JBL Charge 2+ Speaker Not Powering On or Charging, No LED Response

Hi everyone,
I have a JBL Charge 2 with an issue. The speaker does not turn on normally. When I press and hold the power button, the LED on the power button lights up white, but as soon as I release my finger, it turns off.
I disassembled the speaker to investigate and started focusing on this problem.
i try turn on only motherboard without motherboard of usb and charging port and same issue









JBL Charge 2+ Speaker Not Turning On or Charging, Unresponsive LEDs
AI: did you try using different charging cable or adapter to see if the speaker reacts any different?
yes i try another cable and another adopter
AI: have you checked the battery voltage with a multimeter or tried another battery to see if that changes anything?
yes it show 3.7 v

I had a similar problem once. I replaced the battery. Mine was already swelling and could not be charged. But without measurements it's hard to tell if the battery has the right voltage.