Chosen Solution
So I got these synchros s400 bt and for some reason when I go to charge the light around the port goes red and stays red. I dont know what’s wrong.
Hi @spongebobsquare , I think that the battery may be failing and needs to be replaced. Even rechargeable batteries have a lifespan I cannot find a teardown or battery replacement guide or video for the headphones but here’s a video that may be of some help. At approximately 1:22 minutes into the video the battery can be seen. Replacement batteries are available online. Just search for JBL Synchros S400BT battery to get results for suppliers that suit you.
