals before soldering.
zKeep wires away from high voltage, high temperature components and sharp edges.
zKeep wires in their original position so as to reduce interference.
zAdjustment of this product please refers to the user’ manual.
zUse 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. Fox_VISP_Programmer
9. Fox_VEDID_Programmer

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Chapter 3- CIRCUIT THEORY
1. Block Diagram
This Block is comprised of interface board and switching power supplier board which is included by
inverter for CCFL
2. Electronic Circuit Theory
2.1 Inverter PWM circuit
2.1.1 Inverter Control circuit operations:(fig.2)
Fig.2
DC_5V through R1 and C1 will provide power for U1 on the pin2(VDDA),When the voltage at VDDA
is less than ~3.4V,the IC will enter the lockout mode. The IC will resume operation when the voltage at pin
VDDA exceeds an approximate 3.8V threshold.
Pin3(SEL) used to select appropriate drive topologies,connecting pin SEL to GED shows the IC in the
Snubber
&Schottky
+5V DC output
Brightness Control
Photocoupler
To Panel CCFL
Feedback
Control
AC Input
90V~264V
Power PWM
Control IC
Power
ON/OFF Control
Rectifier&
Filter
Circuit
Lamp2 Lamp1
To IF Board
Inverter
PWM IC
Snubber
&Schottky
Feedback
Transformer
MOSFET
Power
MOSFET
+12V DC output
Inverter Transformer
AC Line Filter

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push-pull configuration..
SSTCMP(pin14) applys the soft-start function and the loop compensation funtion.C5 at SSTCMP
compensates the feedback loop and provides good transient response to load changes.
When the IC is enabled,it starts from the strinking mode and the TIMER(pin8) is activated.During lamp
ignition,if the voltage at pin SSTCMP exceeds an approximate 2.0V threshold,the drive frequency will swith
from stinking frequency to the operation frequency, The striking frequency is determined by (R4& R5)
connected to Pin 4(RT1)and Pin5(RT). The operating frequency is determined just by R4.
Applying a voltage level greater than 2V from IF BD to pin6(PWM) can enable the IC,Once the
voltage less than ~1.0V for longer than 20ms will disable the IC.
Once the lamps are ignited and the voltage at pins ISEN1(pin9),ISEN2(pin10),OLP1(pin12),and
OLP2(pin13) all exseed approximately 0.8V,the IC enters the normal operation mode and the PWM
dimming control is actived. During start up, ISEN1 (pin9and pin10) senses the voltage on the transformer
secondary. If no current is sensed approximately 2 seconds, U1 shuts off. re used to limit current. C3 is used
to dump noise.
DRV1 and DRV2 of U1 are used to drive Q1. DRV1 and DRV2 are controlled by build-in PWM IC.
Q1 is switched which has two build-in IGBTs. The working principle of circuit of T1, the same to circuit of
Power.
The voltage signal on negative pole of D1 sensed through R7/R8 comes to Pin11 of U1 VSEN (Lamp
Current Detection & Control). The CCFL current is detected through R12/R21 and reaches a regulated value.
The CCFL current detected at resistor R12/R21 is converted to a voltage level and input to the ISEN1/2
Once the CCFLs are ignited and current is sensed through resistor R12/R21, performs the loop compensation
function. The voltage at IC pin12 controls the drive duty cycle of the power MOSFETs to regulate the CCFL
current.
2.1.2 Output Circuit and Protection Circuit operations:(fig.3)
Fig.3
The transformer (T1) secondary winding leakage inductance and output capacitance(C22) forms a
lower pass filter,which converts the square-wave driving signal into a sinusoidal output voltage signal for
CCFL.
The over-voltage protection feature is implemented by using an extermal capacitor devider(C20/C21) to
sense the output voltage.The divide-down voltage signal is sent to the IC Pin11(VSEN) ,thus regulating the
output voltage at the transformer secondary.
If a CCFL is removed, fails or damaged during normal operation, CCFL current is no longer sensed and
the voltage on ISEN1/ISEN2 drops. Once the voltage at the ISEN1/ISEN2 pin is less than the lamp” on”
threshold, the shutdown timer is activated. The IC maintains the output voltage for approximately
2-3seconds and once the timer reaches a threshold of approximately 3V, the IC will shutdown. To restart the
IC, either toggle the SST_CMP pin or recycle the power on the VDDA pin.

