Quote Originally Posted by struth View Post
maybe a good clean may sort it if it happens again.
It's the first thing to try. I use this: http://www.ebay.co.uk/itm/Switch-Cle...item4198c40da4

Avoid the solvent types. They can dissolve plastic parts.

Also (as I'm sure you know), check soldered joints. Which could be a pain. As there are quite a few inside.