[tuyauxtu]

Al
I would say that at the time, tapping the breaker made it worse which made it untrustworthy. Would not say that it was the open button but it may have been. The breaker at the time was horizontal (facing up) and solidly attached to our protobot's 1/8" holey aluminum belly pan. We though initially it was a loose stud electrical terminal contact. Once it was apart, I slid a piece of paper between the contacts and it was gripped fairly well, however it came out with a very, very small amount of 0.5 mm wide grey streaking from the top contact and a wider (0.5 cm), darker streak from the bottom contact, indicating to me that the contacts were not absolutely clean.
I just put it back together (with bolts replacing the rivets) and when electrically closed the red button is loose (it looks like there is about 1 mm of travel before it contacts the rubber gasket). It shows about 0 ohms on a cheap DVM (accounting for lead resistance). I bumped the breaker a lot and it stayed closed, but what seemed to me to be a light touch on the open button caused it to open then close then when the force was removed. The kitchen scale tells me it takes about 400 grams of push to break contact, so roughly 14 ounces (it takes about 1300 grams, 2.8 pounds to start to move the lever out). Do not have another handy to compare it to.
I do still have it. Let me know if you want it sent somewhere, or brought to IRI.
Thanks to Phil for posting the link.
Pat