TCL 408 User manual

Service Manual TCL Communication Technology Holdings Ltd.
Rev.: 1.0
TCL 408_T507D1_Service Manual V1.0
Page: 1/30
Confidential and proprietary information contained in this repair guide is subject to change without notice.
Distribution, transfer, copy of any content or data in this document without the written permission of TCL is strictly prohibited.
TCL 408
T507D1
Warning:
➢All features, functions, specifications, and other product information provided in this document,
including but not limited to the advantages, aesthetics, price, components, performance, availability
and capacity of the product are subject to change without notice.
➢TCL will not be responsible for any damage to the product, injury or other safety issues caused by the
result of repair by an unauthorized service provider, user repair or unprofessional product repair.
➢Any damage to the product resulted from an attempt to repair the product by any person or 3rd party
other than TCL authorized service provider will not be covered by warranty.

Service Manual TCL Communication Technology Holdings Ltd.
Rev.: 1.0
TCL 408_T507D1_Service Manual V1.0
Page: 2/30
Confidential and proprietary information contained in this repair guide is subject to change without notice.
Distribution, transfer, copy of any content or data in this document without the written permission of TCL is strictly prohibited.
Content
1Precautions..............................................................................................................................................3
2General Product Information.................................................................................................................4
3Maintenance preparation .......................................................................................................................5
3.1 Handset with at least 50% battery charges................................................................................... 5
3.2 Supported Micro SD card and SIM card, 5V2A Charger, Type C 2.0 Cable................................. 5
3.3 PC with below configurations to do software update by using PC tool......................................... 5
3.4 Backup the user data before repairing. There are two ways below for your reference................. 5
4Factory Reset ..........................................................................................................................................6
4.1 Remove Google account before doing factory reset..................................................................... 6
4.2 Factory Reset................................................................................................................................. 6
4.3 Recovery mode.............................................................................................................................. 6
5Software Update......................................................................................................................................8
5.1 Software update by FOTA.............................................................................................................. 8
5.2 Software update by using Mobile Upgrade tool............................................................................. 8
6Function Test with Support Centre.....................................................................................................11
7Troubleshooting....................................................................................................................................13
7.1 What should I do if my device reboots by itself? ......................................................................... 13
7.2 What should I do if my device system lags or freezes? .............................................................. 13
7.3 What should I do if my device cannot charge or charges slowly?............................................... 13
7.4 What should I do if my device’s battery drains under normal use?............................................. 14
7.5 What should I do if my device auto powers off?.......................................................................... 14
7.6 What can I do if my device heats up?.......................................................................................... 14
7.7 What should I do if my device cannot power on?........................................................................ 15
8Contact of TCL hotline and service centers ......................................................................................15
9Disassembly and reassembly..............................................................................................................16
9.1 Disassembly tools........................................................................................................................ 16
9.2 Disassembly Process................................................................................................................... 16
9.3 Reassembly process and tools.................................................................................................... 23
10 Explode View.........................................................................................................................................27
11 Split View ...............................................................................................................................................28

Service Manual TCL Communication Technology Holdings Ltd.
Rev.: 1.0
TCL 408_T507D1_Service Manual V1.0
Page: 3/30
Confidential and proprietary information contained in this repair guide is subject to change without notice.
Distribution, transfer, copy of any content or data in this document without the written permission of TCL is strictly prohibited.
1 Precautions
1) Use only demagnetized tools specifically designed for small electronic repairs, most electronic
parts are sensitive to electromagnetic forces.
2) Use only high quality screwdrivers when repairing products. Poor quality screwdrivers can easily
damage the heads of the screws.
3) Always use genuine spare parts. Parts from third party may not function properly or even cause
damage.
4) The parts below require calibration to ensure proper function after repair, please contact TCL
authorized Repair Center.
Sensors (proximity, fingerprint), dual camera, touch screen panel, speaker, motherboard and more.
5) The IPXX degree of protection cannot be guaranteed in the event of repair by the user or by an
unqualified person.
6) If the device suffered from water/liquid damage, you will have the option to have a repair, but this
may exceed the value of the device, depending on level of damage.
7) If you need detailed diagnosis, please contact TCL authorized Repair Center.
8) Do not remove, damage, heat, short circuit, or disassemble the battery. If you need to replace the
battery, camera, screen or motherboard, go to a TCL authorized Repair Center for repair.
9) Before any repair, backup personal information and important data, and then proceed with the
repair.
10) Many semiconductors parts inside the device are sensitive to electrostatic discharges that can
cause unrecoverable damages on the parts. Setup and stay in an Electrostatic Protected Area
(EPA) to avoid electrostatic discharge before opening the device for repair.
11) Before repairing the device, you must be absolutely certain that the device is turned off.
12) Repair the device in a safe/explosion-proof environment. If the device is damaged, emits smoke or
if you smell a burning odor, stop repairing/using the device immediately, use a fire extinguisher or
fire-proof box, and contact TCL.
13) When removing the back cover, be careful not to damage the product, especially the battery.
Recommended safety equipment: Glasses/Gloves/Mask, etc.
14) Before assembly, make sure that there are no screws or foreign objects around the battery.
15) Before assembly, make sure that there are no abnormalities before reattaching the back cover.

