Replace a Leica M8 Cracked Front Cover

As I mentioned in my previous post about my Leica M8, although I fixed it successfully, the front cover was cracked. That meant that the top cover (the one with the glass windows for the rangefinder and the shutter speed dials) was hanging on only by one screw, instead of two, and someone had glued it in place, rather than replacing the front cover. I ordered a new front cover from Leica, at about $150. Not the cheapest, but it’s cast magnesium, so the chances of welding/brazing the cracked one were near zero, at least for my skill. the following pictures show how I stripped down every single piece of the M8 in order to replace the front cover. It starts half way through the disassembly, where we left off in my other post.

Leica M8 Shutter Fault (Broken Release Lever)

I recently bought my first digital Leica: a broken (of course) M8. The camera had a “shutter fault” problem, in which the camera doesn’t seem to be able to cock the shutter and, after trying a few time on power-on, it gives up and returns the “Shutter Fault” screen. It appears to be a somewhat common problem with a magnet in the shutter mechanisms, for example here.

After working on the camera, I believe I have an idea of what happened: the camera was dropped, and part of the chassis cracked as a result. Someone else, clearly not a Leica technician, opened the camera and repaired it (with glue, lots of glue). Perhaps because of the fall, after a while an internal part broke and a piece of it jammed the shutter. At that point the owner must have got rid of it and it ended up on ebay, where I bought it.

 

 

Update: I ordered a new release lever from Leica, for around $10, and there is a plastic roller that I did not find anywhere when I opened the camera.

leica_m8_broken_release_lever_54_update
The impromptu fixed release lever, on the left, and the replacement from Leica New Jersey, on the right.

Resilvering The Leica M3 Beamsplitter

I am at the point now where I can pretty much repair everything of a Leica M3 (mostly because you can find the service manual for it AND Leica still sells spare parts for it), with the exception of the rangefinder.

The viewfinder/rangefinder assembly is the one part that not even Leica repairs anymore, they simply change the whole assembly, retrofitting M3s with the MP’s rangefinder (for more than $900). For that reason, I started playing around with the idea of learning how to fix the most common problem on the rangefinder of an M3: separation.

One of the many parts of the viewfinder/rangefinder assembly is a beamsplitter: a cube of glass with a semi-reflective diagonal that is used to merge the viewfinder’s image and the rangefinder’s patch. Cube beamsplitters are simply two triangular prisms that are glued together, and one of them is coated with a semi-reflective layer of material. In the case of the Leica M3, it seems that they used gold. If you deposit a layer of gold (or silver, aluminium, et cetera) thin enough, part of the light will go through it, and part of it will be reflected. The most common problem with M3s’ beamsplitters is that after a few decades they separate, meaning that the glue holding the two prisms together comes loose. When that happens, the viewfinder/rangefinder is unusable. The solution is to take the assembly out of the camera, and re-coat one of the prisms with a semi-reflective material, and re-glue the beamsplitter back together. Getting the beamsplitter out of the rangefinder assembly is pretty hard: whatever glue they used to set it in place is strong and did not weakened in any of the solvents that I tried, not even acetone. My suggestion is that you slowly and carefully scrape it off, using drill bits to remove it from the holes it is in.

After a few attempts, I was able to deposit a semi-reflective layer of silver on one of the prisms, and glue the beamsplitter back together. The result is NOT pretty, but it works. The hardest part of the process is to obtain a uniform layer of silver, while making sure that the amount of reflected light is roughly the same as the amount of transmitted light. My initial idea was to do the deposition while controlling the amount of light going through the prism (with a light-meter app on my phone) and stop it once the light was cut in half. This turned out to be easier said than done, and I eventually settled on a “try again” approach. Once you get the hang of it, depositing silver on a small piece of glass is done in about 5 minutes, and with a UV glue putting the prisms together is even faster. It took me about 10 tries to get an acceptable deposition of silver, and I stopped mostly because I was going on a trip the next day and I really wanted to bring that camera with me to shoot pictures. To deposit silver on one of the prisms, I used the mini-kit available at angelgilding, and I used a UV/blue curing optical adhesive from Norland, NOA85V. My tips for silvering are:

  1. Use only glassware and make sure it’s clean. I tried to use some plastic container I had around to hold the chemicals and the glass during the deposition, and I would always get a brown cast on the silver coat. When looking through the viewfinder/rangefinder assembly I would see the RF patch, but the whole image was dark and brown-ish. My guess it that the plastic the container was made of interacted with the chemicals and contaminated the silver deposit.
  2. Use a stopwatch to record the amount of time the prism spends in the chemicals. In my case I figured it took around 3 minutes and a half to get a silver coating that reflected and transmitted the same amount of light (roughly).
  3. Keep an eye on the temperature. Like all chemical reactions, temperature is going to affect the deposition rate. Instead of measuring the temperature and trying to control it, do all the tries and deposition in one day, so that you know that your chemicals were roughly at the same temp the whole time. I did my final 4/5 attempts in one afternoon, so I knew that leaving the prism in for an extra 30 seconds would give me a thicker coat of silver, cause I knew the temperature was roughly the same as before.
  4. Be patient. It’s gonna take some time, some cursing, some sweating. Be ready to be disappointed and to improvise. Once you see the pictures of my result, you’ll see that you don’t need to achieve perfection to get something that works well.
  5. Don’t be clumsy. Once you get the deposition that you like, be aware of where you put your fingers! The silver that is chemically deposited on the glass surface is VERY delicate, and just touching it is going to remove it. Do not touch the surface once you’re happy with it. No cotton balls, not acetone to “clean it one last time before I glue it”. Just use a hand blower to remove dust if you see any on it, but no physical contact whatsoever.

