I guess you cleaned the battery terminals good.... I have had to take the machine all the way apart before to get at the 2 springs inside that the battery contacts and clean them off. It seems when the machine wont turn on intermittantly or shuts off by itself, it is usually poor contact between the battery and the machine. the lower rods and arm cups on my machines have broken more times than I can count. I just get some fiberglass cloth, epoxy resin and repair them - better than when they were new. Take care and good luck with your machine, Mike.