I posted on the internet, way back in 2001, the following diagram. Here i indicate the exact point where, by just spraying some drops of WD40, the squeak would be solved for years. Did it to my A-1 with no problems at all way back in 2001, the camera still works as today.
Yes, it is just caused by lack of lubrication on a specific flywheel. On the GIF above I indicate the point where the mechanism can be easily re-lubricated, using a common WD40 can, the one that comes with the straw. WD40 is a mix of kerosene -which will loosen the gummed-up lubrican, and very light lubricant.