Problem with fed 4 and film developed results

Goodmorning everyone. I'd like to ask for a consultation to help me understand what may have happened to the film I just picked up from the lab. I took 24 poses with my fed 4 which I fixed and am trying to see everything work. All 24 poses were successful. The problem I found is that only the first shot is developed in its entirety. From the second shot to the last half of the exposure is visible, while the other half is completely black. it could be that for the second shot I have loaded the film too little and consequently I have out of phase all the count of the following shots? Or is it a shutter problem?

Shutter problem. Your second curtain is catching up to the first ("capping"). Since it doesn't look gradual, and worked on the first frame, it's likely some obstruction (film chips are famous for doing this, but it could be a loose part from recent work, too), either in the shutter track or in the drive mechanism, is causing the first curtain to hang partway. If you open the camera and fire the shutter on B (so the second curtain holds until you release), you might be able to make a slow motion video with a smart phone that will show this happening.

Donald Qualls said:

Shutter problem. Your second curtain is catching up to the first ("capping"). Since it doesn't look gradual, and worked on the first frame, it's likely some obstruction (film chips are famous for doing this, but it could be a loose part from recent work, too), either in the shutter track or in the drive mechanism, is causing the first curtain to hang partway. If you open the camera and fire the shutter on B (so the second curtain holds until you release), you might be able to make a slow motion video with a smart phone that will show this happening.

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I checked the shutter without film and without lens and it works fine. may it be the fact that the curtain had a hole and I fixed it with glue as I read in a forum? now at that point the curtain is a bit hardened and bent but looking at it doesn't seem to touch anywhere.

If the first curtain hesitates even a little, the second curtain (if already running) will catch up a bit -- and the slit on horizontal shutters is usually quite narrow at fast shutter speeds (as you'd commonly have outdoors in daylight with fast film). The shutter movement is too fast for most people to catch a snag like this, though if you set the speed to maximum and hold the camera in front of an evenly lit surface, you might see it as a darker area on one side. It's also possible, if this was caused by a film chip or something loose in the mechanism, that the cause has moved, either completely out of the camera or into a less troublesome location.

If you have a digital camera or cell phone with long exposure capability, you could make a long exposure to verify that the fastest speed in the Fed is working correctly now, then try with another roll of film.

Iodosan said:

I checked the shutter without film and without lens and it works fine.

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With what speed you checked it?

Half of the frame never receives light so you have a problem in the shutter for sure. IMO Donald is well right...

You may use a modern smartphone at 960 fps to see what happens.

Donald is spot on, problem is with the shutter, I have seen this often with FSU cameras, you can get a slightly lazy shutter, and the second curtain catches up with the first, and only part of the frame is exposed

R.Gould said:

Donald is spot on, problem is with the shutter, I have seen this often with FSU cameras, you can get a slightly lazy shutter, and the second curtain catches up with the first, and only part of the frame is exposed

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The problem was the shutter. Thank you guys. The curtain with the repair was curved and then catched up with the first. I tried to lift the glue and I used another type (some shoes Black glue). I will put a film and you will know if is it working. Thanks a lot guys for your time!