Hi
The slow speed logic is in the shutter crate and you will need to remove, the top embillisher plate (chrome), the top plate, and then the shutter crate.
All simple to do, small number of screws, none spring loaded...
There should be enough free wire to leave the flash synch c0nnection intact...
Normally the problem is grease turned to gum/rubber, and Zippo dripped from separated tweasers on each escapement/moving part should do. Dont use force as much if the logic is wristwatch style cogs/controls.
Ive not hae a speed selector jam but it is possible... normally the wind on is frozen.
The shutter module will stay in one piece if you are careful, but please heed Russ advice about keeping it that way. (add another 3 hours if you neglect ths)...
About two hours to remove the module and reassemble if it is only zippo you need. Add very fine sewing machine oil to any moving parts zippoed afterwards, most will run dry so dont use much. Hopefully nothing is broken...
Noel
P.S. The light sealing under the tip plate is marginal, and I normally add black plastic and black foam under the plate to ensure 100%, performance The light can leak into the sprocket shaft and up to film. Just gloe in more dont move or adjust anything, some bits need to move.