Service Manual TCL Communication Technology Holdings Ltd.
Rev.: 1.0
TCL 408_T507D1_Service Manual V1.0
Page: 4/30
Confidential and proprietary information contained in this repair guide is subject to change without notice.
Distribution, transfer, copy of any content or data in this document without the written permission of TCL is strictly prohibited.
2 General Product Information
Features/Hardware
Description
Design
Dimensions: 164.66x75.4x8.99mm; Weight: 190g
System
Android 12
Processor
Chipset: G25 (MT6762V/CB); CPU: 4xCortex-A53 @2.0GHz+4xCortex-A53 @1.5GHz;
GPU: IMG GE8320 650MHz
Memory & Storage
4GB RAM +64GBROM; Support micro SD cards up to 512GB
Display
6.6" , TFT-IPS
Rear Camera
50 MP rear camera: PDAF, 1/2.55", 0.7um, F1.8, field of view 79.4°, 5P lens.
2 MP depth camera: FF, 1/5 '', 1.75μm, F2.4, field of view 88.8°, 3P lens
Front Camera
8MP front camera: FF, 1/4 '', 1.12μm, F2.0, field of view 77.5°, 4P lens
Battery
5000mAh (standard) Li-ion
Connectivity
2G bands: 850/900/1800/1900
3G bands: B1/2/5/8
4G bands: B1/3/5/7/8/20/28
802.11 a/b/g/n/ac Wi-Fi
Wi-Fi Direct
Mobile hotspot
Bluetooth 5.1, Type-C Cable
Dual SIM+T-Flash card
Sensors
GPS: support BDS/GPS/Glonass/Galileo,with A-GPS
Accelerometer, proximity sensor
Accessories
5V2A Charger, Type C 2.0 Cable, Quick Guide / PSI

Service Manual TCL Communication Technology Holdings Ltd.
Rev.: 1.0
TCL 408_T507D1_Service Manual V1.0
Page: 5/30
Confidential and proprietary information contained in this repair guide is subject to change without notice.
Distribution, transfer, copy of any content or data in this document without the written permission of TCL is strictly prohibited.
3 Maintenance preparation
3.1 Handset with at least 50% battery charges
3.2 Supported Micro SD card and SIM card, 5V2A Charger, Type C 2.0 Cable
3.3 PC with below configurations to do software update by using PC tool.
⚫CPU: Equal to Pentium 1.6 GHZ or above
⚫RAM: 4GB or above
⚫Hard Disk: 10GB or above
⚫Operation System: Win7/Win8/Win10
⚫USB port
⚫Internet connection with minimum internet speed of 8Mb/s
3.4 Backup the user data before repairing. There are two ways below for your
reference.
Method 1: You need to add your Google account details first. Go to “Settings”-> “System”-> “Backup” ->
Touch “Turn on” in the window which has now opened ->Touch “Back up now.
*App data, SMS text messages, Device settings, Call history, and Contacts will be backed up.
Method 2: You can back up your data to another phone via the “Switch Phone” app, and then recover
data when your phone has been repaired.
Swipe up in the home screen to find the search bar->enter “Switch Phone” ->Transfer the contents by
following the instructions.

