Mamiya 645 Super: Shutter Removal and a Damaged Curtain
Originally posted on Instagram. Notes from the repair bench, kept here as a searchable archive. View the original on Instagram
A little technical info on the Mamiya 645 Super.
Photo one shows how the shutter unit is removed from the back of the body. This particular shutter had damage to one curtain as seen in photo two. Looks like something pointed was stuck into the closing curtain. With this sort of damage the curtain will need to be replaced. In any case, the shutter has to be taken out to this point to properly clean/lubricate the rollers before calibration.
The third and fourth photos show the shutter removed and how it is a modular unit with the curtain assembly and the shutter assembly. The fourth photo shows the shutter assembly removed from the curtains and also the moving coil has been removed in this case.
Another thing that may be of interest: photo five shows a close up of the circuit board and this tells me a couple of things, namely that this is number two version of the board (there were three versions) and that this camera has likely never had service at Mamiya. My guess on the no service is that the resistor R8 (marked 152) that is located to the upper right of the red diode has not been replaced. This resistor, originally 1.5K in value, was replaced with a 5.1K resistor whenever the camera was serviced. The original resistor would often cause the FE401 AE prism (made for the PRO model) to give incorrect shutter speeds. While the FE401 AE Prism is sold as working for both the Super and PRO, if you have problems with the shutter speeds (defaults to fastest) on your Super, this may be the issue.
Final bit of triva: These cameras were made for working professionals and often used with flash. If the shutter speed dial moved off the 1/60 setting on a job, that could be very bad. So, a modification was offered by replacing the shutter dial support with a modified one so that not only was AE lockable but also 1/60 speed. The last photo shows the shutter speed dial disassembled a bit and I have placed one of the modified parts by the focus screen so that the extra locking notch is visible. I have not been requested to do this mod for decades!
