Hello. I am lucky enough to own an antique 36 hour, chain wound, whiteface, longcase clock. It stood in our kitchen for over 20 years and began to stop at random times, as well as mostly not striking. We diagnosed that it needed cleaning and oiling, which has been done. It now runs beautifully and strikes every hour on the hour. BUT, it stops every three hours, to the minute - well sometimes it manages 6 hours, or even 9 hours, but you get the idea. This happens regardless of what time it has been started. When you come to re-start it, by swinging the pendulum, it doesn't begin ticking unless you gently pull down on the weight or give it a bit of a shock by winding it or getting it to strike. Any suggestions would be very welcome.