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Frank_fjs

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Minigun Supergun - ADVANCED edition

An Open Source Arcade Supergun

Minigun_3D_R2.5.png

Design goals and considerations:
  • Open sourced
  • Minimalist design
  • Low cost
  • Easy to assemble
  • Safe
FEATURES:
  • 2 layer PCB - 110mm x 50mm | minimum 8mil trace width & clearance | 40 vias.
  • Arcade PSU connection via Molex 6 pin Mini-Fit-Jr connector.
  • COIN & SERVICE tactile switches.
  • 2 x Neo-Geo style DB15 connectors for player 1 & 2 inputs. Follows Undamned pinout.
  • Buttons 12345 on Jamma edge - Buttons 456 via kick harness connector. Buttons 4 & 5 may be toggled from the Jamma edge via a dipswitch.
  • 8 Pin MINI DIN video and audio connector. Follows XRGB MINI / RGB MODDED NES / HAS pinout.
  • 3.5mm audio output connector which disables audio output from the MINI DIN when utilised.
  • Speaker to line level audio conversion - DC blocked - No Jamma audio pin is ever grounded.
  • MONO or STEREO audio output. Selectable via a jumper.
  • THS7374 based video circuit for RGB and SYNC signals. Buffered, attenuated and 75 Ohm impedance matched. Adjustable trimmer pots used to attenuate RGB levels. LPF may be enabled / disabled via a switch. Fixed resistor voltage divider used to attenuate SYNC.
  • Power LED.
  • Voltmeter to monitor +5V.
  • OSSC safe.
The ZIP file(s) below contains the Gerber files for PCB fabrication, the Easy EDA source file for editing, the BOM and schematics:

MINIGUN VERSION 2.5 (FINAL) MINI DIN 8:

View attachment MINIGUN_REV2.5.zip

MINIGUN VERSION 2.5 (FINAL) UPDATED TO A SEGA MEGA DRIVE 2 / GENESIS 2 MINI DIN 9:

View attachment MINIGUN_MDIN9.zip

ACCESSORIES:

SYNC BOOST PCB:
  • Input RGBS via Mini DIN 8.
  • Output RGB-S via a male VGA connector.
  • Outputs TTL level sync.
  • Designed to be used in the AV3 VGA port of the OSSC to allow Taito F3 and other boards with out of spec sync rates to work. Set H-PLL Pre-Coast & H-PLL Post-Coast to 4, under Sync opt.
SYNC_BOOST_V1.2.png


SYNC BOOST PCB REVISION 1.2:

View attachment SYNC_BOOST_REV1.2.zip

4 PLAYER ADAPTER:

FINE PRINT:
  • I encourage people to share any improvements they may make in the spirit of the open source philosophy and to further improve the product.
  • You are free to build, use, sell, distribute as you like. Credit and a link back to here would be appreciated.
  • I offer NO WARRANTY of any kind and assume NO RESPONSIBILITY for any potential damage caused by this device.
  • This entailed a lot of work. Monetary donations, while completely unnecessary and not expected, will graciously be accepted and used to further improve and refine the product, and maybe to treat myself to something nice. :)
  • PayPal: frank.fjs22 AT gmail.com (replace AT with @).
 
Last edited:

RealMFnG

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Let me see if I can whip up a components list at Digikey. Hope all the components can be found from one vendor.
 

Frank_fjs

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Thanks Smoke.

A few clarifications:

Both editions, standard and advanced, are identical in features barring:

Standard: Through-hole components. THS7316 RGB video circuit.

Advanced: Surface mount components. THS7374 RGBS video circuit. Power LED.

The remainder of features and circuitry is identical between them.
 

pacoarcade

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Great! thank you, this is really useful and interesting.

It would be nice to have another way to fund your work since Paypal fees are abusive when donating from EU to outside (around 4€ for 10€ donation).
 

Frank_fjs

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Thank you @rsignal - greatly appreciated.

Could you elaborate re the sync booster?
 

nem

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It would be nice to have another way to fund your work since Paypal fees are abusive when donating from EU to outside (around 4€ for 10€ donation).
For small amounts it's way cheaper to send a normal payment and let the receiver pay the fees. So if you're wanting to send 10 euros, add 5% to it and send 10.50 as a normal payment.
 

Kavas

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This is so cool, thanks!

I am somewhere far down on the HAS wait list, and currently have no way to test any of my arcade hardware. Was actually shopping around last night for other cheap supergun methods. I know tons of people say to stay away from any cheap solutions so I did, but I wished there was something more streamlined and basic out there for those of us just getting started. This looks to be it.

I would attempt to throw one of these together but I have never ordered any PCB to be manufactured before. I think there is a minimum order amount right? I am proficient enough in soldering to handle the rest I think.
 

pacoarcade

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I refer to the Martin Jones Sync Pulse Generator, anyway this defeats the simplicity of the design and since it's only needed for some boards it probably goes better outside the Minigun.

@Kavas I have successfully ordered other boards from oshpark.com (USA) and jlcpcb.com (China). There is also dirtypcbs.com
 
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pacoarcade

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Please could you specify the connector for the PSU that plugs into Molex 35318-0620 (WM13196-ND)?
 
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Frank_fjs

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Check the main post under supplementary parts. Have listed manufacturer and digi-key part numbers for the Molex receptacle, crimp pins and JST crimp pins.
 

invzim

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If you provide schematics, maybe someone can give you technical feedback. I would strongly suggest to have a look at some of these signals with a scope to see if they are within safe spec for both the amps on the board, and what is output from this PCB and especially the actual game PCB itself.

6mil traces are quite thin, for a board like this I would recommend sticking with 10mil minimum.
 

The Spaniard

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Would it not be fairly trivial to add the power led to the standard version?
 

pacoarcade

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Could you recommend a crimping tool for these Molex terminals? the official one costs ~241€ + taxes and that's way too much just for making one or two miniguns.

I've found Engineer crimping tools decently priced but I'm not familiarized with Molex connectors and I'm not sure if they'll work with this. I have an IC extractor and a wire stripper from this brand and they are pretty good.

About the correct levels in video signal I recommend setting the 1K trimpots as 682Ω in series and 318Ω to ground before power on. This divides the 2.2Vpp signal to 0.7Vpp.
 
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West

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You rock @Frank_fjs. Thanks for putting this together. Sets a great example for the community. Sent you a drink or two on me.
 

Raph_friend

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It is possible to provide us the schematic file too, @Frank_fjs?

(I want to check the THS circuit)


Thanks for the great work.
 

SmokeMonster

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Thanks Smoke.

A few clarifications:

Both editions, standard and advanced, are identical in features barring:

Standard: Through-hole components. THS7316 RGB video circuit.

Advanced: Surface mount components. THS7374 RGBS video circuit. Power LED.

The remainder of features and circuitry is identical between them.
Thanks! I've updated the article :D
 
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