Williams Palooka.
This is a new problem, and it doesn't affect gameplay, but it is irritating. As stated in the topic, when I start a new game, the tens reel gets stuck on 6. If the reel is on 7, it will reset to 0, but if the reel is on 1-6, nope. It's stops at 6. The 10s reel works fine during game play.
So far I have taken the reel apart and cleaned everything with alcohol. I have also cleaned the contacts.
It works fine when I activate it by hand.

Any ideas are greatly appreciated.

Good question. I'll check.

Now that I've asked for help, the problem isn't constant, it's sporadic... shakes head.. for ten times in a row I was stuck resetting to only 6, and now the tens reel is resetting to zero every so often.

I'd like to think the machine will "play through" this problem, but I'd like to know what is causing it to stick at 6.

This is an AAB (my only), and a previous owner installed a free play switch in the coin door. You have to hold it in for just the right amount of time for the game to fully reset. It hasn't been a problem before, but I'm wondering how it works?

Does the reel reset always go through a 5 step process?

What should I clean?

Good to know. I'll try to think this out.

The top switch on the 1s reel wasn't making contact. All the reels now reset correctly, and the machine starts better than before.
Thanks for the replies zacaj.