Switching power - Naomi Mobo and Namco Jamma>JVS (Relays?)

[FrancoB]

Maybe a bit of a strange info request this one.

In my Net City I have a N1 mobo and a Namco Jamma>JVS adapter. I'm planning on splicing the six and eight pin plugs that connect to the mobo and running another set so that I can have the Jamma>JVS adapter plugged in at the same time. I want to do this as the plugs can be quite stiff and I dont want to keep cycling the connections and risk damaging anything, plus its a PITA.

I would, however, like to be able to control them so that they are not both switched on at the same time. I have read that the Naomi mobo uses +3.3, +5 and +12v, I presume that the Jamma adapter will use +5v and 12v.

Would it be feasable to wire up a switch to control one of the power lines which would in turn power them on/off?

Would that work or would it be a bad idea as both boards would be getting power from the other power line that isn't switched?

Maybe the grounds for each board could be tied together and switched, assuming of course that all the grounds are common.

Any other bright ideas that would work?

Thank you please

[FrancoB]

Okay, so after speaking to invzim last night he suggest switching both the 5v and 12v between the two systems.

If I was just switching either 5v or 12v then I could use a SPDT switch, correct?



So in that case I could use two SPDT swiches, one for the 5v and one for the 12v, correct?



But I have been reading a little and apparentely a DPDT switch is like two SPDT switches with the levers tied together so would one of these simultaneously switch the 5v and 12v between the two devices?



Yes, you are correct, my paint skillz are :awe:some, thankyou very much!

[dj_johnnyg]

You are correct in that a DPDT will do the job.

Is there no risk in keeping the 3V flowing to the Naomi Mobo?

[FrancoB]

Thanks Johnny.

ReplicaX has been helping me with the problem a little in chat and he found a suitable DPDT for me.

I have no idea if the 3.3v needs cutting, electronics isn't really my strong point

I suppose a TPTT would work if they existed but a quick google seems to show that they don't.

I could use a DTDT for the 12/5v and a SPST for the 3.3v (or a SPDT if the Jamma>JVS needs 3.3v too).

Is there anything I could use for an 'all in one' solution? Maybe something for with relay(s) or something?

Whatever I use has to be rated at 20A at 12v as thats the peak output of the PSU.

[FrancoB]

Okay, I have been reading up a little on relays a little [here] and I'm thinking that this may work?



Any thoughts?

[ReplicaX]

Yes, that would work with 12v relays as well. Better off going with a switch.

[ReplicaX]

I suppose a TPTT would work if they existed but a quick google seems to show that they don't.

You want a 3PDT to accomplish all 3 voltages to 2 outputs. They are easy to find as well, search "3PDT On - Off - On".

[FrancoB]

Thanks for the help again ReplicaX

Ah, I was searching for the wrong type of switch, thanks.

If that relay setup will work then I think I will go down that route for a couple of reasons.

a) The switch to control the power is going inside the CP and the relay setup will mean I only have to route two wires from the rear of the base to the SPST switch rather than nine to a 3PDT.

b) I should be able to find a nicer looking SPDT switch than a 3PDT one as aesthetics are important too.

c) I should be able to 'aquire' some 12v relays from work

[ReplicaX]

Yep, whatever works for your needs. Options are a good thing

[FrancoB]

I was wondering if this would work, just to neaten the wiring up a little:



Also, I have read about adding a diode to the triggering voltage terminals of the relay to stop EMF building up. If I was to add a diode in this new arrangement would I add it to the 86 and 85 terminals of the '12v' relay or to the 86 terminal of the '12v' relay and the 85 terminal of the '3.3v' relay?

[ReplicaX]

85 has to goto ground on all relays for the relay to even function. I'll have to read about diodes as I've never used them with relays.

[FrancoB]

Ah, ok thanks. I'll go back to the original wiring plan then. In that case I would use a diode on each relay.

I read about the diaodes on a post at BYOAC [here].

I'm not taking it as gospel though, hence asking here too.

[ReplicaX]

What he is referring to is Magnetic Field Collapse. A diode in place would stop any reverse induction. Call it a protection measure for your power supply.

[invzim]

I've messed up a few PSU's when playing around with relays , so yes, you need a diode. What happens when you turn the relay on (or off), is that you actually produce electricity - like a dynamo, which you don't want to send back to the PSU the wrong way. A diode is just that, it assures that electricity flows in one direction only.

[FrancoB]

Cheers d00d ( )

I have all the relays, diodes and switch. I'm just waiting for some wire to arrive and then I'll have a play. I'll check that I'm getting the right outputs from the relays with a meter before I wire them up to the mobo etc.

[ReplicaX]

Cheers d00d ( )

I have all the relays, diodes and switch. I'm just waiting for some wire to arrive and then I'll have a play. I'll check that I'm getting the right outputs from the relays with a meter before I wire them up to the mobo etc.

Nice, let us know how ya make out.

[FrancoB]

Sorted

I was originally going to use three SPDT relays to switch the 3.3v, 5v and 12v between the Naomi mobo and Namco Jamma>JVS but this would have meant that one of the devices would have been switched on at all times. If I have my PC or consoles connected I won't need either device on so I decided two use six normally open SPST relays, three for each device.

I mounted the relays in two banks with some stainless tube and M6x110 bolts:





I then chopped up a couple of power extension cables and wired them to the relays:









The two female JST connectors near the relay is where the Sun ATX male JST connectors plug in. Two sets of male JST connectors running from the relays then plug into the Naomi mobo and Namco Jamma>JVS. I wired the diodes in across the switching contacts as suggested.

The two banks of 12v relays are powered from the Sun PSU and controlled by two SPST rocker switches. I could have used one SPDT switch but the SPDT switches are black and white and will fit in nicely in the custom panel inside the CP. I'll add a couple of LEDs to show when they are switched on.





The wiring will be tidied up a little more once everything is installed.

I tested the voltage outputs with a multimeter and everything works as expected. I plugged the connectors into the mobo and converter and they both turn on/off with the relative switch.

Thanks for the help guys