Minigun Supergun - An Open Source Supergun

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    • acblunden2 wrote:

      Frank_fjs wrote:

      Oh, re the gap, you need to manually bend the pins inwards with pliers or a screwdriver.
      Ahh, k. Was that the case with the Sullens edge connector too?
      Yep. Will be the same regardless of connector. It's not ideal but not really a problem, spend a few minutes bending the pins in and it solders nicely. Wide pins, high current capability, strong physical connection and it lines up perfectly with the centre of the PCB edge.

      There are through hole edge connectors but I'm not sure I like them. They're more expensive and more difficult to source.
    • More updated PCBs landed today. I'm not happy with the voltmeter placement. It works but is rather close to the jamma pads and it's a squeeze regarding mounting hardware and the left hand audio cap.

      I think it may fit better and not get in the way of anything just below the P1 DB15, so I'll try to implement it that way. If not I may have to remove it from the PCB, it's just too tight a fit being such a compact PCB. Worse case scenario people can still mount a voltmeter by attaching it to the jamma connector, with some foam adhesive tape etc. I don't think it's a mandatory feature, should really be checking voltages with a proper multimeter.
    • Ok, cool. Then I have a proper edge connector to get this together this weekend then. Looks like there is enough of a gap as I solder on the PCB so I can slide 22AWG wire between the pins. I’m doing this to get unattenuated video and maybe audio right off the back of the edge connector for test bench purposes (drive an arcade CRT).

      Do you foresee a problem with the THS amp circuitry if I tap JAMMA RGB before it is fed to the amp?

      FYI, I haven’t dry fitted the resistors and caps yet, but the DB15, 3.5mm audio jack, Mini DIN 8, from your Standard version 1.1 BOM fit perfectly. Nice and snug.

      As for voltmeter, I picked one up from your BOM but I don’t think I will use it until a pure test bench fork is designed. These things aren’t super precise and to be quite honest, is just ceremonial. Its inclusion really isn’t anything more than a power indicator LED, which is already there.
    • These connectors are very nice:
      • HRS CR7E-56DA-3.96E
      • KEL 1168-056-009
      Both are great, but Hirose ones seems to be better according to the datasheets and they have a key that blocks the unused pin to avoid connecting them incorrectly. Digikey has no stock, but they are currently available at Mouser and at Smallcab.net. I don't think they include the key at Mouser/Digikey.

      I have not checked if they fit the PCB, but I hope to receive today version 1.1 so I'll post here once I check it.
    • rsignal wrote:

      These connectors are very nice:
      • HRS CR7E-56DA-3.96E
      • KEL 1168-056-009
      Both are great, but Hirose ones seems to be better according to the datasheets and they have a key that blocks the unused pin to avoid connecting them incorrectly. Digikey has no stock, but they are currently available at Mouser and at Smallcab.net. I don't think they include the key at Mouser/Digikey.

      I have not checked if they fit the PCB, but I hope to receive today version 1.1 so I'll post here once I check it.
      Lots of people favor the Hirose one as those were what was included in many Candy cabs (hence the higher cost). But I find that the shorter ends break out easily. I've seen many a Candy cab where the edges are broken off the Hirose edge connectors. TBH, in all my US woodies with Happ harnesses, not a one has had the short edge break off and I can't recall seeing that on any other US woodies.

      The EDAC version seems to be very good. It's going to get a lot of work on my test bench :). Made of stronger composite instead of brittle pure plastic like the Hirose. And there is a polarizing key available, which might work with other edge connectors. Keep you guys posted.

      Don't know about the KEL version or the Sullens version.
    • The LW-S28A2G is quite good. Probably has the best quality to price ratio. Not as readily available but they can be found. Gold plated pins, nice plastic and texture, perfect grip.

      I'm not a fan of the Hirose. Very expensive and last I checked it was discontinued. It WILL break on the edges given enough use and time (my Astro has one and I hate it, very easy to have misaligned pins).

      The Sullins connector oozes quality. I have one but have't used it yet as I'm going to save it for the final revision. Aside from the plastic being super high quality, the pins are clearly superior to cheaper alternatives. It has some serious weight to it too.

      I'm going to remove the voltmeter and release what I anticipate will be the final revision, REV-1.5. Everything else is fitting and working as intended now.
    • Frank_fjs wrote:

      More updated PCBs landed today. I'm not happy with the voltmeter placement. It works but is rather close to the jamma pads and it's a squeeze regarding mounting hardware and the left hand audio cap.
      What saved me from such situation, was doing a "dry run" first (even before ordering the prototype PCBs). I print the board layout, cut it, and place the components on it to see if the components placement is right.
    • RGB wrote:

      Frank_fjs wrote:

      More updated PCBs landed today. I'm not happy with the voltmeter placement. It works but is rather close to the jamma pads and it's a squeeze regarding mounting hardware and the left hand audio cap.
      What saved me from such situation, was doing a "dry run" first (even before ordering the prototype PCBs). I print the board layout, cut it, and place the components on it to see if the components placement is right.
      Indeed, a much smarter, more efficient and economical way of doing things!
    • At this point, I think I'll wait for your confirmation that the design is finalized once you receive the 1.5 protos before ordering more boards.

      I am looking at LW-N28A2G connectors on ebay, and there is a seller from Taiwan that has 2 variants of those connectors, one stated as "Heavy mode". Anyone know the difference between both? There is quite a price difference for very similar listings.
    • I built a Minigun 1.1 and made some tests:
      • Konami Punk Shot sounds distorted, anyway this board is really picky with the speakers and only sounds fine with a speaker and distorted with others.
      • Tetris and SF2CE bootlegs have no sound (they work connecting Speaker+ and Speaker- directly).
      I tested the board with a Neogeo MVS and it works fine. Picture is perfect with all boards I tested.
    • I've tried with a Blaupunkt and a Philips old fashioned CRT tv set. I've tested punk shot only at Blaupunkt TV, not with the Philips. I think this distortion is related with the speaker impedance.

      I made a cable wiring from the pcb to a SCART connector (I'm still waiting for the 8 pin mini din male connector).

      For audio I connected Left and Right pins (2 and 6) to the audio signal coming from the attenuation circuit, AGND is connected to ground. I made sure speaker- is not connected.
    • I've made some tests with different boards and power cables soldering them directly to the jamma pins to discard issues with the pcb tracks and the jamma connector. The cables are approximately 10 inches long.

      In my experience the only way to reduce voltage drop consistently to 0.01V is to use two 15AWG wires (1.5mm copper diameter) for +5V and two 15AWG wires for GND. The problem using 18 AWG wires is that big boards like Ninja Gaiden drop the voltage to ~0.1V while smaller boards like MV1B voltage drop is ~0.01-0.02V. This makes difficult keep the voltage at the jamma edge very close to 5.00V for big and small boards without voltage adjustment.

      I wonder if this happens to other people using 2x 18AWG wires for +5V and 2x 18AWG wires for GND. Maybe my 18 AWG cables are shit. I've measured the copper section and the diameter is 1mm. According to AMOA standard there are three cables for +5V and GND, so if they are 18 AWG I'm using the same section (3mm diameter in total)
    • Nice photos, thanks for sharing!

      @ekorz, please do try the advanced. If you do, don't forget to download the latest zip file, better to be using V1.5. I will be receiving the PCBs in that zip file probably end of next week and will report back.

      @acblunden2 I use 2 x 18awg for +5V and GND, no issues on my end. Arcade PSUs aren't regulated, which is why they have an adjustment screw. Part of the nature of running arcade boards, you will need to make adjjstments to power from time to time pending board.