Thursday, June 7, 2012
Found/Fixed an LG C729 android phone with broken screen
I found this on the street in front of my house. It is a nice android phone that had been
run over by a car. I couldn't believe my luck. The screen is broken badly. This is the most fantastic thing I ever found. The screen is splintered and I got some shards in my finger trying to see if the touch pad works. It doesn't at all. That is the biggest problem. The back won't stay on and the battery is pretty roughed up too.
I set out to find out what data I could pull off the phone and what functionality I could use. I'm a hardware experimenter, and I'd like to use it for telemetry, robot control, etc. For that I don't need a screen, the sensors, camera, GPS and USB interface alone make it very powerful. It has an SD card it in, a SIM card too. Who does it belong to? If it were an iPhone, I'd buy a screen replacement kit, but this is a fairly obscure LG C729 .
This looks like a very dicey site. But it led me to a part number, then
Looked up model, it is an LG Doubleplay from T Mobile. Runs Android 2.3.4 It is a practically new phone. I can't imagine why whoever dropped it and ran it over didn't come back for it.
I found the SD card was unformatted and had no data on it. I guess the phone was pretty new.
The SIM card from Tmobile... is it still active? I can see that the phone is saying no signal, emergency calls only, so it's cancelled as I'd expect it to be. The phone sat around for a couple weeks before I got a chance to play with it.
A little fiddling and I was able to put the battery in, and connect the USB and power it up. The backlight comes on and with the battery in in actually boots. It makes sounds. This phone seems good except for the screen. For some reason it didn't work the first time I tried, but later it did boot. Plug it into the USB and screen lights up but is pretty bad shape. I think the screen lock is on, and since the touch pad is smashed, I can't unlock it with a swipe.
Another lucky part is this wacky phone has a second touch screen inside the keyboard. That touch screen actually works still and is not broken. However it doesn't fully run the phone. I can open text messaging but not the contact list to see who's phone it is.
When it first booted, I was able to operate the phone. After a while it went to screen lock due to inactivity and I can't see a way to get it out of that mode. It is hard to turn the phone off again, because long button hold brings up a menu that I can't operate to do a shutdown. I did find the physical keyboard space and return allow me to navigate the power down menu. W00t! Any other phone and I'd be nowhere, but this oddball has a physical keyboard.
Android Java SDK talks to the phone, it seems to load apps I program in, when the power is off! When turned on I can't go through the menus to set the phone menu option to allow Settings->Applications->developement which allows USB loading of programs. When powered on I can't talk to it with eclipse. Very strange. This is a major obstacle to using the phone as a hobby robot.
I thought I would need to write an app to unlock the screen when the touch swipe won't work
Pryed off the back and pulled out the keypads from each side. This allows you to wedge a screw driver in sideways and access the other two screws on the back of the sliding screen. You have to pry up the circuit board a bit and slide the screen around until you can just wedge in the screwdriver and remove the two screws opposite the ones that are easily available under the rubber bumps.
Couldn't photo that step because it took both hands :).
Prying open the screen section. There is a flex circuit board wiring that ties it all together. it is taped to the back of the LCD. Peeling it off the old LDC was scary stuff. The connectors are the silver rectangles. They pop off with a tiny bit of prying. There is one for the LCD and one for the digitizer. Just look at the new parts and you'll see where they connect.
Old screen was glued in and was a mess of broken glass. Easy to get cut.
Peeled it out, but it's not all out yet. Need to save the plastic bezel. Too bad, it's pretty messy.
Plugged it back together, put back the back part of the phone so I could power it up. Holy crap! It's alive!!!
The touch screen works, the LCD lights, the home button works. The physical keys still work. This thing is fully functional. Removing the sim was a mistake, when it was put back in, it wiped the phone. No worries, I had already read the email when the screen was broken and it was totally lame stuff.
Still need to figure out how to put the front panel back together and scrape out all the old broken glass.
I'm kind of surprised the thing works, it took a ton of prying and poking to get to this point.
If you want to do this on your own phone, that you want to be good as new, geez, good luck. I only had the nerve to do this because the phone was junk and I had wasted $$ on replacement parts and didn't want to let them go to waste. I may never get it all back together good as new.
Posted by siliconfish at 10:57 PM