GS645 folder linkage?
I've had constant problems with a GS645 folder. It was supposed to be in excellent working condition but the linkage was very sticky.
I used a cotton swab and lighter fluid to try to clean old lube off of as much of the mechanism I could reach without taking it apart and that helped a bit. Then I decided to try Dri-Slide, a product for lubricating guns and bike cables. This stuff goes on wet, but then the carrier evaporates and leave a slick moly disulfide dry lube. Unfortunately I came up dry <hah> in my search to get some locally. None of the bike shops or gun shops had it in stock.
Ultimately I tried some stuff called Gunslick from Outers. It is a light grease that is loaded with graphite. I used a toothpick to place tiny amounts of it wherever I could reach sliding parts in the shutter release mechanism. It seems to be helping. I managed to trip the shutter over 100 times (yes I counted) without a hangup. I'll try dry firing the camera sporadically for a little while before I commit more film to the experiment.