Documentation and experience count for a lot when taking apart a camera. The Canon 7 finder is much more complex than the Canon P, getting the top plate back on can be a trick. Working around the meter, getting it all back together without knocking the meter off and causing the shutter release to jam up- takes a lot of time. Took me a long time to figure out why the shutter release would not work WHEN the top plate was back on. Turned out that the frameline selector had not fallen exactly into place. Then had to "recalibrate" the meter. Took a couple of screw-ups to figure it out. Then, unless oyu do it often- forget the lessons learned. Canon 7's are going for cheap these days, and a pro would have to charge a fair bit to work on one. takes longer than the P.