Dell U4323QE User manual

Version: 01
Date: 2022/07/22
Service Manual - U4323QE

! To prevent the product away from water or
expose in extremely high humility environment.
This product is certificated to meet RoHS
Directive and Lead-Free produced definition.
Using approved critical components only is
recommended when the situation to replace
defective parts. Vender assumes no liability
express or implied, arising out of any unauthorized
modification of design or replacing non-RoHS
parts. Service providers assume all liability.
Product Announcement:
Proper service and repair is important to the safe,
reliable operation of all series products. The
service providers recommended by vender should
be aware of notices listed in this service manual in
order to minimize the risk of personal injury when
perform service procedures. Furthermore, the
possible existed improper repairing method may
damage equipment or products. It is recommended
that service engineers should have repairing
knowledge, experience, as well as appropriate
product training per new model before performing
the service procedures.
Qualified Repairability:
NOTICE:
! To avoid electrical shocks, the products should be
connected to an authorized power cord, and turn
off the master power switch each time before
removing the AC power cord.
! To ensure following safety repairing behavior, put
the replaced part on the components side of
PWBA, not solder side.
! To ensure the continued reliability of this
product, use only original manufacturer’s
specified parts.
! The fusion point of Lead-Free solder requested in
the degree of 220°C.
! To ensure using a proper screwdriver, follow the
torque and force listed in assembly and
disassembly procedures to unscrew screws.
! Using Lead-Free solder to well mounted the
parts.
1. Important Safety Notice

2. Exploded view diagram with list of items
2. Verify your country or region in the Choose A Country/Region drop-down menu at the bottom-right corner of the page.
NOTE:
5. Choose the method of contacting Dell that is convenient for you.
For replacement of power cord, connectivity cable and external power supply (if applicable), contact Dell:
3. Click Contact Us next to the country dropdown.
1. Go to https://www.dell.com/support.
4. Select the appropriate service or support link based on your need.
ItemDescriptionQ'tyRemark
11
ForEMEAOnly,notfor
otherregions
21
13
41
15
6Speaker 1
1
7
81
9
12
131
114
Power BD
Panel
Interface BD
QAP
1
1
Stand Base ASSY
See “NOTE”
See “NOTE”
See “NOTE”
See “NOTE”
USB_C Gen2 1.0 M cable(A to C)
Power cable
ASSY Middle Frame
See “NOTE”
Premium High Speed HDMI 1.8 M cable
DisplayPort 1.8 cable
10 1
11
Main bracket ASSY
1
Rear Cover
12
11 13
10
14
USB_C Gen2 PD 3.0 1.0 M cable(A to C)

3. Wiring Connectivity Diagram
LED BD
Speaker
USB BD
Interface board
43 inch LCD panel

4. How to connect and disconnect power cable/ connectivity cable
WARNING: To change power cable/ connectivity cable, switch off power before unplugging the cable and replugging in required
cable.

4. How to connect and disconnect power cable/ connectivity cable

5. Disassembly and Assembly Procedures
5.1 Disassembly Procedures:
Tool Required:
- Penknife
List the type and size of the tools that would typically can be
used to disassemble the product to a point where components
and materials requiring selective treatment can be removed.
Tool Description:
- Screwdriver(Phillip head) #1
- Screwdriver(Phillip head) #2
- Soldering iron and absorber
NOTE:
This “Disassembly and Assembly Procedures” is for EMEA only,
not for other regions. Please note that Dell will deem warranty void
if any disassembly is done on the monitors.
S2
S1
S3
3. Lift the stand up and away from the monitor.
Remove the monitor stand base:
1. Place the monitor on a soft cloth or cushion.
2. Press and hold the stand-release button.
Wedge your fingers between the rear cover and the
middle bezel on the corners of the top side of the
monitor to release the rear cover, then use one hand
to press the middle bezel, the other hand to pull up
carefully the rear cover in order of arrow preference
for unlocking mechanisms of rear cover.
screws for unlocking mechanisms.
Use a Philips-head screwdriver to remove 4pcs
(No.1~4 screw size=M4x11; Torque=11±1kgfxcm)
23
41
1
2
3
4
Lift the rear cover up carefully. Disconnect the
joystick key cable from the connector of the interface
board, and then remove the rear cover and put it
aside for later disassembling
(No.1~2 screw size=M2x2.4,Torque=1±0.2kgfxcm)
Use a Philips-head screwdriver to remove 2pcs
screw for unlocking the joystick board, then tear off
the tapes and release the joystick board.
Use a Philips-head screwdriver to remove 7pcs
screws for unlocking the two speakers. Release the
left speaker cables from the probers of the middle
frame, and then disconnect the speaker cable, LED
cable and USB cable away from the connector.
(No.1~7 screw size=M3x8, Torque=4±1kgfxcm)
S5
14
6
5
74
S4
S6

