[HTC One X] hamdir:
Ok I promised some of you to write how to test the One X quickly for possible defects

First

- check the list of possible defects: http://xdaforums.com/showthread.php?p=24516940#post24516940

- The most widely reported defects are between HT23 and HT242, anything above HT24D (mid April) should be newer, check how to figure the batch date in here: http://xdaforums.com/showpost.php?p=25872020&postcount=17

Before you turn it on

- Test if the screen's gorilla glass has lamination or fitting defects, run around the edge of the glass and make sure its all fit, not loose or flexing in any side or creaking bad, there shouldn't be a large gap between the metal rim and the glass, one side might be fraction larger than the other but anything bigger might be worrying, if a very slight creak happens in one corner it might be ok, you will have to judge it yourself, the screen has to feel rigid all around, the most important is the left and right sides they should look flawless like this and this

- Run around the metal frame around the screen and check for any gaps between the metal frame and the unibody

- Check if the metal frame around the screen has clean glossy coating, sometimes it comes with very coarse coating, its best tested by looking at reflections, it looks very cheap like this

- Check the unibody frame and the matte coating, whether the quality is to your liking, the straight line in the glossy side is normal its in 90% of them

- Check the camera if its not too off center, rattle sound on camera shake is normal

- Check if there is dust under the screen while it's off

After you turn it on

- Run your finger and gently press around the screen edges, the LCD should not ripple unless pressed hard intentionally on the outer edges, any ripple in the middle of the screen and or easily triggered ripple from the edge or corners is a defect

- Go to a dark page and make sure there are no dead pixels in dark areas

- Go to a white page and make sure there are no black dead pixels or scratches under the screen, then check at angles and make sure there are no hot white spots/pixels, double check so you won't regret, example here and here

- Check for yellow spots keep in mind they might go away or return, very bad yellow spots are usually a sign of bad screen lamination

- Check for uneven yellows in white areas, keep in mind it might go away in a week of use

- Many of the units have a grain visible in whites at angles, still unconfirmed if it reduces with time, double check to see if you are ok with it like here, update: been seeing this in so many laminated devices like the iPhone4 i think its normal

- Go to the gallery and test the snow plus sun image, leave it paused for view seconds and double check if there is repetitive brightness flicker, check at full brightness, low brightness and auto brightness, keep in mind a slight one time brightness adjustment is normal on Tegra3

- Early units had a jumping screen image so double check

Once you are done checking the screen

- Go to phone and dail *#*#3424#*#* and run the HTC test app

- Run the LED test and check they are working properly and check they are fit well they should light inside one of the micro holes and not misaligned

- Run the G-sensor, light sensor, p-sensor and backlight tests

- Run as much of the other tests as you can like vibrator, flashlight and camera tests

- Keep ind mind green corruption glitches in the video app, camera and browser are due to drivers in the included 1.26 software it was solved by update 1.29, so don't panic if you encountered those out of box

- Place your Simcard and make sure SIM is working by making a call, turn on wifi and bluetooth to test them, 3G and GPS

That's it, its a flawless One X, hopefully :)

Feel free to ask me for any clarification