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I have a iPhone 6. The screen was cracked so I replaced it with a another after market screen. I made a mistake that I forgot to unplug the battery. I think there is a electric overflow at the time when I connect the screen (I believe the display connector for lcd?). I heard the spark and smell the burn.The phone either does not display anything orget a screen that looks black but actually can see dim backlightsNo image any way but detected by itunes The screens I try work fine on another device so it is not the screen. I think it is the display connector for lcd that was burn/suffer from electric overflow. I am not exactly sure, the appearance does not look any different to me examining at the ports side by side with a good working phone. Is this the problem of the display connector as I inferred? Is it possible for me to fix it with soldering + a new display connector? I am not sure how to fix this. any advice is appreciated thank you.

When you connect a screen on the iPhone without disconnecting the battery and you hear a spark it usually means you have blown the backlight. Make sure what you see on the screen is an image without backlight. Shine a torch at the screen ideally when booting to see if you can make out the apple logo. If you have backlight and no image the repair will be a lot more difficult for someone without the right equipment and experience. Let us know what you are missing.