This Instructable is made specifically for the the phone I own and repaired, Samsung Galaxy S2 Epic Touch. It doesn't mean that the same technique won't work on another phone, I just won't know another phone's idiosyncrasies like I know the one I opened. Furthermore, the reason why I discovered the idea is from a Galaxy S3 video posted by jpatt2020 https://www.youtube.com/watch?v=9ZKlsQF4LE8 since video's for the S2 Epic Touch were lacking.
The next thing I would like to say about my repair is it still seems intermittent (which is a far cry from it never getting a fix..ever). I did not have any dielectric grease, like he did in the video, though I have used dielectric grease in many other electrical connection applications, it also prevents corrosion.
That being said, I am not opposed to going back in my phone to apply this grease, I didn't want to delay getting this posted for S2 owners, and I can update the instructable after I use the grease if it makes it noticeably more stable.
I believe I know why the S2 has such a terrible history with a gps fix and my technique for the S2 should still be followed. More on this later in the Instructable.
Step 1: Begin by Powering Down
While it is powering down, remove the back cover to reveal the battery. Once it's finished powering down, remove the battery.
Step 2: Remove the 6 Screws and the Micro Sd Card
Forgetting the SD card while making sure you don't forget any of the screws can make you wonder why the back cover can't be removed..because the back cover won't clear the micro sd card while it's inserted.
It is at this point I would also like to point out the gps antennas that I don't believe are making a contact at all with the motherboard. They are underneath all of the square and rectangle shapes, between the white circles in the picture, with a black coating on them. It is from the video that I learned the contacts on the antenna may not be making a contact with the motherboard, even though they are touching. I'll explain this in a few more steps from now. We'll continue to open the phone.
Step 3: Remove the Back of the Phone at the Charge Port First
The ear phone jack fits inside a hole at the top of the phone so you might even break something trying to pull the top away, without loosening it at the bottom, then being able to lift it over the ear phone jack.
No special tools were required for this. I used my finger nails to pull at the edge and lift it over the tabs.
Step 4: The First Look of the Motherboard, Once the Back Is Removed
The circled points on the motherboard come into contact with the metal on the back of the phone to enhance gps reception.
Step 5: My Theory As to Why You Don't Get a Gps Lock Is Revealed
Even though the contacts at the motherboard touch the surface of the antenna, I do not believe there is a metal to metal connection. You can use a small standard screwdriver pictured here, or a metal pick to gently scrape away the material that coats the point of contact. Do this for all of the locations that the motherboard will come into contact with the back of the phone.
Step 6: Once This Surface Is Cleaned, You Should Get a Gps Fix
Since I haven't applied the dielectric or contact grease, which should improve the connection hands down, I sometimes don't get a fix, or it takes a long time, 1 minute to 20 minutes. So it will save you time if you open your phone with the grease on hand, and do the whole thing in one shot.
For me, and many many other S2 owners, getting a fix at all will be proof that what you did improves the gps performance.
I did slightly manipulate the contacts on the motherboard ages ago, thinking that's all I needed to do for the gps to work and it still wouldn't. I didn't mention manipulating them as part of my instructable because I don't believe they need to be adjusted, compared to making a metal to metal contact, antenna to motherboard.
Lastly, I use the app GPS Test. If I'm not getting a gps fix, I will open that app to see if it shows any or how many satellites. Remember, weather can affect reception too. mod
Step 7: The Final Update. Kind of a Relief for Those of You Who Have Tried So Hard With Receiving a Signal
Let me explain what happened here. It took a few days for those of you who were waiting for an update to apply contact grease. I recommend it. If it's not worth the 10 percent increase in signal strength I experienced, there will be some protection from corrosion, when you lightly scratched at the coating to make a better connection. I used a 2.50 tube of Ox-Gard, sparingly.
The series of three pictures above represent the fluctuation in signal about 3 to 4 seconds apart. I was driving down the road and my wife was taking pictures of it in the dash. The most important observation I made was when she initiated the phone's gps and turned the GPS Test app on, nothing happened. We watched for about 10 seconds, nothing. I asked her to turn the phones gps off, then on again, as if the phone indicates it is searching for gps when, in fact, it is not.
When the phones gps was turned on the second time, it locked in 1 or 2 seconds, and showed a signal strength as portrayed in the pictures.