5. Disassembly and Assembly Procedures
3
2
1
S12
S11
S10
(No.1~4 screw size=M3x4, Torque=3.5±0.5kgfxcm)
Use a Philips-head screwdriver to remove 4pcs
screw for unlocking the USB unit with the middle
frame, and then release the USB unit from the hooks
of middle frame.
3
2
1
4
Use a Philips-head screwdriver to remove 2pcs
screws for unlocking the USB cover, remove the USB
cover, then use a Philips-head screwdriver to remove
1pcs screw for locking the USB board with the USB
bracket. Disconnect the USB connective cable.
No.2~3 screw size=M3x4, Torque=1±0.2kgfxcm)
(No.1 screw size=M3x3, Torque=3.5±0.5kgfxcm;
3
2
1
Release the speakers’ cable to from the hooks of the
middle frame, then remove the speakers.
1
2
7
8
9
13
14
15
3456
10
11
12
21
20
19 18 17 16
22
23
24
25
26
28 27
Tear off 1pcs aluminum foil to release the bracket
chassis. Use a Philips-head screwdriver to remove
28pcs screws for unlocking the middle frame with the
panel module.
(No.1~28 Screw size= M3x0.5x4, Torque=5±0.5kgfxcm)
S7
S8
S9
Tear off 3pcs aluminum foil, then use a Philips-head
screwdriver to remove 4pcs screws for locking the
bracket chassis module with the panel.
(No.1~4 Screw size= M6x12, Torque=9±0.5kgfxcm)
Lift up the bracket chassis, and disconnect the LVDS
cable from the connector of the T-CON board of
panel module, then put the bracket chassis on a
protective cushion for later disassembling.
23
4
1

5. Disassembly and Assembly Procedures
No.2~8 screw size=M3x7.5, Torque=6±0.5kgfxcm)
Use a Philips-head screwdriver to remove 9pcs
screws for unlocking power board and interface
board with the bracket.
(No.1 screw size=M4x8, Torque=6±0.5kgfxcm;
Remove the circuit boards from the bracket
chassis module carefully, and then disconnect all
of the cables.
S16
S17
5
7
6
824
13
(No.1~2 Screw size= M3x0.5x4, Torque=3~5kgfxcm)
Tear off 4pcs rubbers , then use a Philips-head
screwdriver to remove 2pcs screws for unlocking the
small bracket with T-Con board, then remove the
small bracket, then release the LED key cable by
tearing off tapes on the back of the cable.
S13
Lift up the middle frame and put it into a fixture, tear
off the maylar tape for releasing the LED key board
away from the middle frame.
S14
1
2
Remove 2pcs shading tape on the left and right side
of the panel corner, then remove 27pcs acetate
tapes on the specific positions of the back of panel.
S15

