i suddenly have no sound on my ipad. it works on facetime but that is it, i don't hear anything from youtube, the music app or even the sound of the keyboard typing. i'm not in mute or anything. i have reset it twice but no luck. when i swipe upwards into the control center there is no volume bar like there would usually be, however when i facetime someone and then look in the control center the volume bar is back.

all sounds work when i use earphones and i have tried taking the earphones out and back in again several times but that hasn't worked. the weirdest part is that if i plug the charger in the volume bar comes back for about 3 seconds and disappears again. same thing happens when i take the charger out. i have brushed the charging port with a toothbrush for ages to see if i could clear some lint or anything out but that hasn't helped either. any ideas anyone?

no help, but that is very very strange. Not sure they could help, but are you close to a Apple Store?

Just a quick one to try, did not see you mention it above..
Have you tried toggling the iPad side switch.

These iPad models have a Side Switch on the upper right side of the device, above the volume buttons: iPad Air, iPad 2, iPad (3rd generation), and iPad (4th generation) iPad mini, iPad mini 2, and iPad mini 3
You can set the Side Switch to lock the display orientation or mute certain sounds.

With that switch in mute mode, you will get a mixture of certain sounds coming through but not all.

I have also seen on an Apple support forum thread a suggestion that even if the switch is configured to Lock Orientation mode it can still screw up the sounds. The posts go on to say that going into the configuration settings and changing it to Audio Mute then operating the switch a couple of times might restore sounds.

Mind you a lot of posters seem to be saying that only a full reset back to factory defaults sorts it out. Which of course will wipe any personal data that has not been backed up to something like iTunes.