No power/POST after replacing screen assembly

My Dell Inspiron 13” 7373 was working normally, aside from a broken screen. After replacing the screen myself, the computer will not power on. The power status LED on the front is off, the power button LED is off, the screen is off, and the keyboard backlight is off.

I have already tried disconnecting the battery and power adapter and holding the power button for 30 seconds (to drain residual “flea” power). I have also tried connecting the power adapter and holding the power button for 30 seconds (to reset the RTC). I also tried turning the computer on with only the battery connected and with only the power adapter connected. None of these steps made any difference.

The replacement screen is from parts-people.com, and I verified that it is compatible with my laptop. I performed the replacement while wearing an ESD wrist strap and on a dissipative mat. I first disconnected the battery, then disconnected and removed the screen assembly. I installed the new screen assembly and connected it. The MB1 connector is fully inserted and the retaining bar is latched. The MB2 cable is fully inserted into the ZIF connector which is fully latched. I then reconnected the battery and attempted to start the computer. The CPU heatsink was slightly warm to the touch, but nowhere near normal operating temperature. The power adapter and the battery are both providing the expected voltages.

I’m out of ideas, so any assistance would be appreciated.