The Redmi Note 9 5G, equipped with a large battery for extended usage and stereo dual speakers, is priced at around 1000 yuan. In the 5G smartphone market, this price point is considered the lowest. Disassembling mid-range devices priced around 1000 yuan is generally straightforward, and the Note 9 is no exception. Many may wonder if any corners were cut and how costs were controlled.
(The device purchased is the 6GB+128GB version, and the disassembly data below is based on this device.)
The main reason for acquiring the Redmi Note 9 5G is its use of the Dimensity 800U processor. eWisetech analyzed the supporting chips through disassembly and filled the data into the eWisetech database. Therefore, we have organized and analyzed the ICs of the entire device, during which we discovered some interesting details.
(▼ IC markings on the front and back of the Redmi Note 9 5G motherboard)
To briefly introduce, the Dimensity 800U is a 5G mobile processor released by MediaTek in August 2020, based on a 7nm process. It features a 2+6 octa-core CPU architecture, including two ARM Cortex-A76 big cores with a frequency of 2.4GHz and six Cortex-A55 small cores, while the GPU is the latest generation ARM Mali-G57.
Products are naturally compared, and it is not difficult to find that the Dimensity 800U seems to be a lower-spec version of the Dimensity 800 and an upgraded version of the Dimensity 720. During disassembly, it was also found that the Dimensity 800U processor chip shares the same packaging model as the Dimensity 720 (the only difference being the batch number and serial number), with the packaging model being MediaTek MT6853V, and the die is the same.
After comparing the BOM of the realme V5 equipped with the Dimensity 720 and the Redmi Note 9 5G equipped with the Dimensity 800U, it was found that the supporting chips of both platforms are basically the same, with only slight differences in the RF transceiver models.
The complete IC BOM of the device can be queried on eWisetech to understand the material costs of the Redmi Note 9 5G. Now, let’s return to the disassembly to see if any corners were cut.
Disassembly Process
Before disassembly, remove the SIM card tray. The front of the tray has Chinese markings to prevent incorrect insertion and is equipped with a red rubber ring. The Redmi Note 9 5G uses a three-card parallel tray, supporting two Nano-SIM cards and one MicroSD card with a maximum capacity of 1TB.
The back cover is secured with clips. After opening the back cover, the side-mounted fingerprint recognition soft board is connected to the mainboard and is fixed with a metal plate and screws on the BTB connector, preventing direct removal of the back cover. Additionally, there is a small amount of foam adhesive between the back cover and the camera protection cover to seal the gap and provide some dust resistance.
There is foam on the back cover, and FPC antenna soft boards are attached to the upper and lower inner sides. The buttons and fingerprint sensor are glued to the left and right sides.
The motherboard protection cover and speaker are secured with a total of 17 screws, two of which have tamper-proof stickers. The rear camera protection cover is integrated with the motherboard cover, and the surface of the motherboard cover is attached with a layer of graphite thermal pad, with shock-absorbing foam located at the main camera’s fixed position.
The Redmi Note 9 5G features a closed integrated sound cavity speaker, with the speaker module provided by AAC Technologies. The surface is covered with a layer of graphite thermal pad, and there is a PCB antenna board connected to a coaxial cable at one corner on the back.
The internal assembly is in three segments, with copper foil and graphite thermal pads attached to the surface of the motherboard. All four cameras are independent modules, with three rear cameras equipped with plastic positioning brackets, and two of the cameras are secured with steel plates at the BTB interface.
There is one fixed screw on the motherboard, and the connection between the main and sub-boards, aside from the cable above the battery, includes three coaxial cables secured in the recess on the right side of the internal support. Although the surface of the motherboard shield has copper foil and graphite thermal pads, no thermal grease or similar materials were found between the motherboard and the internal support. The USB port and headphone jack are equipped with silicone dust caps.
The battery of the Redmi Note 9 5G is secured with two pull tabs, with a rated capacity of 4900mAh, sourced from Zhuhai Coslight, model BM54. Next, we remove the earpiece, independent light sensor module, and linear motor. The independent light sensor module is equipped with a silicone dust cap, and copper foil is also attached to the soft board.
The top earpiece component is slightly larger than typical earpiece components, featuring a dust-proof mesh and a small amount of foam adhesive. It integrates sound output functionality, but due to size constraints, the sound output from the top and bottom speakers is uneven during actual use.
The Redmi Note 9 5G features a 6.53-inch single punch-hole IPS full-screen display, with a layer of graphite thermal pad between the screen and the internal support.
In summary: As a 5G smartphone priced around 1000 yuan, the Redmi Note 9 5G offers relatively good workmanship and user experience. Its internal design is in three segments, making disassembly straightforward and facilitating repairs. However, the Note 9 5G’s cooling method is relatively simplistic, relying only on copper foil or graphite sheets for heat dissipation on the front and back of the motherboard and the camera base, lacking thermal grease.
On the positive side, the battery is secured with pull tabs and also features a plastic film. As we know, pull tabs often break during disassembly, but the film can be used to assist in the process.
This concludes our disassembly share of the Redmi Note 9 5G. I believe that while the Note 9 5G achieves 5G at a price point of around 1000 yuan, it cannot be said to have “cut corners,” but it is destined to sacrifice some aspects. Do you have a different opinion on the Redmi Note 9 5G? Feel free to leave a comment for discussion!
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