One thing I should have added about the Yashica restoration … stuck shutter button.
Now it is not a difficult thing to pour Ronsonol around the shutter button to free it from being pressed down … it is another thing if the shutter button does not come back up. This requires getting behind the front panel.
There are three levers that push against the shutter release button.
The first lever pushes against two others. In the picture, look at the bottom section. The farthest left lever trips the shutter, the furthest right releases the winding mechanism (note that the shutter button lever is in the middle … I forgot this part and could not understand why the cover with the shutter button could not be attached properly.)
If these levers are gummed up they will not move freely. To clean up the crap you need to take this apart and clean it.
First remove the upper spring from the large cam so you do not stretch it.
The light baffle ring behind the lens just unscrews counter clockwise.
After that is remove you can clean up.
When putting it back together, remember the shutter button lever is in the middle.