Techno Stuff
How They Work - Score extra step relay
I'm sure you're sitting there saying "yeah, so now we have pulses, but there's still that score extra step relay switch that needs to be closed. What about that, eh?".
This is the reason I topped off the scotch glass while you where clicking the link to get here. This circuit is similar to the replay cams index circuit in that there is an index switch that needs to be closed even though power has been removed from the index coil.
surf club |
| score extra step index switch |
|---|
This switch needs to be open when the index arm is grabbing the small tooth cam, and closed when the index arm is sitting on one of the other cam lobes.
Unrelated to anything, note the slip ring wipers just to the
right of the index switch. They
reach down to the hub on the cam assembly. Those guys
connect the pulse generator switch to the rest of the machine.
surf club |
| relay circuit |
|---|
We have two circuit paths to close the score extra step relay and allow the pulses can reach the step-up coil,
In the purple path, we need the score extra step relay itself to already be closed, so the blue path needs to close it first.
The switch in the blue path is labelled "su arm". This switch is mounted on the score unit so that it closes when the step up coil plunger pulls in. In games with multiple score units, each unit needs to have one of these switches.
The net effect is that the score extra step relay cannot close unless the score unit steps up once to begin with. Now we see why it's called "extra step". If the normal score step-up happens, and the score extra step index arm stopped on the other cam, then the extra step index switch is closed and score extra step relay will keep itself closed.
On surf club, the only way to get the score extra step relay to open again is to cycle the machine and have the index arm drop down to the small tooth cam. This is kinda a bug, so on later games Bally added the square pin switch in the purple circuit. When the square pin hits the index arm, the switch opens and power is removed from the score extra step relay.
On early games, the score extra step relay could sit there powered forever,
and it had a tendancy to overheat after many hours.
overview | pulse generator | score extra step relay | summary
