Dell U4021QW Service Manual Download Page 18

Page: 18 / 21

6. Trouble Shooting Instructions

Problem

What you
experience

Possible solutions

Black screen on
Chrome OS @
HDMI port

Black screen
after switch
on PBP mode
80/20

• Graphic Card Driver not able to support

resolution 4096 x 2160.

• Switch to PBP 75/25 or 50/50

No Display
or USB not
working

No Display
or USB not
working on
Windows 7

• Windows 7 not support. Switch to Windows 10.

Enter BIOS
setup menu @
HDMI port

Unable to goto
BIOS setup
menu

• unplug the HDMI cable or disconnect the

monitor

Black screen on
PBP mode @
HDMI

Switch to PBP
80/20 mode no
displayed image
@ HDMI when
connected to
Docking device

• Some docking device do not support 80/20

(4096 x 2160) resolution.

• Switch PBP mode to 75/25 or 50/50
• Plug/unplug HDMI cable
• Change input source to DP port

Display image at
5120 x 2160 @
30 Hz at HDMI
port

Not able to
select 5120
x 2160 @ 60
Hz in Graphic
Control Panel at
HDMI Port

• Due to legacy platform HDMI 2.0 HW bandwidth

limitation, it can only support 5120 x 2160 @ 30
Hz.

• Switch to DP 1.2 or higher

Monitor
displayed image
at 3840 x 2160
@ 60 Hz

Not able to
select 5120 x
2160 in Graphic
Control Panel

• Due to legacy platform HW limitation, it does not

support 5120 x 2160.

• To support 5120 x 2160 @ 60 Hz, check whether

the platform meet either one of the following:

DP1.2 or higher.

Type-C Alt Mode DP1.2 or higher.

HDMI 2.0.

Monitor displays
image at 3840
x 2160 @ 60 Hz
when using Intel
Graphic Card

Not able to
select 5120
x 2160 @ 60
Hz with: Intel
CPU Gen10 or
lower, and Intel
Graphic Driver
x.7584 onward.

• Intel Graphic Driver has disabled 5K Mode

Support from V7584 to 7916.

• Install/Re-install Intel Graphic driver after v.7925

or higher.

Monitor display
image at 5120 x
2160 @ 30Hz
when
connected to
Intel Graphic
Card via TBT
port

Not able to
select 5120
x 2160 @
60 Hz

• Due to legacy Intel CPU bandwidth limitation.
• Inte CPU 10th (Ice Lake) or Gen 11th (Tiger

Lake) or later CPU (DP 1.4) can support 5120 x
2160 @ 60 Hz.

Summary of Contents for U4021QW

Page 1: ...Version 01 Date 2021 10 30 Service Manual U4021QW ...

Page 2: ...ipment 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 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 prevent the product awa...

Page 3: ...or support link based on your need 5 Choose the method of contacting Dell that is convenient for you Item Description Q ty Remark 1 1 For EMEA Only not for other regions 2 Safety Mylar 1 1 3 4 1 1 5 6 Speaker 1 1 7 8 1 9 12 13 1 1 14 1 15 1 16 USB BD Panel Key BD LED driver BD Interface BD 1 1 17 1 1 Power BD ASSY 18 See NOTE See NOTE ASSY RISSER See NOTE See NOTE Super Speed USB 3 2 Gen1 A to B P...

Page 4: ...3 Wiring Connectivity Diagram ...

Page 5: ...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 ...

Page 6: ...4 How to connect and disconnect power cable connectivity cable ...

Page 7: ...up carefully the rear cover in order of arrow preference for unlocking mechanisms of rear cover Use a Philips head screwdriver to remove 4pcs screws for unlocking mechanisms No 1 4 screw size M4x11 Torque 11 1kgfxcm 2 3 4 1 5 2 1 3 4 S4 Lift the rear cover up carefully Disconnect the joystick cable away from the connector and tear off 1pcs aluminum foil and then remove the rear cover Use a Philips...

Page 8: ...e 5 0 5kgfxcm S8 1 4 16 14 15 3 6 10 11 12 20 19 18 21 5 6 2 7 8 9 13 17 Tear off 2pcs aluminum foil for releasing the panel lamp cable and then u U to remove 2pcs screws for unlocking the heat sink with the board Disconnect the lamp cable away from the connector of the board se a Philips head screwdriver to remove 5pcs screws for unlocking the bracket chassis module with the panel se a Philips he...

