How to check if the battery is charged?

@yz06 you cannot test the board and function of the board, without power. I suggest that you replace the connector and then re-evaluate your Vita to ensure the functionality. You can always get a couple of connectors from places like this and many others. Now, unsolder the old port and replace it with a new one. I would also replace the battery since you don't know any history on that. At least with a new one you have a known-well starting point for further troubleshooting. Now you can check the board

The repair is performed similar to this If that task appears to daunting, you can always send the board off to have the port replaced by someone that has experience with microsoldering. There are a few people on here that are known to the community and can be recommended. It'll depend on where you reside (Country) so we can check on that for you, if needed.