iPhone 4 doesnt power / turn on after screen repair
Hi was wondering if anyone could share any information with me about the following.
I have tried to repair a friends iphone 4 as they dropped it and smashed the screen. I have repaired my own phone a few times and others also other repairs like the home on/off button, ear spearker etc. Although this time round i stripped down and put the phone back together as normal with the new screen on it but the phone does not power on. The phone was working fine when the screen was cracked so im guessing it must have something to do with the way i put it back together. I have tried putting a new battery in it and also the hard reset (holing the power and home button together for a while) and nothing has worked. Ive also tried connecting the phone to my laptop but it is not showing up on itunes.
Very stuck on ideas what to do next to try and fix the problem. Dont want to take it to a phone shop as i know they can be funny about working on iphones that have already been opened but i would if the repair is more complex than iam capable of, but knowing the problems before hand will be good to know and could save me from getting ripped off by a phone shop
Any ideas?? please help Thanks