One of my (upright, 17 y/o) freezers has started condensing water onto it's top surface (thereby destroying the two boxes of clay pigeons on top of it - grrr). I've defrosted it this afternoon and it now seems OK, but could it be that the insulation has failed? (This happened once before on a tiny chest freezer we had).
If it has, is it repairable? The freezer works fine in all other respects.