My Supergun prototypes

Yeah, that's right. And even isolating it from ground, the pins are easy to be touched, so I'm looking for protective plastic covers.

Thanks for the suggestion for the DB15 connector, I suppose that removing that protruding screws will improve compatibility with controller accesories.

I forgot to answer this. The only boards that use SPK+ and SPK- to output amplified stereo sound through the JAMMA edge I know about are multislot MVS and they already output line level audio. Adding line level stereo would complicate the design considerably.

This boards outputs sound through left and right channels but mono, not stereo.

Anyway there is a 4 pin connector very similar on how the konami boards are wired: SPK+, GND, GND, SPK-. It's labeled as MVS Stereo at the right of "Speaker out" in the photo.

New prototype, version 1.5.4'.

All connectors and buttons have been made lateral, in a similar way than HAS, with the idea of using top and bottom plexi covers for protection and comfort.

The most innovative feature in this revision is the possibility to fine tune the brightness via one knob to achieve perfect color balance, apart from being able to correct each color and sync through individual pots. I've also added an Audio Gain Volume potentiometer to be able to increase audio level a bit.

There are three modes for sync:

1. (B)uffered by the THS7374 75 ohm impedance matched and AC coupled. Adjustable by a potentiometer for maximum flexibility, there's also the footprint for a test point to measure the output voltage more easily.
   
2. (E)xternal. Processed by an external circuit pluggable in the 2x5 aux connector
   
3. (R)aw. Unprocessed csync coming directly from the pcb, that makes it possible to process it outside the supergun.
   

Now there is support to enable/disable button 5 as suggested by plasia, although button 6 is only supported through kick harness because it would sacrifice a pair of grounding pins.

THS7374's LPF is disabled by default; you can enable it putting a 2.54mm jumper at JP5.

Joystick ports will be DA15-PL-24 as suggested by Frank_fjs.

Footprint U8 is unpopulated to avoid errors connecting speakers in the wrong way and left for experts. There are +5V and GND points at J6.

New version with new name and plexi covers! its design is heavily inspired in the HAS but the circuitry is different. This one is pretty polished but still not finished.

Photos are updated in the first post.