Service Manual TCL Communication Technology Holdings Ltd.
Rev.: 1.0
TCL 408_T507D1_Service Manual V1.0
Page: 6/30
Confidential and proprietary information contained in this repair guide is subject to change without notice.
Distribution, transfer, copy of any content or data in this document without the written permission of TCL is strictly prohibited.
4 Factory Reset
Factory reset will reset your phone to restore it to its factory settings. This will delete all data including
files and downloaded apps. Please backup the user data before doing factory reset.
4.1 Remove Google account before doing factory reset
If Google account is not removed before doing the factory reset, it is not possible to setup the device
with another Google account at initial setup after the factory reset and it will require you to login your
previous signed-in Google account. It is recommended that you log out of the Google account. Follow
the below steps to remove your Google account from the device.
You can go to “Settings”-> “Accounts”->touch your google account-> “REMOVE ACCOUNT”->touch
“REMOVE ACCOUNT”.
4.2 Factory Reset
You can follow the below steps to perform factory reset when the phone is powered on.
Go to main menu -> “Settings”-> “System”-> “Reset”->“Erase all data (factory reset)”->Touch “Erase all
data” in the open window ->“Erase all data”.
4.3 Recovery mode
How to use: Long press “Power” Key + “Volume up” key in power off mode to enter recovery mode.
When to use: When you cannot start your handset or when there is something wrong during switch on
or when cannot charge.
Consumer personal data format: It will format consumer data, and the memory and settings of your
product will return as released from factory.

Service Manual TCL Communication Technology Holdings Ltd.
Rev.: 1.0
TCL 408_T507D1_Service Manual V1.0
Page: 7/30
Confidential and proprietary information contained in this repair guide is subject to change without notice.
Distribution, transfer, copy of any content or data in this document without the written permission of TCL is strictly prohibited.
Click-through steps：
1) Power off the device, long press “Power” Key
+ “Volume up” key until the LCD lights on;
2) Press “Volume” key to select “Wipe data/factory
reset” and press “Power” key to confirm;
3) Select “Factory data reset” and press “Power”
key to confirm;
4) Select “Reboot system now” and press “Power”
key to confirm.

Service Manual TCL Communication Technology Holdings Ltd.
Rev.: 1.0
TCL 408_T507D1_Service Manual V1.0
Page: 8/30
Confidential and proprietary information contained in this repair guide is subject to change without notice.
Distribution, transfer, copy of any content or data in this document without the written permission of TCL is strictly prohibited.
5 Software Update
It is suggested to upgrade the handset software to latest version for better performance. Before upgrade,
please remember to backup your data and keep your phone fully charged.
5.1 Software update by FOTA
Firmware-Over-The-Air (“FOTA”) is a way in which the firmware of a mobile device is updated wirelessly
by the device’s manufacturer. Firmware runs in the background without any input from the user, to make
sure that the device’s hardware runs properly. Head to your device’s “Settings”-> “System”-> “System
Update”
5.2 Software update by using Mobile Upgrade tool
1) Download the corresponding SW upgrade tool Mobile_Upgrade_S_Gotu2_v1.3.2 from website:
https://www.tcl.com/global/en/service-support-mobile/tcl-408.html
2) Open the download Mobile_Upgrade_S_Gotu2_v1.3.2 Setup.exe file and choose the language,
install the tool according to the prompt.
3) After finish install the tool, click “Finish” and restart your computer.
4) Open the tool, choose the language, select the model “T507”, click “Start”-> “Next” ->click “Yes”-
>Power off your phone and connect it to computer via USB cable and waiting for loading software
package.

Service Manual TCL Communication Technology Holdings Ltd.
Rev.: 1.0
TCL 408_T507D1_Service Manual V1.0
Page: 9/30
Confidential and proprietary information contained in this repair guide is subject to change without notice.
Distribution, transfer, copy of any content or data in this document without the written permission of TCL is strictly prohibited.

Service Manual TCL Communication Technology Holdings Ltd.
Rev.: 1.0
TCL 408_T507D1_Service Manual V1.0
Page: 10/30
Confidential and proprietary information contained in this repair guide is subject to change without notice.
Distribution, transfer, copy of any content or data in this document without the written permission of TCL is strictly prohibited.
5) Click “OK” and disconnect your phone from USB cable when the tool pops up the prompt “Please
disconnect your device from the USB cable to proceed”.
6) Click “Upgrade device” and connect your powered off phone to computer, waiting for upgrade.

