Hi all. A month or so back my S6 started to shut down on me when plugged into a power source. It would lock up and usually only boot once the battery was fully drained. It wouldn't boot or power on at all. Once discharged and plugged in it would boot but shut off and restart while in use. Some power management helped, but not for long. My first idea was to replace the battery, as I have before. Last time I ordered an aftermarket battery so this time I decided to go for an "authentic new OEM" battery off ebay. Let's just say I was disappointed when it arrived. Once I exchanged it, the issue was not resolved. I suppose my question is if this would be a mainboard problem? This isn't my main phone anymore, but I would like to fix it and give it to someone. Thanks in advance!