Hello
Does anyone know about NB4 strange beeping sound on startup? Device emits weird repetitive sound & doesn't boot up at all. Top led doesn't have light.
If it's used without bottom battery base - no more sound and doesn't work either.

PowerBank seems to be okay, it charges my phone. As a guess, maybe I have to replace 18650 battery?
Unfortunately, I cannot share YouTube video link so check attachment (zip file with short video).

Thanks in advance.