Bally Corvette engine theory of operation

[Spandangler]

Hey folks
Any of you clever people out there understand the theory of operation of the corvette engine mech.

I have had mine stripped down (machine bought as a project and never switched on) and compared next to a known working machine.
Forgive my glossary of terms here. I’ll try and describe as best I can!!

I noticed there is a tiny pcb mounted in the centre of the mech behind the Hall effect boards?? If that’s what you call them
Above that is metal horseshoe bracket which seems to have a magnetic coating on it. I’ve taken pics as best I can and circled the part I mean




So I guess my main question is, is that magnetic coating important. What does it do?

My corvette engine mech seems to be missing the magnetic coating





This mech seems like it was developed by NASA

Any info appreciated

Cheers
Gaz

 

[Jay Walker]

I wouldn't claim to be expert about this, but as I understand it the Hall-effect uses the principle that since electricity and magnetism can produce movement, movement and magnetism can produce an electrical signal. In this case, the signal is used to centre the 'engine' cage, with the trimmer pot on the circuit board providing fine adjustment. If you've not seen the machine working, the engine moves to either side after the Cpu has booted up, to check the opto switches, then moves to its centre position, with the additional engine control pcb under the playfield running the left/right solenoids to hold it in place.

I don't suppose this project has the 'engine locking' bracket with it, does it?. Even the one I unpacked had no description of what a bright metal bracket among the spares provided was for. But I thought it showed how hopeful WMS were about reliability. Later on, I refurbished one, which would ram the engine to one side and keep it there, so the owner had used an old fruit machine pay-out spring (the type with brass tags at each end) to try pulling it back to centre. That one had one of the three wires broken off the sensor; still, I can claim that I've taken the engine out of a Corvette.

 

[Spandangler]

I knew I could rely on you Jay

So the fact that my has no magnets on it, mean it won’t function correctly ?

And regards the locking mechanism.. no not that I’m aware of. Wouldn’t know happen to know what it looks like would you?

 

[Jay Walker]

I suspect that it won't, Gaz. Sorry.

The locking bracket is a well-made metal item, somewhat similar to a ball gate bracket. But without any holes for a gate flap, as I recall. It would fit in place on one end of the engine*, and attach to a post (or some static point) on either side to fix the engine centrally.

* after looking at the entry on ipdb, I think in place of one of the 'tie-bars' on top, which hold the sides together.

 

[Spandangler]

Yet another thing wrong with this game. I think you can buy the magnets from
PSPA.

 

[Spandangler]

@Jay Walker do you think the magnets used are of a certain strength bespoke to the game. Or would any small magnet suffice. I have some tiny round magnets I bought for a little extra traction on my scalextric cars .

 

[Jay Walker]

I'm afraid I don't really have much idea whether the sensor is matched to the intended magnetic attachments, or if it may work with an improvised replacement. Provided it's the same amount on each side, it may be worthwhile to try adding some of those magnets.