Phone not booting after drop. Black screen

What do you mean “has no value”? Do you mean it’s reading OL on your meter in resistance mode, reading 0 (ohms or volts) or do you mean something else?

At any rate, if you want to rule things out, just connect the logic board to a known good Lightning flex and battery (or DCPS) and see if the computer recognizes it. After a hard drop, almost anything can happen so there’s no silver bullet here. Probe the main power rails to start, then move onto secondary rails if required. You can also probe the BB subsystem. With more info, we may be able to point you in the right direction.