5. Disassembly and Assembly Procedures
Put 1pcs power board into the bracket, then use a
Philips-head screwdriver to tighten 4pcs screws for
locking the power board.
(No.1 screw size=M4x8, Torque=6±0.5kgfxcm;
No.2~4 screw size=M3x7.5, Torque=6±0.5kgfxcm)
Place a bracket chassis base on a protective
cushion, then stick 5pcs Silicon sheets on the
position as the picture below shown.
5.2 Assembly Procedures:
S2
S1
S4
(No.6~9 screw size=M3x7.5, Torque=6±0.5kgfxcm)
Take 1pcs interface board, connect a LVDS cable to
the connector of the interface board, then connect
the power connective cables to the interface board.
Turn over the interface board and locate it into the
bracket. Use a Philips-head screwdriver to tighten
4pcs screws for locking the interface board.
S3
5
7
Panel preparation: Take out 1pcs panel module from
the carton, remove the protective film by tearing off
all the tapes of screen and four sides, then examine
the panel surface according to inspection criteria
carefully.
S5
24
13
6
8
Take 1pcs Dell nameplate, then use a locating fixture
to fix the nameplate to the front bezel of the module,
and then move the whole unit into a laminating
fixture, use the laminating fixture to press the
nameplate with the bottom side of the panel module
firmly attachment.
S6
Turn over the panel module to place screen faced
down. Paste 2pcs shading tape on the left and right
side of the panel corner, then paste 27pcs acetate
tapes on the specific position of the back of panel as
the picture below shown.

5. Disassembly and Assembly Procedures
Take 1pcs LED board and 1pcs middle frame, and
then locate the LED board into the specific position of
the middle frame Paste 1pcs mylar tape to fix the .
LED board with middle frame, then thread the cable
through the hole of the middle frame.
Use a Philips-head screwdriver to tighten 4pcs
screws for locking the bracket with the panel, then
connect the panel lamp cable to the connectors of
the board and fix the LVDS connector, T-con
connector and bracket with 3pcs aluminum foil.
(No.1~4 Screw size= M6x12, Torque=9±0.5kgfxcm)
23
4
1
Take 1pcs T-Con cover to assemble with T-Con
board, then use a Philips-head screwdriver to tighten
2pcs screws for locking the cover with T-Con board.
Paste 4pc black rubbers on the T-Con cover and
panel as the picture below shown.
(No.1~2 Screw size= M3x0.5x4, Torque=3~5kgfxcm)
S8
Move the bracket chassis module close to the panel
module, then connect the LVDS cable to the
connector of the T-Con board, then put the bracket
on the back of the panel module.
S9
S10
S11
S12
S7
Assemble the middle frame with the panel unit, then
tear off 3pcs adhesive tape papers on the back of
cable and fix the LED cable on the middle frame as
the picture below shown.
1
2
Use a Philips-head screwdriver to tighten 28pcs
screws for locking the middle frame with the panel.
Paste 1pcs aluminum foil to fix the bracket chassis.
(No.1~28 Screw size= M3x0.5x4, Torque=5±0.5kgfxcm)
1
2
7
8
9
13
14
15
3456
10
11
12
21
20
19 18 17 16
22
23
24
25
26
28 27
Take a pair of speakers, locate the left speakers to
the probers of the middle frame, then locate the
speakers’ cable to the hooks of the middle frame.
S13

