Bob, I meant the cover that the handle is mounted on. IE: The whole box cover!
If a plate inside the box had sheared off it's mount on either the base or the end of the handle. You WOULD get a complete circuit ALL of the time. I have had this happen to me. It APPEARS to be working manualy, BUT, inside the control box it is STILL conected!
Chris makes a good point with regards to new boxes on Ebay. If your restoring, this would be a better prospect. Time saved in stripping cleaning & reassembling would be saved. & add to that, it would probably outlast you! :-D