As I suspected, and you can see clearly in the attached pictures, the camera and shutter drive belts on this ARRI BL 4S had shredded and desperately needed to be replaced. Replacing the belts in these BL cameras is a monumentally difficult task. The BL 4S is one of my very favorite cameras, but it was not engineered with the service technician in mind. After coping with the many of the hidden nuts and bolts and getting to the point where the two halves of the camera housing can be separated, I generally remove the circuit boards to make access easier for myself. Then I removed the drive motor and the motor mount, and I was finally able to access the midrib where the mechanics are mounted. The main drive belt is fairly easy to replace once you have gotten to this point, but the belt that drives the shutter requires you to remove the shutter from the camera to get the belt over the shutter drive shaft. Happily now both belts have been replaced and the camera is mostly reassembled. What remains is to clean and re-lubricate the movement, check the flange focal depth, check that the camera runs at speed, service all of the accessories that go with this camera, and then finally make it available for sale. A special thanks to Paul Scaglione who very kindly sent me the new belts much faster than I could order them from Pic Design.