5. Disassembly and Assembly Procedures
S16
S14
S17
(No.1 screw size=M3x3, Torque=3.5±0.5kgfxcm;
No.2~3 screw size=M3x4, Torque=1±0.2kgfxcm)
Take 1pcs USB board, 1pcs USB connective cable
and 1pcs USB bracket. Connect the USB cable to
the connector of the USB board, and then locate the
USB board into the USB bracket and use a
Philips-head screwdriver to tighten 1pcs screw for
locking the USB board with the bracket. Take 1pcs
USB hub cover to assemble with the USB bracket,
then use a Philips-head screwdriver to tighten 2pcs
screws for locking the cover with the whole unit.
(No.1~7 screw size=M3x6, Torque=4±1kgfxcm)
Locate the right speakers into the provers of the
middle frame, then connect the LED cable, USB
connective cable and speaker’s cable to the
connectors of the board. Use a Philips-head
screwdriver to tighten 7pcs screws for locking the
two speakers with middle frame.
1
3
2
(No.1~4 screw size=M3x4, Torque=3.5±0.5kgfxcm)
Locate the USB unit to the hooks of middle frame,
then use a Philips-head screwdriver to tighten 4pcs
screw for locking the USB unit with the middle frame.
S15
3
2
1
4
3
2
1
6
5
74
Take 1pcs joystick key, 1pcs joystick board and 1pcs
rear cover, then assemble the joystick key with the
board, then paste 1pcs conductive foam on the back of
the board. Locate the joystick board to the correct
position of the rear cover, then use a Philips-head
screwdriver to lock 2pcs screws for locking the joystick
board with rear cover. Tear off the papers on the back
of the cable, and then fix the joystick cable with tapes.
(No.1~2 screw size=M2x2.4,Torque=1±0.2kgfxcm)
12

5. Disassembly and Assembly Procedures
Take a stand base close to the monitor. Fit the two
tabs on the upper part of the stand into the grooves
on the back of the monitor, and then lower the stand
so that the monitor mounting area snaps onto the
stand.
Use a protective bag to pack the stand base, then lift
up the monitor to checking the gap between the front
bezel with panel module , then provide power supply
and a video signal to the monitor, then turn on the
monitor for functionality check.
S19
S20
S21
(No.1~4 screw size=M6x12; Torque=9±0.5kgfxcm)
Use a Philips-head screwdriver to tighten four
screws for locking mechanisms. Paste 1pcs label on
the specific positions as the picture below shown.
S18
23
41
Move the assembled rear cover close to the
panel unit, then connect the joystick key cable to
the connector of interface board. Put down the
rear cover and push the rear cover on the
positions marked as the picture below shown for
mechanisms engagement.

6. Trouble Shooting Instructions
Troubleshooting
WARNING: Before you begin any of the procedures in this section, follow
the Safety instructions.
Self-test
Your monitor provides a self-test feature that allows you to check whether your
monitor is functioning properly. If your monitor and computer are properly connected
but the monitor screen remains dark, run the monitor self-test by performing the
following steps:
1. Turn o both your computer and the monitor.
2. Unplug the video cable from the back of the computer. To ensure proper Self-test
operation, remove all digital and the analog cables from the back of computer.
3. Turn on the monitor.
The oating dialog box should appear on-screen (against a black background), if the
monitor cannot sense a video signal and is working correctly. While in self-test mode,
the power LED remains white. Also, depending upon the selected input, one of the
dialogs shown below will continuously scroll through the screen.
No DP Cable
The display will go into Standby Mode in 4 minutes.
www.dell.com/U4323QE
or
No HDMI Cable
The display will go into Standby Mode in 4 minutes.
www.dell.com/U4323QE
or
No USB-C Cable
The display will go into Standby Mode in 4 minutes.
www.dell.com/U4323QE

6. Trouble Shooting Instructions
4. This box also appears during normal system operation if the video cable becomes
disconnected or damaged.
5. Turn o your monitor and reconnect the video cable; then turn on both your
computer and the monitor.
If your monitor screen remains blank after you use the previous procedure, check your
video controller and computer, because your monitor is functioning properly.
Built-in diagnostics
Your monitor has a built-in diagnostic tool that helps you determine if the screen
abnormality you are experiencing is an inherent problem with your monitor, or with your
computer and video card.
Display
PIP/PBP
Input Source
Color
USB
Brightness/Contrast
Exit
UltraSharp 43 Monitor
Menu
Audio
Personalize
Others
HDMI CEC
LCD Conditioning
Firmware
Reset Others
Factory Reset
Service Tag
O
12T105
CN073K0
ENERGY STAR®
DDC/CI On
O
Display Info Select
Self-Diagnostics Select
To R un the Built-in diagnostics:
1. Ensure that the screen is clean (no dust particles on the surface of the screen).
2. Select OSD items of Self-Diagnostics in Others feature.
3. Press the joystick button to start the diagnostics. A gray screen is displayed.
4. Observe if the screen has any defects or abnormalities.
5. Toggle the joystick once again until a red screen is displayed.
6. Observe if the screen has any defects or abnormalities.
7. Repeat steps 5 and 6 until the screen displays green, blue, black, and white
colors. Note any abnormalities or defects.
The test is complete when a text screen is displayed. To exit, toggle the joystick control
again.
If you do not detect any screen abnormalities upon using the built-in diagnostic tool,
the monitor is functioning properly. Check the video card and computer.

