Pentax 67 Shutter Trouble

[MarkPeeters]

I have a Pentax 67, but the shutter seems a bit all over the place. Just shot a roll of film which every shot was at 1/1000. some frames were all blank, some of them were perfect, some of them left half of frame fine, other right half under exposed.
I will try out some other speed settings to see if all of them are affected. Does anyone know why this is happening, and perhaps how to repair such issues, or point me into the right direction?

 

[shutterfinger]

The camera needs a CLA. The focal plane shutter uses 2 shutter curtains, At any speed setting the first curtain starts moving across the frame then the second curtain starts moving across the frame creating a slit that moves across the frame. The speed selected determines the width of the slit. At 1/1000 second the slit is its narrowest. Blank frame is the second curtain releasing with the first, partial frames is the second curtain catching up with or separating from the first curtain part way across the frame.
The curtains have a fixed speed that they run at and are likely not running the correct speed also.