 

As you can see, my final result is not pretty, but when I look through the viewfinder I don’t notice the bad silver coating: that’s because the silver is not where the image is formed! For example, you will see any speck of dust that is on the frameline mask of the rangefinder, but you won’t see that big spot where I accidentally remove silver from the prism. I hope this help anyone that is trying to do the same repair.

Inside the Leica M3 Take-up Spool Shaft

The Leica M3 doesn’t have the quick-load feature of later M models, and uses a removable spool to load film. You first put the film leader under the take-up spool spring, then the take-up spool goes in the camera, alongside the film cartridge. When you remove the take-up spool from the camera, the film counter resets. This happens because thanks to the mechanism that is inside the shaft where the take-up spool is inserted. The pictures that follows show how to take this shaft apart. Note that there are several slightly different versions of the Leica M3, so yours might be slightly different than mine.

Inside a Leica M3 Shutter Curtain Roller

Have you ever wondered what’s inside an M3 shutter curtain roller? It’s a simple spring, the one that you can regulate when you remove the Leica M3 bottom plate. I am completely dismantling an M3, and I opened up the roller of the 1st shutter curtain to see what’s inside. As you can see, the grease in there is completely dried up. I don’t know if the rollers get a lot of cleaning usually, because removing them is a lot of work.

Replace the film take-up spool of a Leica CL

Leica CLs have a plastic take-up spool that is prone to breaking. The following pictures guide you through removing the white part of the spool, the one that usually breaks, so you can replace it with a new one. The following images start with the bottom plate already removed.

Inside a Leica CL Metering Device

The meter needle of my Leica CL wasn’t moving at all, so I decided to take it apart and see what the problem was.

As it turns out the metering device, a galvanometer, is broken. When measuring the resistance of the coil, which should be around 3.8kΩ, I get an open circuit. This means that somewhere inside there is a wire that is disconnected, and I decided to take the galvanometer apart and try to repair it. Here are some pictures of the disassembling process and of what’s inside the galvanometer.

 

The whole process is a delicate and painful one, unless you own a stereo microscope and a good SMD soldering iron. If you contact Leica they can send you the spare part, but it takes 3 weeks to come from Germany (they don’t repair Leica CLs in  USA) and it costs more than $80.

Taking a Leica M3 apart

I got a used M3 off ebay a few months ago and I fixed it. There are a few websites and youtube videos that show how to open an M3 and fix some issues it may have, and there is also a service manual for the Leica M2 (which is very similar to the M3) .

Here are some pictures that walks you through taking a Leica M3 apart, with some comments on the tricky steps.

Adjusting the shutter slow speeds of a Leica CL

If you ever wondered how the slow speeds of a Leica CL works, here is a picture of the internals after removing the top and the front plates:

without_springwith_spring

In the red box is the slow speed escapement, namely the mechanism that counts time between the opening and the closing of the curtains, while the green arrow points to the lever that transmits the speed selected by the dial.

Removing the selection dial helps understanding how the lever translates the speed information from the dial to the escapement.

lever

The lever, now visible in the red box, pushes the escapement up and down, effectively changing the shutter speed. It is unfortunately impossible to describe this beautiful and ingenuous mechanism in few words, suffice it to say that the speed of the shutter depends on the up-down position of the escapement.

Since the position of the lever determines the slow speeds, and considering that the escapement might change its timing characteristic over the years, it would make sense if this lever were adjustable. And of course, it is.

Removing the screw that holds the lever in place reveals a neat feature: the lever rotates on an eccentric pivot:

screw

Turning the pivot with a screwdriver will change the position of the lever, hence changing the position of the escapement with respect to the shutter speed dial.

Of course, you don’t need to take your camera apart if your slow speeds aren’t what they’re supposed to be. The pivot is easily accessible from the back of the camera, next to the film spool.

pivot

Taking a Leica CL apart

I recently bought a Leica CL camera on Adorama for $125. The camera had the following issues:

  • Unreliable slow shutter speeds
  • Loose rangefinder window’s glass
  • Stuck ASA (film speed) selector

I decided to try and fix the camera myself, and since I couldn’t find any information online on this particular camera, I am posting a few pictures on the internals.

Hopefully this will help some of you to safely take your camera apart and repair it.