I picked up a bunch of control panels today for VO, and am wondering what I need to use these with the Naomi.
nothing special... they're all digital controls. VOOT 5.66 does use outputs for the start button lamps (or the billboard if you enable it) so the Capcom I/O may be problematic, but the Type 1/Type 2 and Sega JVS to JAMMA all work fine.
Left stick and buttons are mapped to player 1 joystick and buttons 1/2, right stick and buttons are mapped to player 2 joystick and buttons 1/2.
What sticks are you using?
Assuming you're using the sticks from the VOOT/Force arcade machines (some of this applies to Saturn/PC/Dreamcast sticks as well) I highly recommend disassembling and re-greasing the ball joint and spring hat (I use Dow Corning Molykote 44 Medium for all my sticks) as well as the trigger.
The #1 failure point on these sticks is the grip cracking/falling apart around the screw holes, There are actually a few revisions of the sticks used in the arcades, the earlier ones have a round shaft with a smooth hole and the grips have a semi-circle cut out around the shaft and are held in place with 1 bolt per hole and a nut that is slotted into the grip on the other side.
later they added square sections to the shaft around the bolt holes, and the final revision the shaft is square the whole length under the grip. Ton these the grips have a square cut out around the shaft and the shaft has threaded holes with philips screws designed to thread in from either side (so 2 screws per hole)
The later revisions hole up WAY better but are still prone to cracking. Check this out and if you can reinforce the plastic around the screw holes/fix any cracks with epoxy and plastic filler (like Q-bond).
The only reason any of these sticks survived is because Japanese players are respectful, nearly every VOOT cab I've seen imported to the USA had OMG sticks retrofitted to it because American players likely destroyed these fragile-ass grips within a month.
I believe the grips on the Dreamcast/Saturn sticks are the same as the early revision arcade machine sticks, or at least similar enough that you can make them work if your grips are too far gone to bolt up to the shaft. (I've never investigated this personally so I can't say for sure). Keep in mind that the colors don't match. Saturn/PC grips are black and Dreamcast grips are light gray, while the arcade machine sticks are dark gray.
Chances are if you got these sticks from Outtrigger or VOOT Candy Panels, or a 5.2 Twin unit then you have the early revision sticks... later revision sticks came from VOOT 5.66 twin units, VO Force, and Gundam Battle Operating Simulator machines. I have found later revision sticks on Outtrigger and VOOT candy panels though so I'd assume these were replaced by the operator at some point when the original broke.
#2 failure point on early revision sticks is the button arm on the back of the trigger, it's thin plastic and it flexes every time you pull the trigger, they eventually snap after enough use. Later revisions got rid of the arm and just has a microswitch behind the trigger, these work well. if you have an early revision you can hack this setup in place by snapping off the arm and just hot-gluing a microswitch where it needs to be, you might have to cut away some of the plastic around where you're mounting the switch... I'd recommend NOT doing this until your trigger arm breaks though since it will just snap itself naturally anyway, no reason to hack up your stick if you don't need to.
#3 failure point is the spring hat. This isn't a problem on the arcade machine sticks as long as it's well greased. but if not then the spring will start eating away at the corner of the hat and eventually crack and break off. This is actually the #1 problem on the Saturn/PC/Dreamcast stick. the Arcade machine sticks have a really beefy nylon spring hat, but the home sticks have a thin ABS spring hat, it's bad enough that there was a company in japan that used to make upgraded replacements. They even still pop up on YAJ every once in a while. I've seen a few hacked solutions for replacements over on oratan.com but I can't comment on how good any of them are.
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If you're using OMG Twin unit sticks... firstly these wont fit in a candy cab panel (which is why the kit/Versus City version of OMG in Japan used different sticks), but just make sure everything is well greased, and I recommend using loctite on the screws for the ball-plate as they have a tendency to back out... these things are built like a tank though... seriously well constructed.
Sanwa 8-way flight sticks seem well built, I don't have any first hand experience. these are also used in the Hori Twin Sticks for Xbox 360 and PS3. the off-the-shelf arcade variant has a really shitty grip design that looks nothing like the official sticks. the Hori units use official Sega grips but the bolt hole spacing and shaft dimensions are incompatible with the official arcade machine sticks... also the hori grips are black while the arcade machine grips are dark gray.
The only other 8-way flight sticks I know of are the really REALLY ugly sticks used on the OMG/Versus City kit in Japan. (I have no experience with these but I've heard they're shit) and the generic no-name sticks that look like a really chunky bat top fight-stick with a trigger. Again no experience with these.