Sentinel Supergun - Prototype

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    • Looks good to me, the LM1881 is always the IC that gave me the most grief. Unlike the first one I built you haven't put it on upside down :P

      It might just be the picture but the legs on that CXA facing the controller port look like they might not be soldered down properly. Are you using a good flux to get the solder to flow to the legs properly?

      Running across everything with a hot air him after you've soldered it to straighten it up can help too.
    • It looks okay to me.

      Double check the -5V LED, make sure polarity is correct. There's a + symbol printed on the PCB to indicate the positive pad.

      Before going ahead with anything else, triple check the SMD ICs. You need good light and a magnifier, ensure good contact, enough solder and no bridged pins. You don't want to assemble the rest of the supergun to discover there's a loose joint on the ICs as they'll be difficult to rework with all the other components in place.
    • back from the dead - i mean i woke up again ;)

      Thanks for the advice.
      For the ICs i used a combination of lots of flux, hot air and a soldering iron - i think my hot air gun was set too low because i sa the the solder paste dry but it didn't melt properly ( or i simply wasn't patient enough...) but when i used the soldering iron directly afterwards it melted right away. I did a continuity check on the IC's legs and it looks like there are no bridges.
      The LED i think i soldered in correctly - at least i was aware that it needs to be in a certain direction ;)

      So far it's a great learning experience - i really hope it all works in the end :huh:
    • Thanks Frank!

      My best advice is to just take your time and have fun with it :)

      It looks like you're doing a pretty good job so far and the connections look solid. Once you've completed all the small components it's pretty much smooth sailing from there.

      If you've never soldered a JAMMA edge before, the best way to do it is to pinch the solder tabs closer together to approximately the width of the pcb, as this makes it way easier to solder. I then usually make sure the edge connector is dead straight from side on and tack down the first and last JAMMA pins on either side.

      Another tip is to make sure all of the large through hole components are sitting completely flush with the PCB. Push the component tightly against the PCB and tack down a couple of points to make sure it stays flush.
    • thanks again, my biggest fear was the THS, the last time i tried one i had too much solder paste, but this time it seems to be ok...

      Thank god i asked, because i just realized that i put the led in the wrong way around (the cathode is the negative pad, but in chemistry the cation is the one with a positive charge X/ )

      The post was edited 1 time, last by MoppelTheWhale ().

    • On the underside of the LED is a green stripe and dot. The dot represents the cathode, which means negative.

      One thing I do, use a 9V battery or similar and apply power to the jamma pins to see if the LED illuminates, thus verifying correct polarity and soldering. Remember, this LED measures -5V so apply positive power to any jamma ground pin and negative power to the negative 5V jamma pin, pin 5.
    • It lives! :D

      i had to dial down the colours, they were far too bright in the setting the pots were coming, and all input are working. I'm immensely proud that all worked on first try. Thank you guys for your help!

      On little thing i realized with the megadrive adapters - for me they are the wrong way round when using for example sf2:
      normally i would have:
      123
      456

      withthe adapter i have on the md pad:
      456
      123

      Would that be possible to reprogram? (i'm itching to try out my top3000 :D )

      here's the working setup:



    • Congrats, well done and thank you!

      I arranged the MD adapters in that way as for every other game it makes more sense to have MD buttons ABC as buttons 123. It also makes it compatible with 3 button controllers.

      Personally I don't have any trouble adjusting to SF with kicks on top and punches on bottom row.

      I will see what I can do in order to swap the top and bottom rows for SF usage. Either a physical switch on the adapter PCB or better yet I'll see if I can accomplish it digitally in the microcontroller, and use a button combo to switch between standard and SF layout.
    • In that setup the audio switch of the supergun should be set to mono.

      If you want to utilise stereo audio from CPS2, please use an RCA to 3.5mm cable - run the RCA end to the CPS2 RCA outputs, the 3.5mm end to the supergun. Set the audio switch to off. This will disable the mono jamma audio and feed the stereo output from the CPS2 to the MD2 DIN connector and over the scart cable.
    • Frank_fjs wrote:

      P.s. that CPS2 case looks amazing!
      @hursit for the win :thumbup:

      Frank_fjs wrote:

      In that setup the audio switch of the supergun should be set to mono.

      If you want to utilise stereo audio from CPS2, please use an RCA to 3.5mm cable - run the RCA end to the CPS2 RCA outputs, the 3.5mm end to the supergun. Set the audio switch to off. This will disable the mono jamma audio and feed the stereo output from the CPS2 to the MD2 DIN connector and over the scart cable.
      i just jumed away from work when the md2cable came - but you are right - good eyes :D

      Frank_fjs wrote:

      I will see what I can do in order to swap the top and bottom rows for SF usage. Either a physical switch on the adapter PCB or better yet I'll see if I can accomplish it digitally in the microcontroller, and use a button combo to switch between standard and SF layout.
      In my eyes that would be amazing and improve the adapter even more.