Wiring 1 happ button to 2 keystrokes.

[whitiex]

i'm going to use 1 button for upper flipper/magnasave.  can i just have 2 NC wires going to the 2 different ipac inputs with only 1 ground?

[PL1]

Yes, but only if you have separate inputs for the overlapping MAME/VP keystrokes. i.e. P1B1 (L-Ctrl) on a separate input from Left MagnaSave (L-Ctrl).

Normally, I recommend wiring it like the diagram below to use fewer inputs.



If you're using 2-terminal buttons for MAME (Goldleaf, Seimitsu, Sanwa, leaf switches, etc.) you can ue diodes like this to isolate the MAME switches from each other while allowing Upper Flipper/MagnaSave to apply ground to both inputs.




Scott

EDIT: Updated picture to show two switches for Upper Flipper/MagnaSave wiring.

[whitiex]

so wire the mame buttons backwards using the gnd as positive NO as gnd?  is the pinball NC connected to anything?

how about wiring 2 buttons in 1 input for the flippers?

thanks for your help

[PL1]

so wire the mame buttons backwards using the gnd as positive NO as gnd?  is the pinball NC connected to anything?

For some reason, people have it in their heads that the Common (COM) tab is always and only ground. (I still need to edit a few pages of the wiki that contain this myth.)

From an electrical standpoint, that is the same as saying that a piece of wire has a positive and negative end -- total BS.   

Most arcade wiring does use the COM tab to connect the ground wire, which ensures that the NC terminal will only have ground on it in case a loose wire happens to come in contact with it, but it's not the only way to connect things.

how about wiring 2 buttons in 1 input for the flippers?

The NC from both MAME buttons goes to the pinball button input using a Y-connector like this.



With the "backward" wiring, when you to press one MAME button, the COM  lever is moved from NC (connected to flipper) to NO (ground) which keeps you from grounding both MAME buttons at the same time -- same trick that's used for KADE Extended Mode.

When you press "Up", only the up input is connected to ground.

When you press "Down", only the down input is connected to ground.

When you press "P1 U+D", both the up and down inputs are connected to ground.

Wire the MAME buttons like "Up" and "Down", and the Upper Flipper/Magnasave like "P1 U+D"




Scott

[PL1]

Updated pic for greater clarity.

I shoulda' knowed something was missing -- thanks for asking.   


Scott

[whitiex]

Thanks a lot PL1. Having the 2nd half of the picture makes sense now. Lol. Thanks for your help. I do know a lot about this stuff.  Just want to make sure before I close it up.   Is 22g wire ok to rewire a CRT TV to a separate switch?  Monetary ok?

[PL1]

22 AWG is fine and, like mgb posted here in your other thread, a momentary switch is what you want since your TV doesn't have a physical latching switch.


Scott