原帖由： john ,
In most cases its a loose connection or you need to reset the device. On the other hand I've actually seen screens go white that are defective. To double check, I hang on to a couple of old cracked screens just to connect up to rule out a bad replacement part. Be careful though, pulling up that logic board over and over to re-connect the (thin cable) to the bottom of the board can be trouble - logic boards have a tendency to snag the power/volume flex cable and tear it, which means soldering and a lot of hassle. I smooth down the power cable with a pry tool and stick on a piece of Kapton tape (after a few "costly" mishaps) before pulling up the logic board. Last, don't use your finger to snap down the cable onto the board -- use a pry tool - gently, because too much force can break off the connector on the logic board and your into big mess.