WMS 3 reel issue with #3 reel

[Pior]

I have Williams Model 40s5 Big Bang Piggy Bankin dotmation slot machine it works perfectly but reel number 3 does not alway spin fast two third of the time it spins slow and at times will even stop. If you open the door and close it spins again.  It could spin Fast two or three times in a row then show like 4 or 6 times it is just all random. I swapped reel 3 with reel 1 the reel 3 in reel 1 place spins fast all the time and now reel 1 in the place of reel 3 it randomly fast and slow and also at time stops.  I cleaned all with wire connections as well as the CPU and I/O boards and no change..
Any next step recommendations