Answer to "ipad 4 gets always in dfu mode"All apple products will go into DFU mode with different button sequence attempts. So the only way to get the ipad out of the DFU mode is to connect to itunes, hold down power button and home button only. It needs to connect to itunes and perform a soft reset to get back to normal. As soon as you see the apple logo flash once let go of buttons so it doesnt go into restore mode. Hope it helps!
Answer to "Will not turn on just vibrates every few minutes"Have you tried to do a soft reset or enter recovery mode?