Sony LinkBuds Clip (WF-LC900) FCC Teardown
Opening up the other side reveals the following.
- Wireless antenna contact
- LDS antenna contact pad
- Unknown IC
- Possible glue/seal for IPX rating
- Second MEMS microphone
- Bone conduction sensor
- Charging pin connections
The unknown IC (#3) is also present in other recent Sony earbud models, so whatever it is, it looks to be important.
A close up of the wireless LDS antenna backside and the connection pad.
The LDS antenna is printed on a separate piece of plastic, which is inserted into the main body. From my quick reading online, it seems that a printed solid antenna is superior than a flexible PCB antenna, as they perform better and are less susceptible to interference.
A close up of the back of the main earbud PCB (right side). The left side of the PCB has the connection for the main ribbon cable assembly. The connector can be seen in the photo below.
The topside of the earbud PCB. The Bluetooth SoC is covered by a metal shield, with the shield and battery both covered by a plastic moulded piece. This is the only photo where the plastic piece if shown.
The metal shield covering the end of the PCB differs in shape between the left and right side. I suspect the reason is because of the different component layouts, but why are the PCBs laid out differently? Usually Sony earbuds have the same PCB designs except mirrored. No doubt the reason is probably obvious, so if anyone knows, please drop it in the comments.
A close up of the main Bluetooth SoC, the Airoha AB1585M
We can see that Sony decided against using the V2 (MT2833) in the LinkBuds Clip, and went with the Airoha AB1585M. This cannot be the reason for the absence of LC3 support, as the AB1585 also has LE Audio support. Hopefully Sony will add LC3 support in a future firmware update.
Although not confirmed by Sony, and only through various online information, the V2 may just a variant of Airoha’s AB158X platform, the AB1588. There could be additional customization from Sony through Mediatek of the AB158x, but there is no way to know what that could be. Why Sony did not just use a V2 is a mystery.
LinkBuds Clip internal battery – Zenipower Z35FH
Finally the earbud battery. The FCC photos reveal we are looking at a Zenipower Z35FH, 3.85V 54mAh coin cell. The Taiwanese certification has 2 batteries for the earbuds, both Z35FH, but one is 56mAh and the other 54mAh. I have no idea why there are 2 different versions of the same battery. The LinkBuds Fit and Open use the same battery.
This is the only photo of the battery, meaning we have no information how the battery is connected to the main PCB. I suspect the battery is soldered to the board. Therefore a battery replacement would be more difficult and not easily performed at home.
This concludes the FCC teardown. If anyone sees anything I missed, drop it in the comments,
