Advice and guidance on repair and restoration techniques.
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Adjusting worn bandit "dog & cog" so cycle completes

Postby coppinpr » Sun Jun 30, 2013 11:53 am

For the benefit of newbees:

Sometimes when I repair machines it occurs to me that someone new to the hobby might gain from what I'm doing at the time, so with that in mind and the fact that my memory is so bad I'll have to look it up myself in the future, I thought I'd write short articles that might help.
So far I've added articles about refitting reel strips and aligning reels and payout discs to the forum.
This week I've been working on a Jennings that was badly worn and not paying out at all.
This is what I found and how I corrected it - simple, but if you don’t know what to look for, it can be frustrating.

Problems with the “dog & cog”
Not the correct name but one often used on this forum to describe the connection between the arm being pulled and the mech completing a cycle. (see photo 1, connected). and photo 2 (not connected)

Note:- the photos are of a Mills mech which is much the same as the Jennings
This consists of two parts which only engage when the machine has detected a coin in place (on a mechanical mech this is achieved by a pin type coin detector causing the flexing part (a) to engage the fixed part (b) when the handle is pulled, on an eletro-mechanical mech this is usually achieved by a solenoid holding (a) in place when a coin is detected.

The fixed part (b) is almost always held in place by a serious bolt that will be seriously tight. Once the bolt is released, part (b) can be easily adjusted, but should be done so VERY carefully and in very small amounts and only after all else has failed as it controls many of the timing sequences on the mech.

After removing the reel bundle from the Jennings, I could see that the failure to pay was due to the clock operated slide brake that holds the slides back while the mech checks for a winning combination not being able to engage because the slides were not moving forward far enough. There are several reasons why this might occur ,the push rod that moves the slides could be bent or worn for a start, I checked all around before deciding that it was the dog & cog in this particular case.
The parts had simply become worn on the ends and were not connecting long enough to lift the main bar far enough to push the slide bar forward to the right place.
First I marked the existing adjustment position of part (b) so that if all hell broke loose I could at least return it to current state of affairs.
Then I loosened the large square headed bolt(C) that holds (b) in place , it was tight but not a problem.
I then tapped (b) from the back moving it forward no more than an eighth of an inch. ALWAYS adjust in this direction in tiny amounts, starting with a big forward adjustment with the intention of moving it back a little at a time can be a disaster as too big a an adjustment can make the whole thing jam solid mid cycle with all the springs at max tension, fingers can be at risk releasing the jam. ( resulting in “jammy fingers” only the red stuff won't be strawberry flavoured)
I re-tightened the bolt and cycled the mech, great! the slide brake moved in correctly and all the payout slides fired as they should with the reel bundle still out of the machine.
Feeling full of fun I replaced the reel bundle and tried again, no good this time, the payouts worked fine but the adjustment had reduced the power of the kicker so the reels barely moved. A perfect example of how a very small adjustment of this part can throw things out.
I loosened the bolt moved the part back a 16th and tried again, perfect this time. I then made double sure the bolt was tight and part (a) was clean and moving easily and it was finished. As I said, a simple adjustment but one fraught with pit falls. Remember, try everything else first!!

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Re: help for newbee's

Postby gameswat » Sun Jun 30, 2013 1:14 pm

I like the cut of your jib CP, nice job! Pity I'm too lazy to follow your lead. Writing down what I do is painful for me to say the least.

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Re: help for newbee's

Postby badpenny » Sun Jun 30, 2013 3:29 pm

Useful stuff there Paul and the advice about trying everything else before resorting to adjusting the Dog or Anvil or whatever it's called is spot on. It's amazing how moving it a millimetre seems to have an amazing effect to critical parts.


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