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2.2 Power PWM circuit operations
2.2.1) Block diagram:(fig.4)
Fig.4
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 and R851 are joined between two inputting main circuit to prevent
man from shock. L850 is used to filter low frequency noise. C850 and C851 are used to discharge the
noise that L850 produced. High frequency waves are damped by C852 .
EMI Filter Rectifier and
filter
Isolation power
transformer
Rectifier and filter
Inverter circuit
PWM controller Switching element
Feedback Isolation
Rectifier and filter
To IF connector

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2.2.3)High Voltage to Low Voltage Control Circuit:(fig.6)
L854
bead
C861
3300p/250V
.
.
.
T851
SPW-XXX
5
8
6
7
3
1
12
11
9
10
+
C854
100u/450V
+
C855
10u/50V
R853
0.2R
R869
0R68 2W
ZD881
OPEN
.
.
.
T850
SPW-119
5
8
6
7
3
1
12
11
9
10
Si g nal _GND
Q850
AP2764
2
13
D853
TVS-P6KE170A
C875
4700p/250V
CN852
CON8PIN
1
2
3
4
5
6
7
8
Gate
Isense
GND
FB
GND
VDD
NC
Vin
R880
82K 2W
D851
FR10-10-LF
Si g nal _GND
C860 OPEN
Signal_GND
I850
LTV817M
3
14
2
R855
10K
-+
D850
BL4-06
3
1
2
4
D852
SF10-04
Signal _GND
C872
100P/1KV
R856
10 1%
R849
220R
R848 20R
R842
20K
C847
Open
C849
1nF/50V NPO
Si g nal _GND
C848
100nF/50VX
C846
220pF/50V NPO D849
NC
Si g nal _GND
R846
100K/ 1%
CN852
CON8 PIN
1
8
3
4
5
6
7
2
Gate
HV
GND
FB
GND
VDD
NC
Isense
Signal_GND
R841
NC
Sig nal _GND
R843
20K
R847
NC
Sig nal _GND
Si g nal _GND
U850
LD7575
1
45
2
83
7
6
RT
GNDOUT
COMP
HVI sense
NC
Vcc
Fig.6

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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. R852 is a fuse resistor to protect the following circuit
when inrush current is too large.
U850 is a current-mode PWM controller with excellent power-saving opration,It features a
high-voltage current source to directly supply the startup current from bulk capacitor and further to provide
lossless startup circuit. Max start-up current for U850 is 100 uA, When current flow from the bulk
capacitor C854 through R843 and R842 gets to HV pin to start up U850, Meanwhile,the VCC supply
current is as low as 100 uA thus most of the HV current is utilized to change the VCC capacitor C855,
Whenever the Vcc voltage is higher than UVLO (16V),the GATE pin will output signal to drive the power
MOSFET(Q850), the high-voltage current source is off and the supply current is provided from the
auxiliary winding of the trasformer PIN5.
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, R856 and C855 ,will be supplied to U850 for normal
operating.
The typical current mode PWM controller feedbacks both current signal and voltage signal to close the
control loop and achieve ragulation.U850 detects the Q850 current from Isense pin which max voltage is
set as 0.85V, then the Q850 current can be calculated as:I peak=0.85V/R869,When the sense voltage
across the sense resistor R869, reaches the threshold voltage over 0.85V, the output GATE drive will be
turned off. R849 and C846 is used to avoid the Isen pin damaged by the negative turn-on spike.
The voltage feedback signal is provided from the TL431(I851) through the I850 to the COMP pin.When
the voltage on COMP pin is lower than 1.2V,the IC will turn off.
When Q850 is turned off, the main current flow will be consumed through D851, C875, R880, this will
prevent Q850 from being damaged under large current impulse and voltage spike.
RT pin is to program the switching frequency ,by connecting R846 to ground to set the switching frequency,f
=(65.0/R846)*100(KHz).
2.2.4) DC 12V and DC 5V Output Circuit and Feedback circuit:(fig.7)
+5V
DIM/ON/OFF
C871
0.1/50V
Q890
2N7000/NC
G
DS
R871
270k
C890
0.1uF/50V/NC
R891
10K/NC
R867
270
+
C863
470u/25V
F85 1
5A/125V
R899 OPEN
+
C899
OPEN
+
C869
470u/25V
L851
CHK- 0 53
CN851
SIP-8P
6
1
2
5
3
4
7
8
+5V
+5V
GND
GND
DIM
ENA
PID
P-saving _on/off
Q851
2N4401/NC
E
B
C
C866
1000p/1KV
+12V
C876
0.1/50V
R866
10R 2W
L852
CHK - 05 3
I851
TL431
3
1
2
R862
10R 2W
R860
3K3 1%
R861
3K65 1%
D856 SR5-10
+
C868
470u/25V
R859
10K 1%
R858
5K1 1%
D855
NC/SF5-20
R886
10K/NC
C862
1000p/1KV
D854
SF5-20
D857 SR5-10
+
C867
470u/25V
C859
0.01/50V
R890
9.1K/NC
R887
10K/NC
+
C864
470u/25V
PID
R888
510R 2W/NC
ZD880
GDZ14B/NC
Fig.7