Original post by: Jesse Hooton ,
Well you did rule out a bad battery by the sounds of it. If you have a known good screen give that a shot. If you have a DC power supply, try hooking it up to that. If it draws amps before you even press the power button, then there’s a short before it’s prompted to boot, and can prevent them from turning on. You could send it to iPad Rehab or STS Telecom for further diagnosing and or repairs if necessary.