Hi. It seems you got the same problem as me. There only few solutions you can do.
One of them is cleaning. Take a toothpick or a small nail and put on few drops of pure spirit (or use pure vodka) (ATT! do not use any sugar or water containing liquid. With sugar ( sweet and stinky) you gonna make it even worst. With water - short circuit.
So, take a toothpick with spirit on it and clean the plug.
IF this one wont help you : there is another way.
Go to ebay.co.uk and search for k750i plug and order it. Using stun u can fix it. Or ask service center to fix it for u.
good luck
EARNEST
August 2007