Zeiss Ikon Nettar Shutter Release Repair
I acquired this camera last Christmas (2013) and found that there was a problem with the shutter release. The shutter didn’t remain cocked and, in fact, went into a semi released position with the shutter open. The whole linkage was jammed at this point so I had to hold the shutter in the fully cocked position and then use the release linkage on the shutter assembly itself to trigger a full release.
I realised that I would have to take the thing apart to see what was wrong and it would have been really good to have a service manual for the camera as a guide. As I didn’t have one, I had to take it apart blind and work out what everything did so, having done it the hard way, I’ve posted this for the next person with the same or a similar problem.
My apologies, by the way, if this post is a bit simple minded, but I've assumed that whoever reads is about as ignorant as me. Also there are probably more photos than strictly necessary for the same reason.
Step 1: Removing the focussing front lens element
To get into the shutter assembly, you need to remove the front (focussing) element of the lens. This is kept from unscrewing by the stop screw you can see between the F11 and F16 positions in figure 1. Unscrew this and the front element will screw out. Don’t mess with the other grub screws around the lens. They fix the relationship between the distance scale and the lens position and you’ll have to reset the focus if you lose this. Screw the front element out, counting the number of turns so that you can get it back to the same position when you put the stop screw back. Be careful not to get dirt, grease or finger prints on the lenses.
Step 2 Remove the retaining screw ring
With the front lens removed, you now have access to the ring that holds the covers in place over the shutter assembly. Below the lens opposite the F22 marking in Figure 2 you can see the locking screw that keeps the retaining ring from moving. This doesn’t in fact screw out. One side of it is flat so you need to turn it so that the flat side faces the retaining ring which can now move past it. Now carefully unscrew the retaining ring. Ideally you will have the special tool for this but most of us will just use a screwdriver to push the ring round until it comes off.
As you can see from Figure 3, I wasn’t the first person working on this camera who didn’t have the special tool.
Step 4: Remove the Depth of Field and Shutter Speed Rings
Once the retaining screw ring has been removed, the depth of field and shutter speed rings lift off. Figure 4 records how the shutter speed ring is mounted.
Figure 5 shows the exposed shutter assembly
The shutter release assembly is to the left of Figure 5. It
consists of 3 sections:
1. The ‘B’ time exposure group held by the screw next to the lens at 10 o’clock
2. The release linkage held by the screw at 8 o’clock – again next to the lens
3. The actual shutter catch/release held by the screw at the outside at about the 10:30 position
These need to be kept separate when disassembled and Figure 6 shows the containers I used to keep the three sets of components.
Step 5: Remove the ‘B’ Time Exposure Group
To avoid the risk of having everything spring off the table and get lost when you take the screw out, unhook the bottom end of the spring. Then undo the retaining screw and remove the ‘B’ group. Figure 7 shows the components in order, screw then spring, under that the ‘B’ stop and then the bottom linkage. In this camera, the shutter cocking lever had been forced back and the linkage was slightly bent, so needed to be straightened.
Figure 8 shows the shutter assembly once the ‘B’ group has been removed. Note that the spring on the shutter release has already been slackened off at this point.
Slacken off the spring on the release linkage by lifting it off the hook at the outside of the case (about 7:30 o’clock) and then remove the screw linkage and spring.
Note that the spring is beneath the linkage as shown in Figure 10.
Step 7: Remove the Shutter Release Catch
Figure 11 shows the shutter release catch once the release linkage has been removed.
At this point it is possible to see that the catch on the lever has been bent flat as the cocking lever has been forced closed. Figure 12 shows the cocking lever held back with the release catch ready to engage. The flattened catch will not keep the camera cocked although it still interfered with the complete release of the shutter.
Slacken off the spring and remove the screw, spring and lever.
Figure 14 shows the situation once the release group has been removed. Notice that there is a detente in the case below and to the right of the release group where the cocking spring will remain, simplifying reassembly. And the spacer has not been removed in this photo.
For Interest: Repair to the Release Catch
Figure 15 shows the bent lug on the release catch.
Straightening this showed that the lug had been seriously cracked and weakened as shown in the left picture of Figure 16 so I used a fillet of solder to reinforce it as shown in the right hand photo.
Step 8: Remount the Release Catch Group
Reassembly is a reversal of the dismounting process. Note that both the release and ‘B’ Group springs will pass over their respective screw heads so it is best to screw in the other components first and make sure that they move freely before adding and tensioning the springs.
Figure 17 shows the release catch in position engaged with the shutter cocking lever. Releasing the catch triggers the shutter. The shorter end of the spring is nearer to the cocking lever.
Step 9: Remount the Release Linkage
The release linkage spring is mounted below the linkage itself, so the spring needs to be on the shaft with the kinky end engaged in the detente on the underside. The protruding tail of the linkage itself has be slid in below the trigger from the camera body. This is a bit fiddly but once the linkage had been screwed in place and is operating freely and activating the release catch properly the spring can be tensioned. Figure 18 shows the release linkage remounted.
Step 10: Remount the ‘B’ Group
Remounting the ‘B’ Group is a reversal of the disassembly process. It’s easier if you do the spring last once you have both the other components screwed in place and moving freely. The ‘B’ stop has to be on the lens side of the linkage pin. Figures 19 and 20 show the group with and without the spring.
Step 11: Reassemble the Control Rings and Lens
Refit the shutter speed ring as shown in Figure 4, positioned to the ‘B’ speed setting to ensure that the control lug is engaged. Add the depth of field ring, screw on and lock the retaining screw ring.
Clean any dust from the lens area and screw on the front focussing element of the lens, counting the number of turns to ensure it’s back in its original position. Check that the focus range is correct and replace the stop screw.