toast on off button is intermittant.

Alas, his problem is not with the power switch, but with the "toast" switch. Unfortunately, that is a membrane switch. I've never seen any indication that these are repairable. Panasonic's parts outlet does not include the membrane panel as an orderable part, so I think Richard is out of luck.

I had the same problem, these are not membrane switches but small clicky type switches soldered onto a printed circuit board.  There is a flexible plastic lever arm which pushes against the clicky type switch, all it needs is a very “thin” shim underneath the plastic lever arm to activate the clicky type switch. My final shim was a bit thinner than the thickness of a fingernail.  Heat gun helps soften the plastic when cutting and trimming the shim.  Used bent up paper clips to maneuver the shim into place and slow setting glue as it required many attempts to get the shim the right thickness and positioned correctly.

When disassembling the electrical components be gentle and careful, plastic is brittle and breaks easily.  The spade/blade type connectors have a small button which must be squeezed to release them, tricky to do with fat fingers.  Take pictures as you go along so everything gets put back together correctly.  Good luck and have patience.