Technics SL-P555 won't turn on

I think I've just made a massive mistake with my Technics SL-P555.

I finished getting it up and running by installing a new tray belt, all was well, before I went to remove the top cover with the unit still powered on, and it died.

I've checked the fuse, replaced it anyway. No dice.

I've obviously made a major mistake by removing the cover whilst the unit was on.

Can anybody help?