I don't believe that they can be adjusted. Just the math behind hitting a jackpot with three reels and all the combinations should make you not want to put your money into it. But it's that chance of winning that compels us to throw our paychecks in there.
I have seen where a machine would have a small nut and bolt in the cog to stop a jackpot. The machine would let you get two of the three jackpots symbols, but as the last one gets ready to lock into place, the other geared piece would ride over the bolt and skip over the last needed jackpot position. Darn the luck, it just skipped right past that winner.
I wanted a slot either a Watling or a Mills. The Watlings are cooler looking. The Mills are more affordable. I settled for an Evans Winterbook, and Acme Roulette machine, and a Mills Vest pocket. The Vest Pocket doesn't even look like a slot machine. It is a stealth slot, made to resemble a vending machine. One day, I would like a full sized machine.
