Motherboard randomly died on me?

So I just bought a second playstation vita off of ebay with some minor issues. When I got the device I powered it on and most things worked, the left d-pad button wasn’t working and neither was one of the joysticks. I open it up, there are some loose connections that I plug back in, and I reassemble the device. Any sign of power is GONE. No orange charging light, nothing on screen, nothing. So I put the board in my good vita with known working parts that I use quite frequently, and it doesn’t power on either. Is my board dead? It was working before I connected everything so I’m quite puzzled! Thanks in advance for any help!