does not switch on

No power? If this is the case and you know there is a charge, you can try and fee things. I would try a hard reset. This solves most problems. Hold home button and power button for at least 30 seconds. The Apple logo should appear. If that doesn't work, try to plug into iTunes to see if the computer recognizes the device. The last thing would be to take to a service professional for repair.

Please be advised that myself, nor this web page can be held responsible for damage to any device, should an attempt at repairing one's own device fail. Always make sure to consider hiring a professional repair shop to fix your device for you.

There are plenty of reasons the device will not turn on. and a lot of my customers also say it won't turn on, when they are just not getting an image, and the device is actually booted. please do what is listed below in order to fix the issue.

First thing you should always try was stated above by @theiphoneguy07 where you should make an attempt at the hard reset. I Find 30 seconds is a bit of overkill, and usually get a reaction from the device within 15, but 30 is more safe, JUST in case. If you see the apple logo, then it worked. If not, continue.

Next, plug the device in, and let computer look for drivers for a couple minutes. if you havent plugged it into your PC yet, it will say "Installing device drivers" above the right of your taskbar. if you have, the easiest way to see if the PC recognizes it is if you have itunes installed, then to see if it picks up the device. IF it sees your device, you may be looking at an LCD Replacement.

if you plug the device into the cord, Normally it boots. so if it is fully charged, you should be able to have some way of seeing this. if you don't have a visual of the charge, then you have no way of actually knowing that it is charged, and it could even be not charging. in which case, i would do as follows.

Diagnostic steps for not charging:

1) Check for a blocked port (Lint build up can keep a cord from fitting in properly. if the frame of the plug is not flush with the device, using small tweezers, and being careful not to damage pins, pry out any dust or lint.

1) Try a Known Functional Cord. (Works on another device)

2) Excite the battery: Hit the + and - of the battery with an external power supply for approximately 10 minutes. (Be sure to verify you are using the amperage and voltage that the battery can handle. (Located on the battery with the specs.)

If the device boots, then the battery is functional, and you can continue forward with your diagnostics.

3) Scan board, and Flex circuits for physical damage. Looking for signs of blown or chipped components. Scorch marks, or corners of components broken off. Replace as needed, and test again. A 10X+ microscope assists very well in this stage

4) at this point, plug in the device again, and check if it charges. if it isn't, then go forward with replacing the charge port itself.

5) if replacing the charge port does not fix the issue, then you are experiencing an IC or board failure, in which case, it will just be better to replace the device.

I hope this guide has helped you in your diagnosis.