Bamboo GT won't power on Light blink One time then nothing

Hi everyone!
So I have been a Bamboo GT since 2017.
My bamboo GT won't power on.
When I push the power button, the blue light blink ONE TIME, and then nothing. I would to know if you believe it's battery or motor controller...
The board has taken possibly some water/humidity. but everything was working fine. After one night the board refused to power back on. I opened everything, no sign of water inside, no dust ... just this ONE TIME blinking and nothing ...

I 'd appreciated views, help and advice ... thanks a lot