[XPERIA X1 General] uiflorin:
The crack near the volume buttons is a sure thing...

Same crack as the one on top of the list near the volume buttons. I had the phone for 1 week, handled like a piece of expensive Murano glass, stayed on a leather pouch all the time. My colleagues at work were super excited, after I shown them the wireless speed, the multimedia capability, gmail on the go pop-smtp, gps mapping and the rest. One of them is fighting with his wife to allocate the 400euros for it. And then I got the crack!!!!

Anyways, I'm really disappointed with the mechanical design, being an engineer with both mechanical and electrical education and experience with prototype manufacture design. I opened the back, unscrewed it and got the back case out. Well, it's ridiculous design, in fact this crack has to appear anyway...it's the perfect example of inexperience combined with tight design requirements. Let me explain it. The back case it's just a frame around the battery, that covers the camera on top and the speaker and microphone on the bottom. This frame is thicker on the right side where the stylus is inserted, and has only 1mm max thickness on the left. Exactly where the crack appears there is an extra recess for the battery, that minimizes the thickness even more, practically has like 0.7-0.8mm. The designer could have increased the phone width by one millimeter and this could have been avoided. OK, so why is cracking? Because there is a stress on the corner of the frame, exactly where the thickness is at minimum. The stress is caused by the battery, or to be precise by the force of the battery contacts. These contacts push the battery to hold it inside the frame. I pushed only the battery against the contacts with my fingers and discovered that these contacts push the battery also at 90deg, towards the battery cover. This force is lifting the frame through the battery (the battery is held by the two recesses on the contacts side). The back frame is attached to the rest of the body with two screws on top, near the top edge, and then is clipped all around the frame. Because of the volume buttons there are no clips on that spot, but immediately next, so the thin side of the frame is clipped and held firmly, the force of the battery contacts ripping the frame in the weakest spot. Look at the picture, it says more that a thousand words. A screw in that point would have fixed the problem. So, can we do something? Yes, there is something we can do before it cracks.

1) The force developed by a spring is proportional to the travel distance. Use tweezers to push the contacts, one by one, to bend them forcefully inside by 1mm, to lower their force exercised on the battery by lowering their travel when the battery is inserted. I pushed them like in the picture (it's paint job on the picture), such that one is pushed more then the other for each pair of contacts. Don't worry about the contact resistance, it's more than enough force and the contacts are gold plated. The one in the center doesn't need force like the other contacts that pass the whole current, it's the charging monitor and the current is micro-amps. Try to insert the battery several times to feel the lower force exercised by the contacts, but still have the contacts travel a little when the battery is inserted. This can ease the stress on the weak spot of the frame.

2) We can fix the frame before or (sadly) after the cracking. Take the frame out (look on youtube that video explaining how to take the back cover out). Then apply on that spot (only on the inside) where it's supposed to crack (or where it's cracked already) some A+B resin to strengthen (or glue) the frame (make sure the resin sticks to the plastic, maybe you can scratch a little a pattern to increase the sticking of the resin). Use the battery placed inside the frame against the recesses to see how much resin you can add there, such that you don't put too much, otherwise the battery cannot be inserted back or the frame cannot be clipped back to the phone's body. Remember that A+B resin becomes quite hard after 24 hours cure, and I'm sure you can cause the crack by yourself trying to remove the extra resin completely hardened. Do it while is still soft, like after one hour of curing, when is still soft but not stickier anymore. Place the battery back in the frame to mold the resin after the battery's corner shape. Apologies for my English, it's not my native tongue. You will understand what i mean when you have the frame and the battery in your hands.

Warning!!!!

Now, I don't recommend this thing to everyone, even taking out the frame can cause the crack if you follow the opening procedure like in the youtube video, but you start un-clipping the frame from the volume buttons side, because you create the stress that rips the frame.

It's a job for an experienced technician, or a person with some tech skills and creativity in fixing/repairing/reworking existing mechanical fixtures, a person that understands how to open a clipped casing without braking/ripping the clips. Use an obsolete credit card filed against concrete to the right thickness or a guitar pic. Using a screwdriver will dent the casing of the phone around. Try first with the remote control of your TV set, some of them are really hard to un-clip. The hardest part is the fact that you cannot repeat the procedure over and over to get used to this repair, you do it right or you screw it, one shot. And it's a shot worth 400-600 euros (or dollars...). The phone will work, but the aesthetics will suffer. I fixed mine, the crack is still visible, but the frame holds firmly now. Like I said, it's very poor design, whether is from HTC or from SonyEricsson doesn't matter anymore. I only hope they learned from this and their phones will not suffer this weakness in the future models. It's such a shame that a good hardware is enclosed in a amateurishly designed casing. Will it be possible to make SE aware of this design fault?