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PC power on/off switch WITHOUT modifying PC motherboard/switch
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markronz:
Sorry to resurrect such an old thread.  I am helping a friend and we are using the same computer the Dell Zino HD.   We have taken apart the PC and see the power switch from the picture right above this.  We just are looking for some confirmation of which wires to use!

The Dell Zino HD power switch has four wires on it.  I assume that two of them are for the LED, and the other two are for the power button, the ones I need to tap into.  I'm just having problems figuring out which 2 wires I need.   

There are labels, sort of, on the mother board.   There is a SW1 label above the power button connector.  This points to the far left pin.  Then underneath the power connector, there are also three more labels (TP49, TP55, and TP88).  I do not know if these three labels apply to the power button connector or not since they are located under it, and not right next to SW1.

My guess is that the far left two wires are the ones I need.  SW1 would seem to imply to me that it's for the power button, and I would think that the wire immediately next to it is the other power button wire.

So, with all that said, do any of you have any idea which two wires it is?  Am I correct in assuming its the far left two wires?  Thanks in advance for any help you can give!
DaOld Man:
Im not sure about the proper wire designation, someone else may, but if you have a multimeter, you can ohm out the wires.
The two switch wires will have infinity on ohms with switch not pressed, but press the switch and the ohms should go very low, near to zero.
If ohms don't change when you press the switch, try another combination.
Once the ohm meter goes form very high to very low when you press the switch, you have the two wires you need.
The pins that these wires plug into on the motherboard are the ones you want to connect your power on button to.
(Or you can cut these two wires and put them on your arcade button.)
If you don't have a digital multimeter, get one. You can get a cheap one, (Radio Shack, web) and it will be very handy.
Get one with a diode checker if you can, then you can check diodes and leds.
markronz:
I know you're right, that would be possible.  I'm personally not so great with a multimeter yet, but I'm learning.  But unfortunately I'm trying to help out my friend over the phone.  He's not a electrical sort of guy either, even less so than me, so I'm not sure that I could even walk him through that over the phone.   So I was hoping we could figure out what wires do what.

I think it's a fair assumption that the two wires next to each other go together.   So, what about from a worst case scenario sort of thing...
1. What would happen if we tap into the wrong two wires and hook up the LED wires to a button.  What would pushing the button do?  Would it short something out?  Or do nothing at all?

2.  What if I'm wrong and the two wires next to each other do not go together.  Worst case scenario, if I hook up the Power + and the Power Switch + to the same button.  What would happen if you push it then?   Definitely don't want to risk it if it would fry the computer or something.

I guess what I'm trying to establish is, what is the worst case scenario if we tap into the wrong set of wires? Or tap into all four and start mixing and matching until we find the right two?
DaOld Man:
As far as hooking up the led leads together, as long as the motherboard is not turned on it shouldn't hurt anything. But I wouldn't try it with the MB on.
Heres an easy way to find what you need.
Cut the four wires going to the button, and plug them into the MB.
With MB off, touch two wires together, if MB doesn't come on, try two more wires. (Sort of like you said about mixing and matching).
Once you found the two wires, mark them, or write down the colors.
The other two wires are the LED wires.
As with hooking either of these wires to power supply, I wouldn't recommend it, since we don't know if the MB uses ground or +5vdc to power on, you could short something out.
Just find the two wires you need and wire them to the button.
Also, most motherboards have the connections marked on the board (PWR SW or PWR ON, PWRLED+ PWRLED-, or something similar.)
You can also look up the manual on the net for that model. Most user manuals have a picture of the terminal and what connects to who.
markronz:
That's some good advice.  Maybe we will splice the left two, which I suspect are the correct two, and touch them together to see if the computer boots up.  I'm glad you mentioned to not do this when the PC is on though.

Unfortunately, there are no clear labels on this mobo though.  There is the SW1 label, which I mentioned before, which points to the first pin.  So that is why I suspect that's the power button one.  But the rest are not clearly labeled.  And unfortunately there do not appear to be any manuals that explain what specific each wire does.  I am guessing because it's a Dell, and because it's a Zino HD, one of those tiny 8x8 box PC's, that it's not as user friendly to mess with when you open it up.   So yeah, I haven't had any luck finding any references that tell me which wire is what.  So that's how I ended up on the mixing and matching scenario.  :P
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