Fixing slow shutter speed problems on a Miranda Sensomat

I have recently been increasing my collection of Miranda vintage cameras and along with a few other models I’ve acquired two Miransa Sensomat RE models and both of them had the same problem – at slow shutter speeds (i.e. between 1/8 and 1 sec) the mirror flips up but the operation didn’t complete and the mirror is left up and the shutter open.

What I found is that the shutter mechanism was basically dried up and sticking and this is a brief post to explain what I did to fix it.

First you need to remove the bottom plate of the camera. This means first opening the battery compartment and then removing the 4 screws which hold the bottom plate in place.

This reveals an electrical board on one side of the camera and a mechanical arrangement on the other side. The mechanics are the escapement mechanism for the slow shutter speeds. I found that when the mirror was locked up I just needed to touch one of the arms and the operation would complete and the shutter fire. So I applied a very small amount of thin oil to the cog wheels in that area and fired the shutter a few dozen times to work it in. Once that was complete the shutter seems to reliably fire on all speeds.

Camera upside down

Remove the battery compartment lid

Remove the base plate

I applied a very small amount of thin oil on these brass cogs

And a small amount on the screw/slot arrangement on the left here

Just a word of caution – it is very easy to go overboard and apply too much oil. I have a small Draper oil pen which applies a drop when you depress the knob on the top and I used that to drop a tiny amount on one cog and then used a tiny screwdriver to distribute it to other parts.