Answer to: iPhone 5s stuck on Apple logo after screen replacement?I've seen this happen when proximity sensors wasn't plugged in all the way or got shorted out. He may of replaced sensor and sensor shorted out. Try a reboot and f that doesn't work then have him look into connections
Answer to: iPhone 5s will not turn on or charge?Charging dock....
Answer to: Apple Icon blinks after battery replacementFaulty battery, try another. There isn't enough juice to power on completely.