A very simple DC/MAME question

[Gopherboy]

Hi all,


I realise that this subject is the source of much banging of heads against walls and repeated advice, however, all of it seems aimed at mounted panels, not stand alone ones.

I want to wire my controls to both an IPAC and a DC controller by way of using a barrier strip / terminal block with the buttons connected to one side and wires for both the DC hack and IPAC coming out the other.

There would be two (well, 2 DC + 1 PC) outputs and only one would be plugged in at any time (I.e - only DCs or only the PC.). Does this change things in terms of needing a switch? I thought it would as without the gnd from the IPAC connected to the PC, it would not complete the circuit so no current would run through it. Vice-versa for the DC.

I figured that seeing as the DC and IPAC are in parrallel, there should be no problem with the IPAC circuit not being complete and it should work correctly.

Please let me know if this would be the case - I have read all the post I could find and am led to believe that these discussions are all for having both outputs plugged in at the same time. My instinct and electronics knowledge would have me think that in this case, it would not be a problem.


thanks!

gopher.

[SirPoonga]

Two approaches, either the DC or the PC can be on, but not at the same time, or oyu have  way of switching controls COMPLETELY from one system (circuit) to the other.

[Gopherboy]

So, just to get that absolutely straight - my plan will work so long as only one output is plugged in at a time - without any switches?


thanks!

gb

[eightbit]

I've read many threads on this topic and I don't think any has gotten it to work if both interfaces are plugged in at the same time. Not just unplugging the outputs. The consensus seems to be that you can't have both interfaces wired in parralell. Besides if your going to plug in something any way why not just move the plug to between the interface and the controls then leave the interface plugged into the device. This also gives the flexibility of putting the plug somewhere convenient instead of the keyboard port on the PC or the joystick port on the dc.

Maybe SiRp can clarify what he was saying. I think there is also a danger of burning up both interfaces if you plug them in and  have them on at the same time.

[SirPoonga]

What I am saying is it is dangerous have have BOTH DC and PC hooked up to the same controls at the same time.    IF you do that you ABSOLUTELY have to make sure you don;t have them both on at the same time.

So it would be wise to have way of switching between the dc and the pc, say making the controls pluggable.

[DanU]

I will say that at one point I had this working.

It was the opposite of what I thought and what everybody has been saying - BOTH keyboard and DC HAD to be plugged in at the same time or else the controls were flakey. I used it this way for a good long while, and worked fine. Then, I ended up changing something around, thought I put it back together the same way, but it never worked again. I had to rewire it with a switch, which I had intended to do in the first place, but got lazy and tried the "wrong" way to see what would happen. I've since heard of people frying the bus on their DC this way, so I guess I got lucky.

Use a switch. It isn't that much more work.
Dan

[Gopherboy]

Well thanks for all the advice - even if it wasn't what I wanted to hear!!!

Problem is that the Playstation control needs 28 inputs for the 2 players, and while I can find adequate crimp d-sub plugs/sockets, I can't find a switch any larger than 25 pin!!!

But, not to worry - I will just plug and un-plug internally. Now I feel vindicated in my decision to hinge the top panel, despite a few posts telling me not to!!! It would be nice to have a switch that poked through the side panel but it would mostly be used to MAME and only occasionally for the DC/PS2 so I suppose it is better without the unsightly knob!

Many thanks for all your help everyone!!!


Gopher.
(in for a whole lot more crimping    )