the most common problem is the machine is kicking the reels before the reel index arm is fully retracted.
look on the right side of the reel mech at the back/bottom and there is an L-shaped "stop" bracket. Loosen and nudge the bracket a little towards the front of the mech. Typically the right edge of the bracket is aligned or a little left of the edge of the frame.
if you move the bracket too far to the left, the handle bottom out and you're stuck. If that happens, you can reach in with a long dowel/screwdriver and push the pawl that is hitting the stop bracket to kick off the reels.
while it's never happened before, you may find info in
https://bingo.cdyn.com/slots/windup_and_kick/ useful.
there's also poorly edited (i.e. not at all) video in
https://bingo.cdyn.com/slots/videos/ ... see How_reels_spin.mp4
paperwork for some games is in
https://bingo.cdyn.com/slots/if you really have a 1090-18 (vs. just the serial number plate from one), the paperwork for the 1090-1 will be close. My docs say the w-1046-1857 schem you'll find in the 1090-1 folder is correct for the 1090-18 also. The -18 had different reel tapes and the reel 2 index disc was different.
you'll have no trouble following the schem - only thing ya really need to know is both the coin relay and handle release relay are electrically tripped and mechanically reset.