iPad Air no power

I bought a used non-working iPad Air A1474 off craigslist. The guy said he thought it had a battery problem so replaced the battery cracking the screen in the process so he installed a new screen kit. After this the iPad wouldn’t boot so I bought it as is with the idea of learning iPad repair.

Plugging it in with a digital volt/amp meter it shows 0.00 charging. It doesn’t boot or show any sign of life. So I removed the screen but don’t see anything that isn’t connected properly.

Any ideas on where to begin in locating the problem?

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