They look complicated when you see it for the first time but I personally don't think they are, even so I would only do minor repairs on mine. I know people say they are a finely tuned machine but when I read in the service manual to bend the lever to adjust it they lost me.
They're the most complicated cameras I've worked on. You have to remember, the shutters and timing mechanisms are located in the lenses. Even then, the bodies are quite complex because they have to sync shutter in the lens to the mirror to the rear shutter to the film back. And the gears need the proper type and amount of lubrication to keep everything in time, as they operate on mix of spring torque against drag. Too much torque, and the rear shutters bounce back to close. Not enough, and they don't open fully. They're not like 35mm SLR's were all of the mechanics are housed in the same body.
They're finely crafted machines for sure. But they're not like an Argus C3 that you can bury in the mud and pull out ten years later and still have it work (only slightly kidding). It's easy to ruin something and hard to find replacement parts for cheap.
Anyway, I'd suggest having it professionally CLA'd. These cameras tend to need regular maintenance (once every ten years or so) and many have seen heavy use in a past life(many were owned by professionals who took hundreds of pictures a week with them). So consider the occasional CLA the price of ownership. It's like I say, they're like classic sports cars. They're very well made and complex pieces of precision engineering. They're not like the old Nikons or Pentax's which are more like Hondas and Toyotas. Those cameras can often run for 40 years and need nothing more than some new foam.
Still, there's a screw on the front of the camera behind were the lens mounts on the bottom. You have to access it through the rear shutter. You can try turning that to unjam it. They sell a special tool to access that screw for when it came in the field. You can use a small Jewelers screwdriver though.