Page 9: ...5kgfxcm No 2 8 screw size M3x7 5 Torque 6 0 5kgfxcm Remove the LED driver board interface board abd power board from the disconnect all of the cables bracket chassis module carefully and then S14 S15 Tear off 2pcs shading tapes and then disconnect the panel lamp cable from the two connectors of the panel module S12 Remove the mylar tape from the hooks of the bracket 4 1 3 2 7 6 5 8 S13 ...

Page 10: ...ove the whole unit into a laminating fixture use the laminating fixture to press the nameplate with the front bezel of the panel module firmly attachment S6 Turn over a power board and put the power board into the bracket chassis Take 1pcs interface board connect 1pcs LVDS cable to the interface board then connect the power board to the interface board Turn over the interface board and locate it i...

Page 11: ...the lamp cable se a Philips head screwdriver to tighten 5pcs screws for locking the bracket chassis module with the panel No 1 7 Screw size M3x5 Torque 5 0 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 Connect the panel lamp cable to the connector of the board...

Page 12: ... of the cable and then fix the joystick cable with tapes No 1 2 screw size M2x2 4 Torque 1 0 2kgfxcm S14 2 6 7 8 5 3 4 1 Take 1pcs USB board 1pcs conductive foam 1pcs FFC cable and 1pcs EDP cable Connect the two cables to the connectors of the USB board then paste 1pcs conductive foam on the back of the USB board and then locate the USB board into the hooks of the middle bezel Connect the FFC and ...

Page 13: ...eo signal to the monitor then turn on the monitor for functionality check S17 S18 Use a Philips head screwdriver to tighten four screws for locking mechanisms Stick 1pcs label on the specific positions as the picture below shown No 1 4 screw size M4x11 Torque 11 1kgfxcm S16 2 3 4 1 Paste 1pcs aluminum foil to cover the connectors as the picture below shown then move the assembled rear cover close ...

Page 14: ...f 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 U4021QW or No HDMI 1 Cable The display will go into Standby Mode in 4 minutes www dell com U4021QW or No HDMI 2 Cable The display will go into Standby Mode in 4 minutes w...

Page 15: ...s 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 Common Problems The following table contains general information about common monitor problems you might encounter and the possible solu...

Page 16: ...on off 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 prop...

Page 17: ... picture cannot fill the height or width of the screen Due to different video formats aspect ratio of DVDs the monitor may display in full screen Run the built in diagnostics No Video or display on HDMI port No video when connecting docking dongle or Blu ray DVD players Due to legacy platform cannot recognize or output 5120 x 2160 we suggest to switch to lower resolution to cover this compatibilit...

Page 18: ...l Panel at HDMI Port Due to legacy platform HDMI 2 0 HW bandwidth limitation it can only support 5120 x 2160 30 Hz Switch to DP 1 2 or higher Monitor displayed image at 3840 x 2160 60 Hz Not able to select 5120 x 2160 in Graphic Control Panel Due to legacy platform HW limitation it does not support 5120 x 2160 To support 5120 x 2160 60 Hz check whether the platform meet either one of the following...

Page 19: ...Dell approved adapter or the adapter that comes with the product Ensure that the ThunderboltTM 4 USB Type C active cable is not damaged Intermittent charging when using ThunderboltTM 3 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 E...

Page 20: ...nderboltTM 4 USB Type C active cable and power cord of the monitor Then power on the computer plug in the monitor power cord and ThunderboltTM 4 USB Type C active cable Universal Serial Bus USB specific problems Specific What You Possible Solutions Symptoms Experience USB interface is USB peripherals Check that your display is turned ON not working are not working Ensure USB Selection is set corre...

Page 21: ... 3 0 USB 2 0 and USB 1 1 ports Ensure that the correct USB port is used Reconnect the upstream cable to your computer Reconnect the USB peripherals downstream connector Reboot the computer Wireless USB peripherals stop working when a USB 3 0 device is plugged in Wireless USB peripherals responding slowly or only working as the distance between itself and its receiver decreases Increase the distanc...

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