Just warm it and with a razor(razer? you know the sharp flat knives ;D) you cut along the edges.
Just make sure you move the razor parallel between the touchscreen and display, so you dont break or scratch the screen.
For heating up, you can take a hair dryer or put it in the oven for 5-10min. I think 50°C(a bit longer to heat all trough) . More temperature shouldnt be a problem, sun on black surfaces often gets ~80°C but dont risk it, and you need to touch it to remove the screen
For the soldering version a little hint:
The cable on the new touchscreen can be soldered from top and downside.
You dont need to solder on top the little overhang, just put a bit soldering tin between, then cable on top and let the heat go trough the cable to heat the tin on the underside=> more space and all the way conected.
There is a little round mark to alighn the new cable. Use this, or the chip on the cable will not fit unter the hole in the housing ;D
If its hard to solder just put a bit soldering tin on the display first. Then put the cable above and press the soldering iron on top. The soldering tin you put between will connect them perfectly. Use a tool to press the cable on the display untill the soldering tin is hard.
The secret of basic soldering skills is not to move after you take away the soldering iron until the tin is hard, every movement in these seconds makes the soldering spot weak or its not connected right.
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