Service Manual TCL Communication Technology Holdings Ltd.
Rev.: 1.0
TCL 408_T507D1_Service Manual V1.0
Page: 11/30
Confidential and proprietary information contained in this repair guide is subject to change without notice.
Distribution, transfer, copy of any content or data in this document without the written permission of TCL is strictly prohibited.
7) Upgrade successfully.
6 Function Test with Support Centre
1) Check that the Nano SD card are inserted correctly.
2) Power on the product to launch the auto test.
3) If the product displays “input NCK code”, this means the software is Network locked or SIM locked,
and can only be used with dedicated SIM card hence use the relevant SIM card or enter the phone
NCK code if available.
4) Open the “Support Centre” app->Click “AGREE”-> “Hardware diagnosis”->“START TESTING” -
>Authorize the permissions required for diagnostics->Follow the instructions to test.

Service Manual TCL Communication Technology Holdings Ltd.
Rev.: 1.0
TCL 408_T507D1_Service Manual V1.0
Page: 12/30
Confidential and proprietary information contained in this repair guide is subject to change without notice.
Distribution, transfer, copy of any content or data in this document without the written permission of TCL is strictly prohibited.

Service Manual TCL Communication Technology Holdings Ltd.
Rev.: 1.0
TCL 408_T507D1_Service Manual V1.0
Page: 13/30
Confidential and proprietary information contained in this repair guide is subject to change without notice.
Distribution, transfer, copy of any content or data in this document without the written permission of TCL is strictly prohibited.
7 Troubleshooting
7.1 What should I do if my device reboots by itself?
a) If the issue appears occasionally, it may be caused by anomalies in a file. It is recommended that
you continue to use the device normally.
b) Check if the issue occurs during charging. If yes, we recommend trying the official charger and
data cable.
c) If the issue occurs while using a third-party app, make sure the app is compatible with your
device andAndroid version. Try uninstalling the third-party app.
d) If the issue occurs while using the built-in app, try to reset or update your device.
7.2 What should I do if my device system lags or freezes?
a) Try to restart your device.
b) Charge your device until the battery level is at least 20%.
c) Too many apps running in the background or the system cache not being cleared may cause a
system lag. Touch the Menu key at the bottom corner of screen to view recently used applications.
Touch “Clear all” to close the tasks.
d) Uninstall unused apps from time to time to ensure that your device has sufficient storage space.
e) If the issue occurs in third-party apps, please uninstall the third party apps responsible.
f) If you are playing a game, watching online video or listening to online music, your device may lag
or freeze because of a poor network connection. Enable Airplane mode for a few minutes, then
disable it and check your network connection again. Alternatively, move to a location with a better
network connection
g) Try to reset or update your device.
7.3 What should I do if my device cannot charge or charges slowly?
a) Check if there is any visible damage to the charger USB, the charger itself or the charging port of
your device. If yes, back up your data and take your device and proof of purchase to our repair
center to get more professional technical assistance.
b) Charge the device with a TCL official charger for at least 30 minutes, then try again.

Service Manual TCL Communication Technology Holdings Ltd.
Rev.: 1.0
TCL 408_T507D1_Service Manual V1.0
Page: 14/30
Confidential and proprietary information contained in this repair guide is subject to change without notice.
Distribution, transfer, copy of any content or data in this document without the written permission of TCL is strictly prohibited.
c) Verify whether there are any third-party power management software apps downloaded. If so,
please uninstall these.
d) Please don’t use the device for a long time while it is charging.
e) Try to reset or update your device.
7.4 What should I do if my device’s battery drains under normal use?
a) Check if the device is in a high or low temperature environment. If yes, we advise you to use it
only under normal operating conditions.
b) Deactivate Bluetooth, Wi-Fi, or GPS when not in use.
c) The battery drains quickly when playing games and watching videos. This is normal when
running large games for a long time or watching videos.
d) Too many apps running in the background or the system cache not being cleared may cause
battery draining. Touch the Menu key in the bottom corner of the screen to view recently used
applications. Touch “Clear all” to close the apps.
e) Try to reset or update your device.
7.5 What should I do if my device auto powers off?
a) Power off your device and charge the device with a TCL official charger for at least 30 minutes,
then try to power on again.
b) If the issue occurs while using a third-party app, make sure the app is compatible with your
device andAndroid version. Try uninstalling the third-party app.
c) Try to reset or update your device.
7.6 What can I do if my device heats up?
A warning or sensation of heat in the device is the normal consequence of the CPU handling
excessive data, which makes the battery warm. It is not harmful to the battery or device even if the
device feels hot.
Use the following actions to make your device return to its normal temperature:
a) It is suggested not to expose your phone in sunshine for a long period of time;