6. Trouble Shooting Instructions
Common problems
The following table contains general information about common monitor problems you
might encounter and the possible solutions:
Common
symptoms
What you
experience
Possible solutions
No Video/
Power LED o
No picture • Ensure that the video cable connecting the
monitor and the computer is properly connected
and secure.
• Verify that the power outlet is functioning
properly using any other electrical equipment.
• Ensure that the power button is depressed fully.
• Ensure that the correct input source is selected
in the menu.
No Video/
Power LED on
No picture or no
brightness
• Increase brightness and contrast controls via
OSD.
• Perform monitor self-test feature check.
• Check for bent or broken pins in the video cable
connector.
• Run the built-in diagnostics.
• Ensure that the correct input source is selected
in the menu.
Missing Pixels LCD screen has
spots
• Cycle power on-o.
• Pixel that is permanently o is a natural defect
that can occur in LCD technology.
• For more information on Dell Monitor Quality and
Pixel Policy, see Dell Support site at:
https://www.dell.com/pixelguidelines.
Stuck-on Pixels LCD screen has
bright spots
• Cycle power On-O.
• Pixel that is permanently o is a natural defect
that can occur in LCD technology.
• For more information on Dell Monitor Quality and
PixelPolicy, see Dell Support site at:
https://www.dell.com/pixelguidelines.
Brightness
Problems
Picture too dim
or too bright
• Reset the monitor to factory settings.
• Adjust brightness and contrast controls via OSD.
Safety Related
Issues
Visible signs of
smoke or sparks
• Do not perform any troubleshooting steps.
• Contact Dell immediately.

6. Trouble Shooting Instructions
Common
symptoms
What you
experience
Possible solutions
Intermittent
Problems
Monitor
malfunctions on
& o
• Ensure that the video cable connecting the
monitor to the computer is connected properly
and is secure.
• Reset the monitor to factory settings.
• Perform monitor self-test feature check to
determine if the intermittent problem occurs in
self-test mode.
Missing Color Picture missing
color
• Perform monitor self-test.
• Ensure that the video cable connecting the
monitor to the computer is connected properly
and is secure.
• Check for bent or broken pins in the video cable
connector.
Wrong Color Picture color
not good
• Try dierent Preset Modes in Color settings
OSD.
• Adjust R/G/B value under Custom Color in Color
menu OSD.
• Change the Input Color Format to RGB or
YCbCr in the Color settings OSD.
• Run the built-in diagnostics.
Image retention
from a static
image left on
the monitor for
a long period of
time
Faint shadow
from the static
image displayed
appears on the
screen
• Set the screen to turn o after a few minutes
of screen idle time. These can be adjusted in
Windows Power Options or Mac Energy Saver
setting.
• Alternatively, use a dynamically changing
screensaver.

