Black Screen Post Repair

I replaced a digitizer on an iPad mini 2, the tablet was partially functional prior to the repair (the screen was cracked and the top half of the digitizer was dead. I was unable to turn it off prior to the repair). After tearing it down and replacing the digitizer, the tablet doesn’t turn on. I’ve tried a new LCD and a second digitizer. When I attached it to my Macbook, the computer recognized it and said it was in restore mode and would need to be resotred to work, however I still do not have any image on the screen. I’ve checked with a flashlight to make sure it wasnt the backlight to the best of my ability. I’ve attempted a soft reset. The only think I have not attempted was a battery replacement as I do not currently have access to a battery replacement for this particular device. Any advice would be helpful!