I just recently cleaned and serviced a 89 C and was very well pleased with how it runs and the amplitude of the pendulum. Indicating to me that it is a strong and healthy movement. So, I have an old ST with an 89 AD movement, that has never been very reliable. I tore it down and serviced it too. It does have a little more play in the bushings and could use about 3 new ones. But, I assembled the time side (which has always been the problem - strike side works great). And the train runs free with no spring. So, I put the spring in, wound it up and it still doesn't have much amplitude, and not near as much as the C movement (above). So, here's one question and would appreciate any input from others who might help me analyze this. What's the difference between the two movements, and how do you interpret the ST descriptions.