Cams Not Indexing (Stopping)

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Case Study Summary
Game High Flyer
Games Applicable To all
Source robert medl
Problem Reported search wipers not locking in index/home position
Fix confirmed


I have a 1977 Bally High Flyer which is a six-card machine.

There are 3 search units in this game -- one each for cards 1/2, cards 3/4, and cards 5/6. -- The search unit for cards 1/2 is on the control unit in the cabinet back. -- The search units for cards 3/4 and cards 5/6 are on both on a dedicated motor at the top of the back door. The search unit for cards 3/4 is nearest the motor; the search disc for cards 5/6 is farthest from the motor. I am pointing to the search unit for cards 3/4 in this photo:

The way it should operate is that after shooting 4 or 5 balls, the player presses the C button on the footrail to search for winners. The 3 search units should then each cycle in series looking for winners on each card in succession, stop when a winner is found allowing the player to either play for double using the D footrail button or collect a regular win using the R button, pay off the win (paying either 0, a regular win, or double the win), and then move on to finding a winner on the next card.

After the search unit for card 1/2 completes a cycle, it should lock into its index position, and start the search unit cycling for cards 3/4 as it looks for winners, etc.

Similarly, when the search unit for card 3/4 completes a cycle, it should lock into its index position, and start the search unit cycling for cards 5/6 as it looks for winners, etc. In this manner, all cards are search for winners and any winners are paid according to the player's choices of taking a regular win or trying for double or nothing.

My issue is that search disc for cards 3/4 will not lock into its index position. It skips right past as the coil armature attempts to engage the disc. In fact, I noted the coil bracket was bent when I got into disassembling the unit. -- I have completely disassembled, cleaned, lubed all the search discs and associated clutch washers, etc. -- I have made several adjustments to the coil position on the cards 3/4 search unit using the screws on the bottom of the coil bracket in an attempt to get the coil armature to better align with its associated notch in the bakelite disc. -- I replaced the coil bracket for the coil associated with the card 3/4 search unit. -- I believe that the notch on the bakelite disc on search unit for cards 3/4 has become deformed from all of the torque that is placed on that unit, and from general use.

Here is a photo of the search disc for cards 5/6. The coil armature is in the notch, so it is a little tough to see. But the notch is angular and narrow.

Here is a photo of the search disc for cards 3/4. Note the notch is rounded and wide.


Golden Gate section scoring schem. Lido is almost the same.

Since in-line scoring works, the search index unit is positioned ok, the search relay switches are functional, and the slip ring feeds connecting the search wiper hub to the game are in the right grooves.

Generally, either all the sections work, or none do. When only one/some sections don't pay, usually the problem is just dirty contacts on the search disc.

When none of the sections work, it's usually an issue with the "changeover" switches. These switches are operated by a cam attached to the search wiper locking ratchet. When the search wipers spin around far enough, the cam flops the changeover switches to disconnect the inline circuits and connect the section circuits.

On Lido and Golden Gate, that cam is #15. When these switches flop over to connect the pink-highlighed circuit, that should give you a connection through the rightmost circuit branch when a switch in one of the search relays 1-4 is closed, and should power the search index coil to stop the wipers.


If you are trying to figure out how the circuit works, and you're puzzled by the sequence unit reset plunger switch that is shown as normally open, would it help if you knew that switch is normally closed? This is one of the schematic errors. Some screen game schems got it right, some are wrong. The switch is always NC (it opens when the plunger sucks in to reset the sequence unit)

Inspection Debug Procedure

You pretty much check CU switch 15A and 15B and the search disc wipers and rivets, the sequence unit "close at zero" switch (on the side of the sequence unit operated by a pin sticking out the ratchet/gear), and verify the sequence unit is resetting so the close-at-zero switch is, umm, closed.

There's also a quick-n-dirty check. When the search wipers are locked, cam 15 switches are usually still in the section-scoring state. You can just manually close one of the search relays 1-4 and the search index unit will power (assuming the before 4th trip relay is tripped). Just be prepared that the sequence unit will also start stepping up if the motors are running, so don't jump backwards and land on the dog.

Voltmeter Debug Procedure

The quick-n-dirty test works because power is in this circuit when the search wipers are locked. Pretty handy for voltmeter work, but probing depends on if you want to hold/jumper a search relay switch closed.

If you want to skip messing with the search relays, then put one meter probe on wire #18 (start of the pink bit at the top), and poke around in the pink circuit below the search relays. You should see 50V everywhere.

If you want to hold/jumper a search relay, then put one meter probe on fat orange wire #70 on any convenient 50V coil and probe anywhere in the pink circuit to see where the 50V got lost.


Jeffrey writes:

Of course I checked switches 15A and 15B and they were good, holding voltage properly in either mode, in-line or color section. I found my problem on "Big Yellow" and "Little Green" to be the two outside wipers and rivet rings on the search wipers/disc. I had to clean these really well and re-solder the wire connections.

But "Big Red" still wouldn't test all the way through. If it did start to pay only a portion of the credits would be awarded then the whole circuit would drop out.

The cause was a slight "wobble" on the control shaft effecting the position of cam 15. 'BUT' only when cam 15 was in the position where the rotating search disc wiper was testing "Big Red". The voltage never fluctuated on any other color sections. A simple adjustment on Sw 15A and the problem was cleared.

The first thing I tell any person trying to make their game score properly, "clean and adjust switches 15A and 15B". Still, I get caught with a problem on 15A even after I was sure it was good!

Besides the dirty wipers/rivets, , switch 15A simply wasn't making a good was barely closing. Switches should always "overtravel" a little after the contacts touch. This causes the contact faces to wipe across each other, scrubbing them clean and insuring a good mechanical connection.