6. Trouble Shooting Instructions
Product specic problems
Problem What you
experience
Possible solutions
Screen image is
too small
Image is
centered on
screen, but
does not ll
entire viewing
area
• Check the Aspect Ratio setting in the Display
menu OSD.
• Reset the monitor to factory settings.
Cannot adjust
the monitor
with the
buttons on the
front panel
OSD does not
appear on the
screen
• Turn o the monitor, unplug the monitor power
cable, plug it back, and then turn on the monitor.
No Input Signal
when user
controls are
pressed
No picture, the
LED light is
white
• Check the signal source. Ensure the computer
is not in the power saving mode by moving the
mouse or pressing any key on the keyboard.
• Check whether the signal cable is plugged
in properly. Connect the signal cable again, if
necessary.
• Reset the computer or video player.
The picture
does not ll the
entire screen
The picture
cannot ll the
height or width
of the screen
• Due to dierent video formats (aspect ratio) of
DVDs, the monitor may display in full screen.
• Run the built-in diagnostics.
No image
when using DP
connection to
the PC
Black screen • Verify which DP standard (DP 1.1a or DP 1.4) is
your Graphics Card certied to. Download and
install the latest graphics card driver.
• Some DP 1.1a graphics card cannot support
DP 1.4 monitors. Go to OSD menu, under Input
Source selection, press and hold DP select
joystick key for 8 seconds to change the monitor
setting from DP 1.4 to DP 1.1a.

6. Trouble Shooting Instructions
Problem What you
experience
Possible solutions
No image when
using USB-C
connection
to computer,
laptop, and so
on
Black screen • Verify if the USB-C interface of the device can
support DP alternate mode.
• Verify if the device required more than 90 W
power charging.
• USB-C interface of device cannot support DP
alternate mode.
• Set Windows to Projection mode.
• Ensure that the USB-C cable is not damaged.
No charging
when using
USB-C
connection
to computer,
laptop, and so
on
No charging • Verify if the device can support one of 5 V/9 V/
15 V/20 V charging proles.
• Verify if the Notebook requires a >90 W power
adaptor.
• If the Notebook requires a >90 W power
adaptor, it may not charge with the USB-C
connection.
• Ensure that you use only Dell approved adapter
or the adapter that comes with the product.
• Ensure that the USB-C cable is not damaged.
Intermittent
charging when
using USB-C
connection to
computer,
laptop, and so
on
Intermittent
charging
• Check if the maximum power consumption of
device is over 90 W.
• Ensure that you use only Dell approved adapter
or the adapter that comes with the product.
• Ensure that the USB-C cable is not damaged.
No image when
using USB-C
MST
Black screen or
nd
2 DUT is not
Prime mode
• USB-C input, Go to OSD menu, under Display
Info check the Link Rate is HBR2 or HBR3, if
Link Rate is HBR2, suggest to use USB-C to DP
cable to turn on MST.
No network
connection
Network
dropped or
Intermittent
• Do not toggle O/On the power button when
network is connected, keeps the power button
On.

6. Trouble Shooting Instructions
Problem What you
experience
Possible solutions
The LAN port is
not functioning
OS setting
or cable
connection
issue
• Ensure that the latest BIOS and drivers for your
computer are installed on your computer.
• Ensure that the RealTek Gigabit Ethernet
Controller is installed in the Windows Device
Manager.
• If your BIOS Setup has a LAN/GBE Enabled/
Disabled option, make sure it is set to Enabled.
• Ensure that the Ethernet cable is connected
securely on the monitor and the hub/router/
rewall.
• Check the status LED of the Ethernet cable to
conrm connectivity. Re-connect both ends of
the Ethernet cable if the LED is not lit.
• First power o the Computer and unplug the
Type-C cable and power cord of the monitor.
Then, power on the computer, plug in the
monitor power cord and Type-C cable.
Universal Serial Bus (USB) specic problems
Specic
symptoms
What you
experience
Possible solutions
USB interface is
not working
USB peripherals
are not working
• Check that your display is turned ON.
• Reconnect the upstream cable to your
computer.
• Reconnect the USB peripherals (downstream
connector).
• Turn o the monitor and turn it on again.
• Reboot the computer.
• Certain USB devices such as portable hard
drives require higher power source; connect the
drive to the computer directly.