iPhone 3GS randomly vibrating & turning itself off silent and I don't know why!

[GeetTallBird]

Any advice? My iPhone 3GS is ancient, still love it though, but it vibrates for no bloody reason!
If it's upright it's usually ok, but the second you tip it back or lie it down it vibrates and the silent and non silent logo keeps appearing and swapping on the screen!
Having it in my handbag makes it vibrate the whole time I'm walking too.

Think it's an internal balance issue??

Mine did that. I think it was problem with the toggle switch, which is quite well documented.

You can have it repaired, if you want to hang onto the phone.

Thanks for replying...I've seen it well documented, you're right, just not seen a cure!
Off to phone shop to see if they can repair....