Service Manual TCL Communication Technology Holdings Ltd.
Rev.: 1.0
TCL 408_T507D1_Service Manual V1.0
Page: 15/30
Confidential and proprietary information contained in this repair guide is subject to change without notice.
Distribution, transfer, copy of any content or data in this document without the written permission of TCL is strictly prohibited.
b) Close large power consumption applications, such as music, chatting applications, GPS
application, 3D gaming, video streaming etc.
c) Reduce the brightness of the screen to lower the temperature.
d) Avoid using your device while charging.
e) Avoid using a protective case that does not dissipate heat. Remove your protective case if your
device heats up.
7.7 What should I do if my device cannot power on?
a) Charge the device with a TCL official charger for at least 30 minutes, and then try to power on
again.
b) Press and hold the power key for 10 to 15 seconds until the device vibrates, to perform a forced
re-boot.
c) Try to reset or update your device.
If the previously described options do not help, you can contact our hotline or repair center to
get more professional technical assistance. Find the hotline or repair center information from
the TCL website or APP “Support center”.
8 Contact of TCL hotline and service centers
If you are looking for official professional repair, please visit HOTLINE & SERVICE CENTERS (tcl.com)
and search for the contact in your country/region.

Service Manual TCL Communication Technology Holdings Ltd.
Rev.: 1.0
TCL 408_T507D1_Service Manual V1.0
Page: 16/30
Confidential and proprietary information contained in this repair guide is subject to change without notice.
Distribution, transfer, copy of any content or data in this document without the written permission of TCL is strictly prohibited.
9 Disassembly and reassembly
9.1 Disassembly tools
You may use the following tools during the disassembly and reassembly procedure:
Plastic Plectrum
Anti ESD Tweezers
Plastic Spudger
Screws driver
9.2 Disassembly Process
Note：The complete disassembly guide is described as below for your reference, you can
selectively (except disassembly and assembly method which needs to be followed carefully) do
some of those steps according to the spare part which you need to replace.
➢Follow is the complete disassembly process of TCL 408.
Step 1. Power off the device, remove SIM tray and Battery cover.
Step 1.1
Power off the
device ,remov
e the SIM
tray ,cover
electrostatic
protective film
on the screen.

Service Manual TCL Communication Technology Holdings Ltd.
Rev.: 1.0
TCL 408_T507D1_Service Manual V1.0
Page: 17/30
Confidential and proprietary information contained in this repair guide is subject to change without notice.
Distribution, transfer, copy of any content or data in this document without the written permission of TCL is strictly prohibited.
Step 1.2
Remove
battery Cover
using Plastic
Plectrum.
Step 1.3
Separate the
Power_Key
from the
battery cover.
Open the battery cover
from the right side.

Service Manual TCL Communication Technology Holdings Ltd.
Rev.: 1.0
TCL 408_T507D1_Service Manual V1.0
Page: 18/30
Confidential and proprietary information contained in this repair guide is subject to change without notice.
Distribution, transfer, copy of any content or data in this document without the written permission of TCL is strictly prohibited.
Step 2. Remove 19 Screws and Furnished Top Support, Furnished Bottom Support.
Step 2.1
Remove 19
screws by
using Screws
driver.
Screw Torque:
0.8±0.05kgf.cm
Step 2.2
Remove the
Furnished Top
Support.and
Furnished
Bottom
Support using
Plastic
Plectrum.
Step 3. Disconnect the connectors and Remove PCBA.

Service Manual TCL Communication Technology Holdings Ltd.
Rev.: 1.0
TCL 408_T507D1_Service Manual V1.0
Page: 19/30
Confidential and proprietary information contained in this repair guide is subject to change without notice.
Distribution, transfer, copy of any content or data in this document without the written permission of TCL is strictly prohibited.
Step 3.1
Disconnect
the
Battery,LCD
Connectors,R
F cable.
Remove the
back camera.
Step 3.2
Separate the
Main PCBA
and sub
PCBA.

Service Manual TCL Communication Technology Holdings Ltd.
Rev.: 1.0
TCL 408_T507D1_Service Manual V1.0
Page: 20/30
Confidential and proprietary information contained in this repair guide is subject to change without notice.
Distribution, transfer, copy of any content or data in this document without the written permission of TCL is strictly prohibited.
Step 4. Remove the battery.
Step 4.1
Remove the
Battery