Since I could not find tutorials for replacing a LG US780 digitizer screen (the glass touchscreen part of this particular cellphone) I decided to do one myself. I attempted this job in the blind with no experience and no help... so this method is probably not 100% fool proof. I used what tools I had and even though it wasn't pretty I now have a fully repaired and working phone.
If you are not at least a 6/10 on the MacGyver scale please don't try this. It's cheaper to have a shop do it than to break the phone. However, if you are handy with electronics and feel that you can do this please exercise caution. I am not responsible for you breaking your phone.
Step 1: Gather Your Materials
For this job you will need at a minimum:
(1) jeweler's screwdriver set (mine is a dollar store eyeglass repair set)
(1) short length of scotch 3m double sided electrical appliance tape (bought online with the replacement screen)
(1) replacement digitizer screen for your phone
(1) LG US780 smartphone with a cracked screen
a clean area to work in. I used the kitchen table...
Things that were nice to have:
Latex or similar gloves to prevent fingerprints on your internal parts
A lens cleaning cloth (mine was included in the eyeglass repair kit)
A magnet in an altoids tin (to hold all of your small screws)
An exacto knife. probably not the best tool for the job but it comes in handy for popping the old screen out.
before taking anything apart make sure the digitizer screen you got will fit your phone.The first screen I was sent was for a lg870 the guy at the store was just dyslexic or something. This wasn't a big deal but would have been a bummer if I had torn the phone apart prior to having the right parts.
Step 2: Remove Battery and Small Screws in the Back of the Phone
Lift the rear cover off and remove the battery. Place the phone face down and remove all the small screws that you can see. If they are covered with a sticker leave them alone (You do not need to take the whole phone apart to do the job). Put your screws in a safe place. I use a magnet to hold onto them and to find them if they get lost.
Step 3: Start Taking the Phone Apart
Lift off the top portion with the camera lens attached, place it someplace safe and clean. (pic 1)
locate the important bits and be mindful to not touch or damage your camera parts (pic 2)
There is a thin bumper of plastic (3rd picture) by the headphone jack remove it by lifting gently up and back.
Using some sort of flat device (xacto knife or flat screwdriver) start gently separating the top portion of the digitizer frame from the phone. you only need to loosen the top 1/3 of the frame. Be aware that the digitizer ribbon lives under there, so don't manhandle the parts. Under the digitizer and frame is the LCD display. it is very important to keep this surface clean and free of damage: once the phone is put back together those fingerprints or dust will be permanently part of your display.
Step 4: Remove the Damaged Digitizer Screen
Unclip the ribbon on the back of the phone. The smaller dark orange piece lifts almost straight up. the larger orange square might take some additional finesse: in my phone it was stuck in place with an adhesive as well as two small metal clips, one on each side. (picture 1&2)
It takes two hands and some careful maneuvering to remove the screen so no pictures... sorry. However, instructions follow below:
The layer you started lifting off in the last step is composed of two large components: your digitizer and the plastic frame it sits in. Between these parts is an adhesive tape. Near the bottom of the frame are two little white pads. (see pic 3) The white pads are directly under your 'back' and 'options' buttons. on either side of your 'home' button. try to be aware of them and use a peeling action in the lower area of the screen instead of a sharp scraping instrument (live and learn I nicked one).
to remove the screen I started in the most damaged portion and worked the tip of my xacto knife into the crack between the glass edge and the plastic frame. I gently lifted and slid the blade up along the edge of the screen careful to not hit the LCD display or damage the frame. I blew on the phone periodically to make sure any glass shards were out of the works. The screen eventually lifted off in one piece. I cut the ribbon for the digitizer and set the broken screen aside (pic 3) Locate your little white plastic button pads for the back and home buttons and keep them somewhere for later.
Picture 4 shows the digitizer frame with the adhesive remnants. To remove the sticky stuff gently peel up the edge of the adhesive and peel it off with your fingers. You will want to remove as much as you can prior to installing your new digitizer. This is also a good opportunity to clean any cruft that was stuck between your glass and the frame.
Step 5: Prep the Phone for It's New Digitizer
I used the exacto knife to cut the top of the ribbon tunnel out of the phone so I wouldn't have to remove more parts to install the digitizer (pic 1). you can see I chose to completely remove this little plastic piece but did not damage the surrounding components.
Apply your sticky tape to achieve the fullest coverage your sanity will allow. It doesn't take a whole lot of tape to hold the screen in place after the adhesive has set fully. But the more coverage you get the better the seal against dirt and moisture. (I used the scotch 3M 2mm double sided tape available online)
Do not peel off the tape's backing paper until you have confirmed your digitizer works. This is especially important if you bought it online.
When your tape is all applied and you have cleaned off you LCD display: you are ready to install the digitizer.
Step 6: Install the Glass Digitizer
Making sure your ribbon and digitizer are in the correct orientation (the ribbon comes out of the top left corner of the digitizer if you are looking at the screen of the phone). Set the screen in place and run the ribbon around the back of the screen between the digitizer frame and the modified ribbon tunnel. Plug the digitizer in. Gently press the components back together and install the battery. It is important that no screws or metal bits are in the works of the phone and that you don't touch any exposed circuitry. I installed the back cover for this step. The digitizer controls all touch functions so ensure they all work. i.e. swipe to unlock, open an app, use your back, and options buttons. When you have confirmed it works, take out the battery and carefully unplug/remove the digitizer. if it doesn't work, stop and go back to figure out where you went wrong. Mine worked fine :)
Recheck for dust or fingerprints on your LCD and the back of your Digitizer. If you wore gloves this should be no problem but wipe everything down with the lens cloth anyhow.
Peel off your backing tape and reinstall the digitizer as before. except for-realsies this time. Press gently around the edges of the phone to seat everything and reinstall the bumper and upper back piece of your phone.
TEST THE PHONE AGAIN PRIOR TO INSTALLING ALL SCREWS.
This might just be a superstition of mine but I've always had to reopen a case if I put in all the screws prior to testing the device... this goes for laptops, game consoles, computers, dvd players... everything and anything electronic.
Now, if the phone works proceed to installing all screws again. Be careful to not overtighten, crossthread, or strip the screws, they should go in easy. snug them down but not too crazy. It's a phone not a lug nut.
Once everything is back in it's place, and your phone is working again feel free to celebrate. Dance a bit, text a friend, have an adult beverage, whatever you feel... because you're a winner and you deserve it!