try "gently" tapping the cover off with a rubber mallet, but if you feel resistance, stop!, you'll need to figure out what's holding it from coming off.
I don't think there's many guys on here that have 60's, I've never opened one up, but can't see it being much different than a 125, 250, or 500.
maybe there's someone on here that has opened one up that'll chime in...if not, I strongly suggest finding a manual.