Today we dismantled the wireless headset, Huawei FreeBuds 4i. Support active noise reduction, use BES2500Z Bluetooth audio SoC, support Bluetooth 5.2 technology. 55mAh headset battery + 215mAh charging box battery, 10 hours of continuous standby, priced at 499. It sounds like, hey, not bad!
Whether the product is good or not, I will show you the disassembly to know!
Small-size products such as earphones are usually fixed with glue around them, and there are many glues inside. The disassembly is simple and direct violent disassembly, and the components are also very simple, usually mainly speakers, FPC soft boards, batteries and motherboards. .
The same is true for FreeBuds 4i. When opening the shell, you need to pay attention to that the charging contacts are directly welded and fixed with the motherboard, and the motherboard can be removed directly after prying.
The connection between the internal device and the main board is connected by two BTB interfaces on the back, and the corresponding FPC is fixed on the shell through a black plastic sheet. Note the details of the headset, such as the position of the microphone on the shell and the position of the noise reduction microphone on the left, with foam and black tape.
When separating the FPC cable and the fixed plastic sheet, you need to pay attention to the touch FPC under the plastic sheet. Since the device is small and fixed with glue, be careful when disassembling to avoid damaging the FPC.
The battery, speaker and FPC soft board part need to be removed by prying open the front shell of the earphone. And the whole circumference is filled with glue, which makes it quite troublesome to separate the devices. The front shell is provided with a dust-proof net on the inner side of the pressure relief hole and the tuning hole. Above the battery is the ZIF interface to connect the speaker.
Slowly remove the glue to separate the device. There are magnets, speakers, battery plastic shells, batteries and two FPC soft boards. The metal contact in the middle of the FPC is the charging contact, and the two ends are the touch detection and wear detection parts.
Disassemble the charging case
The disassembly of the charging box is relatively simple, and it is mainly fixed by buckles and glue. Pry open the inner shell to see the complete internal structure.
Corresponding battery and USB interface parts inside the shell are pasted with black foam for protection. The side buttons can be taken out directly after removing the internal components, and there is a purple silicone ring on the buttons.
The USB charging port at the bottom of the soft key board is equipped with a silicone pad and a silicone protective cover. The status indicator composed of two LEDs is also provided with rubber parts around it to avoid light leakage. Although the disassembly of the charging box is relatively simple, the internal structure is relatively more complicated than that of the headset. It is roughly divided into three parts, the first is the plastic cover fixed with screws on the top, the support inside the charging box and the main board part.
There are multiple FPC soft boards in the whole interior. The charging thimble FPC at the top of the inner support is fixed by a hot-melt column, and the charging shrapnel at the bottom is directly welded to the FPC. The LED soft board and battery FPC on the main board are also directly soldered on the main board, and the soldering area is also coated with yellow fixing glue.
Directly pry off the charging thimble FPC on the inner support, and the side buttons are also on the same FPC. There is a magnet on the inner support, and two silicone rings can be seen at the position of the charging thimble.
This part of the motherboard is mainly the battery, the bottom plastic cover, the motherboard, the LED soft board, and the USB plastic cover. There is a white waterproof label inside the silicone sleeve outside the USB.
Disassembling the upper earphones has increased the difficulty of disassembly because of the internal glue filling. Huawei FreeBuds 4i did not specify the waterproof and dustproof level, but through disassembly, you can see that a lot of silicone rings are used inside the charging box, and the details are still very careful.
After sorting out all the ICs, it is found that the earphones plus the charging box chips are all domestic chips. The Bluetooth antenna is a PCB onboard antenna, which is drawn directly on the motherboard. The touch and wear check uses Goodix’s capacitive in-ear detection and touch solution. One of the earphone charging pads is directly soldered on the motherboard, and the other is on the FPC soft board.
1: BES- BES2500Z-Bluetooth Audio SoC
3: ETEK–Lithium battery charging chip
5: GOODiX- -Capacitive in-ear detection and touch 2 in 1 chip
6: Hall sensor
Charging box motherboard:
1: Nationstech–32-bit general-purpose microcontroller with M4 core
2: ETEK- ET9562- lithium battery charging chip
The detailed analysis of Huawei FreeBuds 4i can be found in eWisetech, as well as TWS headsets of major brands and various digital products.
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