My jbl xtreme 2 will not turn on and the connect button flickers

I have a jbl xtreme 2 that turns on only on the charger. When I take it off I can use it perfectly for more than 20 hours. But when I try to turn it on off the charger the connect light flickers every time I press the power button or nothing happens. After around 10 try’s it to turn on off the charger though. I have tried all troubleshooting and even jbl support doesn’t know what’s wrong. They say probably a board issue. And help us appreciated.