Lot of stuff has found its way between my and this Mars Trek project, but today I found again time and energy to work on it with RIK.
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Lot of stuff has found its way between my and this Mars Trek project, but today I found again time and energy to work on it with RIK. As a quick recap, this is a game that has sat in a warehouse for around 20-25 years before being discovered. As usual for these kinds of finds, every mechanical thing in its electro-mechanical logic was seized and its logic units have been taken apart, cleaned, greased and put back together. Most of what's left is adjustment issues or dealing with the screw-ups and n00bness that happens with a non-EM guy tries his best with an EM game.
One weird thing was that it started a game but did not give a ball. This led us on an adventure of how an EM game uses its rather confusingly named score motor during the initialisation sequence. The score motor is actually more of a pulse generator than just a directly scoring related thing. This specific issue happened because one of the many switches in it was not making good enough contact. After filing it again, now with more feeling the game started to kick the ball onto the plunger lane.
An hour of debugging and literal 20 seconds of repair. It figures.
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Lot of stuff has found its way between my and this Mars Trek project, but today I found again time and energy to work on it with RIK. As a quick recap, this is a game that has sat in a warehouse for around 20-25 years before being discovered. As usual for these kinds of finds, every mechanical thing in its electro-mechanical logic was seized and its logic units have been taken apart, cleaned, greased and put back together. Most of what's left is adjustment issues or dealing with the screw-ups and n00bness that happens with a non-EM guy tries his best with an EM game.
One weird thing was that it started a game but did not give a ball. This led us on an adventure of how an EM game uses its rather confusingly named score motor during the initialisation sequence. The score motor is actually more of a pulse generator than just a directly scoring related thing. This specific issue happened because one of the many switches in it was not making good enough contact. After filing it again, now with more feeling the game started to kick the ball onto the plunger lane.
An hour of debugging and literal 20 seconds of repair. It figures.
The EM logic is just amazing when it comes to doing a lot of things with very limited hardware. What actually causes the machine to dispense a new ball onto the plunger lane?
Looking at the schematics page that has the ball release coil, it has 2 conditions: out hole relay must pull and switch 4B in the score motor must be active. The score motor runs during the gameplay, but as long as the out hole relay isn't pulling, the path will never be complete for the ball release solenoid to fire.
Once you lose the ball and it's sitting on the out hole switch, the circuit finally completes as the score motor rotates as part of the end-of-the-ball tasks and then new ball is released.
But naturally it's not THAT simple. The out hole switch isn't directly running the similarly named relay. The more I drill into the schematics, the more incredible this thing becomes. As someone who can write code, all this jungle of wires would easily fit into a Nano Arduino which would happily run a software-reimplementation of the whole thing.
Anyway, this game is slowly running out of things to fix, which means we can take the playfield topside apart and clean it up!
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R relay@relay.infosec.exchange shared this topic
