Lu,
The signs of overheating that I referred to are localised hot spots on the rejected pivot pin. They occur in a random pattern and are associated directly with worn areas. It isn't clear if they precede or are the result of the wear. So far the redesigned pins and bushings appear to be effective although the trial is still in the early stages.
It occurs to me that some readers may find this discussion alarming. Please be aware that although this subject concerns a serious problem, the problem is identified, under control and the follow up described is just normal engineering activity. The daily routine for those working in Tech Support and Maintenance, in fact.
**********************************. .Through difficulties to the cinema