I have the same camera that had the same problem, shutter/film advance locked up, and mirror locked up also. Since a coworker gave me the camera for free I felt there was no point on paying $50 or $100 for a CLA, right? So I researched for days online and found 3 potential basic problems for this camera. From problem A the easiest solution to problem C the most complicated. It turned out that by placing a butter knife into the curtain and helping it to wind in the same direction the curtain moves the whole thing was supposed to go back to normal. I did that and it worked, then it got jammed again in a different day and I tried one more time push the curtain with a finger and place a knife to reach one end of curtain and release curtain helping it to wind in position. Camera works fine (cross my fingers)
Where did you find the info on the butter knife trick? I have 2 X-700's that are locked up. Specifically how do you insert the knife without damaging the curtain?
I bought both cameras 20+ years ago and they both locked up within a week of each other.