Replaced battery, not turning on anymore

Replacing a battery is a straightforward repair but it can go wrong in a big way if your not careful. Here are some things to look out for:

• Follow the repair guide faithfully if you are inexperienced.
• Always disconnect the battery first and re-connect it last otherwise you can damage the backlight circuit.
• Don’t use metal tools to pop the connectors; this could cause short circuits on the logic board.
• There are lots of tiny components near the connectors; they can be easily dislodged or damaged.
• The FPC connectors can be easily damaged; line them up properly and they should subtly “snap” into place
• Keep track of the screws and where they go. Putting a longer screw in the wrong place you can severely damage the logic board.
• Most iPhones have a pull-tab adhesive to secure the battery. Proper usage allows you to easily remove the battery. If you must pry, then avoid leaning on the logic board or using sharp or edge tools that could puncture the battery.
• Buy from a reputable supplier. iFixit batteries are very good and they stand behind their products. Be wary of low-cost batteries on eBay or Amazon.

Please go through this list and let us know if you did or noticed anything that can help us pinpoint the problem.