Chosen Solution
I forgot to unhook the battery. Self teaching repairs. IPhone 8 front can ribbon flamed up a bit and the screen had worked prior. Did I damage the logic board, battery or screen… or all 3? Won’t turn on at all now. Suggestions for a device to test screens? Device to test separated logic boards? Thanks!
Sparks and smoke point to a short to ground and burnt components. Try unplugging both cameras connectors, disconnect and reconnect battery and see it the phone starts without those parts in place. In case it doesn’t the logic board sustained damage and needs to be fixed at microsoldering level. If it boots, plug back the rear camera, replace the front camera assembly and reassess damage. There’s not much else one can do beside replacing parts on an iPhone without professional tools and skills.
