Replacement screen doesn't power up?

After a drop, screen was badly cracked but still functional. I ordered the ifixit replacement screen and also a replacement battery.

Replacement was uneventful. I reassembled without adhesive to test fit and confirm everything was working. Screen stays dark. If I press the power button I get the haptic vibration indicating that “power off” options are on screen. Holding the power button for 20 seconds gets another vibration consistent with a power cycle. I’ve tried putting the screen under a very bright light to identify if its a backlight problem, but I can’t see anything at all — seems to be completely dead.

The repair was straightforward — I don’t know of any point when I might have damaged the replacement screen. Other possibilities?

iFixit is sending me a replacement screen. Hopefully it will work properly.