Dell U4021QW User manual

Version: 01
Date: 2021/10/30
Service Manual - U4021QW

Product Announcement:
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.
Qualified Repairability:
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.
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 away from water or
expose in extremely high humility environment.
! To ensure the continued reliability of this
product, use only original manufacturer’s
specified parts.
! To ensure following safety repairing behavior, put
the replaced part on the components side of
PWBA, not solder side.
! 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.
! The fusion point of Lead-Free solder requested in
the degree of 220°C.
1. Important Safety Notice

2. Exploded view diagram with list of items
NOTE:
For replacement of power cord, connectivity cable and external power supply (if applicable), contact Dell:
1. Go to https://www.dell.com/support.
2. Verify your country or region in the Choose A Country/Region drop-down menu at the bottom-right corner of the page.
3. Click Contact Us next to the country dropdown.
4. Select the appropriate service 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
13
4 1
15
6
Speaker
1
1 7
8 1
9
12
13 1
114
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
Power cable
ASSY BASE
ASSY Middle Frame
119 See “NOTE”
Thunderbolt™ 4 (USB Type-C) Active cable
HDMI cable
DisplayPort cable
Joystick BD
10 1
11
Main bracket ASSY
1
Rear Cover
17
16 18
15
19

3. Wiring Connectivity Diagram

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:
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
- Penknife
- 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
Remove the monitor stand base:
1. Place the monitor on a soft cloth or cushion.
2. Press and hold the stand-release button.
3. Lift the stand up and away from the monitor.
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.
Use a Philips-head screwdriver to remove 4pcs
screws for unlocking mechanisms.
(No.1~4 screw size=M4x11; Torque=11±1kgfxcm)
23
41
5
2
13
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-head screwdriver to remove 2pcs
screw for unlocking the joystick board, then release
the joystick board by tear off the tapes.
(No.1~2 screw size=M2x2.4, Torque=1±0.2kgfxcm)
1
2
Use a Philips-head screwdriver to remove 8pcs
screws for unlocking the speakers with middle bezel.
Release the speakers’ cables from the hooks of the
middle bezel, and then disconnect the speaker cable
away from the connector of the circuit board.
(No.1~8 screw size=M3x8, Torque=5±0.5kgfxcm)
S7
Disconnect the FFC cable and EDP cable away from
the connectors of the board. Use a Philips-head
screwdriver to remove 1pcs screw for unlocking the
USB board, then release the USB board from hooks.
(No.1 screw size=M3x6, Torque=5±0.5kgfxcm)
S6
1
2
6
7
8
53
4
1
S5

5. Disassembly and Assembly Procedures
S10
Put the middle bezel with LED board on a cushion,
and then release the cable by tearing off the tapes.
Tear off 1pcs mylar tape on the LED board, then
release the LED board from the pins of the middle
bezel.
Remove the two speakers U. se a Philips-head
screwdriver to remove 21pcs screws for unlocking
the middle bezel, then disconnect the LED cable
away from the board, and then remove the bezel.
(No.1~21 Screw size= M3x5, Torque=5±0.5kgfxcm)
S8
1
4
16
14
15
3
6
10
11
12
20
19
18
21 56
2
78
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-head
screwdriver
(No.1~7 Screw size= M3x5, Torque=5±0.5kgfxcm)
S9
S11
Lift up the bracket chassis, and tear of the tape 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.
4
2
3
1
6
5
7

5. Disassembly and Assembly Procedures
Use a Philips-head screwdriver to remove
screws for unlocking power board, interface board
and LED driver board.
8pcs
(No.1 screw size=M4x8, Torque=6±0.5kgfxcm;
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 .
41
3
2
7
6
58
S13

5. Disassembly and Assembly Procedures
5.2 Assembly Procedures:
Place a bracket chassis base on a protective
cushion, then stick 3pcs Silicon sheets on the
position as the picture below shown.
S2
S1
S4
S3
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. Provide the power source to the panel
module to make sure the panel can be powered on.
S5
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 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 into the bracket. Take 1pcs LED driver board
to connect with the power board, turn over the board
and locate it into the bracket. Use a Philips-head
screwdriver to tighten 8pcs screws for locking the
interface board, power board and LED driver board.
(No.1 screw size=M4x8, Torque=7.5±0.5kgfxcm;
No.2~8 screw size=M4x8, Torque=7.5±0.5kgfxcm)
41
3
2
7
6
58
Take a black mylar to insert the hooks of the bracket
to cover the power board.