Quoted from pinballdork:Just tested it. With the coil power set to Soft, the gate opens properly. Also checked with the coil power set to high: it looks like the coil opened the gate for a brief second... but it could have been the flashing lights...
Excellent. Thank you for verifying for me.
I'll tell you exactly what the bug is here... this will get a bit technical but some of you might find this interesting.
All the coils have a set value for how long they are to remain energized. When you set Adjustment 32 (Coil Pulse Power) to Low then the amount of time is decreased by a small amount. When you set it to High, the amount of time is increased by a small amount.
All the coils have a different base value for time. To keep this simple, I will give all numbers in decimal.
The upper right coil timing is set to 240 when it is at the default setting. This means that coil will remain energized for 240 units of time.
When you set it to Low, the code subtracts 30 to the timing of this coil. This brings it to 210.
When it is set to High, the code wants to add 30 to the timing of this coil. This brings it to 270. However, the software is running in 8 bit hexadecimal numbers here. The largest number you can represent with 8 bits is 11111111, or 255 in decimal notation. So the number roles over to 0 if you try to go above that (and don't account for it). In this case, it ends up rolling over and winds up being 14.
Setting the coil power to High in this specific instance takes the coil power from 240 to 14. 14 is such a tiny amount. You can see the effect in the game that the gate probably just barely opens and immediately shuts.
Apparently, this was never tested back in the day and this bug slipped out into the production code.
The Upper Right Coil is the only one that has this bug. All the other coils are have a default value that does not roll over when changing power level.