Puzzling button issue with SNES-DB15 adapter and supergun

massimiliano

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Hi everyone,

I just received a pair SNES-to-DB15 adapter from Arcadeforge, one of those things that allows you to use a SNES pad on a DB-15 supergun/neogeo.

http://arcadeforge.net/Supergun-MAK...-Gamecontroller-Adapter::133.html?language=en

snes_strike_05.jpg


I'm using it with a MAK strike supergun, from same seller, which so far has been rock solid and works flawlessly with a DB-15 neogeo cd pad.

now thing is, if I put the SNES adapter on player one port, button C is not registered, BUT, if I put the same adpater on player 2 port, everything works.

As mentioned, 1P port works perfectly with all buttons with a neogeo pad and I even used a wire connected to ground on one end, to test the button C pins from the jamma connector, all the way to the DB-15 connector on the SNES adapter PCB... input is registered correctly this way. :spock:

So, sounds there is something I may have to investigate for which player 1 port is different from player 2 port!? Sounds a problem with the adapter but why only on one port!? Also, both adapters are showing the same issue...I doubt both are faulty.

Of course I contacted the seller, he is available to troubleshoot but communication is somehow slow and he seems puzzled as much as I am.

Any idea?

Thanks!

Massi
 

GohanX

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If you've got a multimeter check the voltage coming off of the 5V pins on each controller port and see if they are different. IIRC some people were having trouble with Toodles converters on Mak Strikes because of voltage spikes.
 

massimiliano

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If you've got a multimeter check the voltage coming off of the 5V pins on each controller port and see if they are different. IIRC some people were having trouble with Toodles converters on Mak Strikes because of voltage spikes.

Gotcha, thanks will check that!

Also, a very strange thing I noted:

with Mak strike main power switch OFF and PSU plugged in: when I insert the SNES adapter (on both DB-15 ports), the power LED turns on but with a very low light, nothing bright like when I turn ON the main switch.

...?
 

GohanX

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I was just looking that up and yeah, that's a design flaw. It was Undamned's decoders, not Toodles, but the Strikes were frying his converters. Basically, the controller ports are getting 5V all the time, even with the power switch off. When you flip the switch on the port is getting a massive spike up to 15v, which either caused the converter to freak out or fry completely. I would assume the creators of Mak Strike know this, and would have designed their converters to compensate, but who knows. The fix for this might be to simply wait until the gun is already powered on before plugging in the adapter.
 

massimiliano

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I was just looking that up and yeah, that's a design flaw. It was Undamned's decoders, not Toodles, but the Strikes were frying his converters. Basically, the controller ports are getting 5V all the time, even with the power switch off. When you flip the switch on the port is getting a massive spike up to 15v, which either caused the converter to freak out or fry completely. I would assume the creators of Mak Strike know this, and would have designed their converters to compensate, but who knows. The fix for this might be to simply wait until the gun is already powered on before plugging in the adapter.

I see... very interesting.. also, I think my rev. may be the second one and there could be a third one around.

...I don't understand the spike though...wouldn't it require a cap? (btw, I'm not feeding +12 at all, as I'm using the line stereo source from the mvs board).

wouldn't the spike fry the mvs board too?

if it is just a controller port issue, shall I cut +5 trace and take it from somewhere else?
 

GohanX

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The spike was only on the controller pin, since it seemed to tap it from unswitched power. It wouldn't affect boards. But yeah, I think that's what Undamned did on the Strike he was testing, cut the trace and get the 5v from a switched source.
 

massimiliano

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The spike was only on the controller pin, since it seemed to tap it from unswitched power. It wouldn't affect boards. But yeah, I think that's what Undamned did on the Strike he was testing, cut the trace and get the 5v from a switched source.

gotcha, thanks a lot!

may I ask you a link for reference? so I can prove the issue in case of refund.
 

massimiliano

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thanks!

btw, just tried to power on the supergun first, then plug the adapter...no change at all.

Actually I tried both adapters and it is even worst:

adpater_1--->P1 port = button C is not working
adapter_1--->P2 port = all buttons working
adapter_2--->P1 port = button C is not working
adapter_2--->P2 port = nothing works!

I even waited few seconds to allow the small cap on the adapter PCB to discharge....WTF!?

anyway, it seems not related to the spike but rather teh adpaters are very sensitive to +5!? (or +5 pins on db-15 ports of the MAK strike are feeding polluted current!?) ...that woudl explain some erratic behavior...

Btw, I used two different PSUs, both with enough Amperes, one is an arcade new PSU fine-adjusted to output steady 5.0v (confirmed by the onboard voltmeter)

Edit:
screw it, I'm gonna cut the +5 trace from the DB-15 port and wire it directly to the main line..
 
Last edited:

massimiliano

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Small update, I used the adapters on a MVH-1 with embedded joystick ports, they work flawlessly.

It is definitively an issue with the MAK controller port +5v...

Edit:

cut the trace, jumped straigth to the main feed (PSU +5) ...no luck... WTF?

Is it possible that the whole +5v is kinda polluted by the MAK?

My only option left is to feed the +5 from a completely separated circuit to confirm the issue..
 
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aha2940

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Small update, I used the adapters on a MVH-1 with embedded joystick ports, they work flawlessly.

It is definitively an issue with the MAK controller port +5v...

Edit:

cut the trace, jumped straigth to the main feed (PSU +5) ...no luck... WTF?

Is it possible that the whole +5v is kinda polluted by the MAK?

My only option left is to feed the +5 from a completely separated circuit to confirm the issue..

Have you considered that the problem may be the pin on port 1 that registers button C? it may have trouble making contact with the adapters for whatever reason...
 

massimiliano

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Have you considered that the problem may be the pin on port 1 that registers button C? it may have trouble making contact with the adapters for whatever reason...

I'm 99% sure it is not... I verified continuity from the JAMMA pin 24 up to the DB-15 male pin on the SNES adapter PCB...I did move the connector as well, that's not the issue.

Fun test I did:

After cutting the trace from pin 8, I soldered a loose wire to it, so I could use the other end to plug +5v feed from different spots on the MAK strike... well, basically, if I plug the wire back to +5v connector and then *remove* it, the controller works perfectly (not sure for how long)
So, sounds like if I'm charging the small capacitors in the adapter PCB, the residuate current will allow the adapter to work normally...

If I put the wire back to the main feed, the controller stops working.. I'm quite positive the +5v feed of the MAK strike is polluted (enough to mess the adapter...maybe it is too sensitive?)
 

massimiliano

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It is definitively the MAk Strike... sounds like the 2010 ver, may be incompatible with this adapter... I've been offered a discount for the 2015 model, sounds fair enough.

I'm still tempted to try to pick a "clean" +5v somewhere in the MV-1C hopefully after some caps that will stabilize things and route it to pin 8,? ..any advice?

Thanks!

Massi
 
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