Hi Dustin! This is the website that sells Smartphone's LCD Screens in bulk, and they almost always have a huge stock of broken (but tested and working LCD Screens). I Hope it will be helpful for you. en.Smartphoneslcd.com.
When it comes to Note 2, and other Galaxy S and Note series You need to replace the entire panel not just screen, and I really don't know how come you managed to replace only digitizer not the panel. You need to buy an original panel not just the digitizer, then it will surely work. However for your current Samsung Broken LCD Screen, all you have to do is to sell it at http://www.brokenlcds.com, as this is known to be the website that buys and recycles broken LCD screens / panels of Smart phones. At least it would help you to cover the cost of that broken LCD Screen.
This must be the problem with your display connector, as if it loosens then you might not get any display on your screen. The very first thing that you need to do is to get any other good and working LCD in order to verify where is the problem whether it is your LCD, Connector, display strip, connector etc. However there are a lot of things that you need to check. Here is a blog that has defined step by step solution in order to overcome this problem, i hope it will help you in resolving this problem. http://blog.brokenlcds.com/iphone-4-display-problem/
Well the best thing that you can do is to get it from an authorized Apple spare parts dealer and get it fixed with the help of a professional iPhone repairer. Don't try to replace the screen on your own, as one needs to have steady hands and a good experience in order to get this thing done, else you might damage it even further.
The problem could be anything, it could either be water damage or your charging pin could be damaged (Due to any physical or any other type of collision). or it could either be: Charging Connector is water damaged Dry solder of connector pin Pins doesn’t make contact with board Faulty components. Anyways here is a blog that has explained this thing in a step by step manner, for you to know how can you overcome this issue, i hope it works for you. http://blog.brokenlcds.com/iphone-4-charging-problem-solution/
Tompkins, the problem could be anything. It might be a software glitch or a hardware error. If this thing doesn't gets resolved with re-installation of software than its surely a hardware issue. I was facing similar issue, (mine had a Camera Strip problem). Here is the link of blog post that might assist you with your iPhone's Rear Camera Prob http://blog.brokenlcds.com/identifying-and-resolving-iphone-4-rear-camera-problem/ or at least it is going to help you in identifying the issue. :)