check the fuses on the top of the batt, the 3 green ones....

think it was the middle one cos on mine it had not burnt out but the contacts had gone grimey
give them a wigglt first with it all on and you may find it comes on.. this is what i did and it worked a couple of times but then just cleaned it up the contacts... good as new

(also prior to this i had it re-gassed cos i thought it was this but when they took the gas out first it was full - so no charge!!!)
