• Samsung SM-J600FN

    Keith • 08/31/2024 at 23:47 • 0 comments

    One morning I rolled over and heard a cracking sound. My phone looked okay at first but I later noticed it had  two definite cracks. Not as deep as the AMOLED, which would have should discoloured as moisture diffused in.

    After previous experience of Samsung, I was going to go very carefully this time. If necessary, I would heat it in the oven to loosen the glue.

    So I bought a replacement for £19. It came with a set of tools.

    The first video I found had no sound. It did show the repairer using a heat gun to loosen the glue, but also using glue from a tube to stick the new screen in. 

    The second video had sound but no commentary. It did show that the display had to be heated to 60 Celsius.

    Some replacement screens come with an adhesive layer, but mine did not. So I bought some E8000 glue. This is supposed to be flexible and doesn't set too fast. What is needed is a rubbery waterproof seal. Cyanoacrylate glues (superglue) are very runny at first (running where not wanted), they set very fast, and lose strength after a year. 

    The display did not work. The phone did not buzz and wake when the power button was pressed. It acted the same when the display was not present.

    I ordered another display. 

    While waiting for it to arrive, I wondered if my phone had simply decided the display was faulty and chose to assume it was dead or missing. Maybe it needed to completely turn off and reset. Google found a page that said press the power and volume down buttons for 5 seconds, then it would vibrate and go to sleep. So I did that, plugged in the first display, and pressed the power button. The display worked (yay!) albeit looking dimmer and greyer than the original. Maybe I could turn the brightness up? I could, by setting "outdoor mode", but this turns off after 15 minutes. So I just turned the brightness up. The second display arrived and behaved in the same way.

    Next step was to permanently fix a display in. I noticed it did not fit well in the cavity. I measured the front glass as 0.6 mm and 1.5 mm of LCD. The cavity is about 0.9 mm for the front glass and 0.7 for the AMOLED display. The front glass overhangs the LCD by about 15 mm at the top and bottom end.

    Graphically, the cross-section looks like the diagram below (scale = 1 square to 0.1 mm):

    Orange is the new screen and green is the phone. I've allowed 0.1 mm for bumps in the LCD.

    There is 15 mm of very thin fragile glass that is unsupported, and largely above the rim of the phone. This is a very weak point. Some vendors know this and warn people not to press the corners! This might be countered by some 0.8 mm shim, but that's not an elegant solution. 

    I suspect all replacement displays will be LCDs and too thick. Even Googling for "AMOLED" returns "AMOLED compatible LCD" screens, not AMOLED displays at all.

    Shopping for genuine AMOLED displays, I found much fewer of them and they are least £43+£6 postage, twice the price of LCDs. I also saw I could get a complete refurbished phone for £45 including postage, so my phone is arguably beyond economic repair. It is 4G, which may eventually be replaced by the 5G network.

    The unsupported gap at each end is 0.8 mm, about the thickness of a credit card. What I might do is cut an old card up to fill the gaps to provide support. Not a great solution but it will make the cheap LCD solution more robust for the remaining lifetime of the phone. Eventually the battery will reach end of life, and be uneconomic to replace.

  • Samsung phone

    Keith • 08/31/2024 at 21:40 • 0 comments

    My workmate had broken her phone digitiser so I said I had done this before and it was not too difficult. I bought a display and had a go.

    Alas, I found the Samsung glue was a lot harder and did not let go easily. I broke the LCD and had to buy a combined LCD+digitiser.

    That was not the end - it did not fit perfectly. I had to file some of the aluminium frame away to accommodate a larger than before ceramic capacitor. The display was a very slightly darker than before, but  was usable.

  • Apple iPhone

    Keith • 08/31/2024 at 21:33 • 0 comments

    Repaired one for my young friend Amber when she was very young (c. 2014). Her mum thought "Well, not much chance of fixing that!" but I could see it was just the display. I bought a replacement and managed to repair it.