I just got through cleaning up after a similar problem. In my case I really believe the glue was too old. I called the eBay source where I got it and was told age shouldn't cause any problem. Have I got news for them!!! When I got the display together I had a few bubbles, so I knew I would have to fix it again. This was my first time using LOCA. I was feeling pretty good that I didn't have any major problems...until I separated it...OMG! Some of the glue had cured but was soft and looked a bit like cottage cheese but clear. Mine also had thick places of cured glue among other areas where it did not cure at all. As you already know, all this makes for one !&&*-of-a big mess to clean! From the LCD to the digitizer, LCD separator machine and the LCD alignment machine! That's not to even mention the work bench... I know there was not an issue with getting enough of the light, it was there for more than an hour. No, after an intense search and reading till my eyes bled, I have come to the conclusion that the...
If I understand correctly, your Grand will not charge and therefore can't turn on. Check your charger port for damage and make sure it's not full of dust. Samsung devices have very touchy charger ports. That little prong inside the port gets abused a lot from the way people plug and unplug. It may just have a crack where it anchors or could even be bent down to where that little tab is not going into the charge cable. If that looks good, you might just need a new battery.
You will have to order a digitizer (very slim film attached to glass) for your exact model. If you have no touch, then the cracks or one, has broken the thin film that makes the touch work. The trick is getting the old one off without damaging any components under it, then getting the new one put in without damage to it and getting and make sure of the particulars so when you turn the thing it will purr like a kitten. There may be an article here for a fully in depth repair from start to finish. If not, one needs to be written (me). So let me know.
I get this problem quite often. I have a SMD/soldering station, but you can use a hair drier. You need: 1. hot air source 2. new charger port 3. tweezers Use tweezers to hold old port while you heat the solder points. Gently lift the old port until it lifts off the PBC board. Discard old port and pick up the new one with the tweezers the whole time keeping the area hot with the air. Set the new port on the board where the old one, was keeping the hot air on it. When it's ready to turn soft and pliable, anchor the port in the space. This process is known as "reflowing". It takes a few times to get better. note: always have hot air moving, never still.