Guns of the Super variety

[Vertigo]

Afternoon, chaps/ladies,

I'll keep it relatively brief, a novelty for me.

Question 1) Which Jamma pin does the NeoGeo MVS hardware use for game select? Does it make use of the Service button (pin R) for this, or something else? See also: in the test menu of System11 boards, to my recollection there's a Select button there too. What pin does that live on and what's it used for?

Question 2) When I was building my SuperGun, I was advised to add a switch that I think goes (memory is hazy here) "between +5v and -5v for sound so that older games will output audio", or so I remember it, this is probably bollocks though and I'm opening it up later to see exactly what it does connect to. Any ideas on this, whether I really need it, as I've not seen it on any other SuperGun and won't be trying to use anything non-Jamma and can't afford anything really old anyway.

Cheers.

[Vertigo]

Also need to know something more general.
I'm trying to measure the voltages that I'm getting from each pin on the Super Gun's SCART lead, but with it on and running a game but disconnected from the TV, I'm getting a zero reading on every pin.
I'm touching the earth point of the multimeter to the outer shield (pin 21) and assume this is the right place to touch it, and then the reading point to each pin but get nothing.
Any hints for measuring SCART pin voltages?

[NFG]

1. Pin 26.  Google is your friend.
2. Forget this madness.

You don't need to know SCART voltages, you only need to know which ones are GND and which have voltage for your TV's auto-switching.  The rest are variable - you won't find stable voltages on the RGB, Sync or audio lines.  As for the GND and volts, check the SCART pinout on gamesx.com/hwb.

Also, you look sexy in that outfit.

[Vertigo]

Yeh, I know the voltages are variable, but I'm getting nothing on any pin, even though it's on.
Anyway, this sound switch appears to be connected to the Speaker - and Speaker + lines on the JAMMA, and middle pole to earth. So it has a choice to power either pin L or pin 10.
My Supergun doesn't have an internal speaker, it outputs sound via a SCART lead.
If this switch is of no real use to me, I'd like to re-wire this switch to be a test mode switch instead, or replace it with a 3-way and have Test and Service on it, which would save drilling a new hole and would result in less faffing with wires as I could just de-solder from pin L and solder to pin 15.

In essence; do I really need pins L and 10 wired up?

And you're looking suitably hawt too honey