Hooking up a button to turn on my motherboard.

[DaOld Man]

*Warning* Whenever you do any work like this on a motherboard, make sure all power has been turned off for a few minutes. Also be aware that static electricity is a silent killer of these boards,
so always observe static precautions. Touch something that is grounded before touching the board. Also remember that even though the power is unplugged, there is still that little CMOS watch battery that has 3 volts on the circuit, so be careful not to lay the board on any metal things, unless that battery has been removed for a few minutes.
Read up on static preventions while working on electronics.
I like to place the motherboard (if it is not in the PC case) on my electric cooking stove, which is cool. Then I touch the stove before touching the board or any parts. I always unplug it from the power supply and remove the CMOS battery first.
AND ALWAYS BE SAFE!!
Better safe    than sorry 

I am thinking about starting this post to explain ways to hook up external buttons to a mother board to turn it on.
I know this subject is brought up several times on here and I thought it would be nice to have the info in one place so it wont be scattered all over the forum like it is now.
First a little crappy diagram of how to hook a happ type pushbutton to the motherboard.
Now where I need everyone's help is here.
I would like to post a picture of a motherboard, its type and number, then a close up of the connection terminals on the board and the pic marked as to show what two pins the wires from the switch connect to.
If you have a picture like this, or can get one off the web, please post it here.
If there is enough interest I can make this a sticky, if not I can delete it.
First, my crappy diagram of how the pushbutton will wire up:
(This may not apply to all motherboards but will work for most.)

[PL1]

Sounds like a good idea.

Maybe we can consolidate the info and related links here in the wiki.


Scott

[DaOld Man]

Please note that dell may use different motherboards and just because you have a 4550 don't necessarily mean you have the version of the motherboard posted here.
That being said, first pic is the motherboard for ID purposes.
2nd pic is a close up of the FP (Front Panel) connector.
Third pic is a connector I salvaged from and old PC case. It used to supply an led on the front of the case. I cut off the led and attach the two wires to my new pushbutton.
These connectors seem to work good for this purpose.
On this motherboard, power switch connections are pins 18 and 20.
The 34 pins in this connector have two rows, row next to back of the board are odd numbers, other row is even numbers.
About this certain board: A ribbon cable originally plugged into this connector.
The ribbon cable ran to a small board on the front with usb and audio ports.
The power on switch has another smaller ribbon cable that plugs into this small usb board.
This makes the job more confusing and even more difficult to tie your new button to the PC case button, so it will probably be easier to connect directly to the MB FP connector.

[DaOld Man]

Sounds like a good idea.

Maybe we can consolidate the info and related links here in the wiki.


Scott

I like that idea.

[JDFan]

Here's a general one using a Gigabyte MOBO manual.

[bfauska]

I've been off the forums for so long now that my project thread is 4 years old... but in it I had a modified version of this idea that I think is worth sharing. I've quoted it rather than retype it, I don't remember the brand or model of the MB but I doubt anyone is using the same one anyway. The switch is just hooked up to the pins used for the case switch.

This is a picture to try to explain how I hooked up my "Enter" button on the CP to power up the cabinet and then return to it's mild-mannered-life as a lowly "Enter" button.



This same task could be accomplished easily if your MB supported power-up from password, but since mine doesn't I had to wire the power-on header to an arcade button (nothing new I know) and then I wanted it to become the enter button when in the frontend (that's the new part.) In the future I will also use this relay to power on the speakers and marquee. As for now, it's wired as shown in the picture. When the relay is off (no power to the coil) the MB power is connected to the button on the CP, when the button on the CP is pressed it turns on the computer and the coil of the relay is powered up from the PSU, switching the connection to the button over to the encoder instead of the MB. I initially hooked it up to only use one leg of the switch and leave the ground hooked up the whole time but that didn't seem to work, so I switched both legs. I should be able to switch one leg of the power for the marquee and speakers later and still have one pole of the relay left so that I can illuminate the power button from a wall-wort or battery when the computer is off and then connect it up to an LEDwiz when I power it up. I shut the computer down using a shifted key combination and windows shutdown, so I don't need the power button while the computer is running. I did leave the original PC power button wired before the relay so that I can always use it if the computer locks up.

[DaOld Man]

This board is an IBM, couldn't find the model number right off the bat.
This board is different from most boards by having a double pole button to turn it on.
I don't know why they do this, but I have found a single pole button will work just as well, just connect it to one of the dual switch pins.
Also this board has the front panel connector pins clearly identified. Most motherboards do have this printed near the connector. It makes the job a lot easier.
The first pic is the mother board for ID purposes.
You can see the FP connector plugged in. It may be easier to just connect your new button to the existing wires on the front panel. The wires going to the switch are two yellows and two blacks.
Just connect to a yellow and black pair and you should be ok. Make sure you are connecting to the power button though, because the power on led also has a yellow and black wire going to it.
Second pic is my two pin connector plugged into one of the PWR SW pair of pins. You can see the pinout printed on the MB here too.
A board like this is very easy to hack for an external power button.
Pretty solid board too. Very hefty CPU heat sink, but I found the north bridge (smaller heat sink beside the large cpu heatsink), was running pretty warm (around 110 F.) So I may add a fan to it, even though it originally does not have one.

[DaOld Man]

Ok, here is a Dell OptiPlex GX520. This is a very small and compact computer.
I didn't want to mess with the FP connector on this one, because the ribbon cable supplied two USB ports, audio jacks, and the power switch.
And since I didn't want to decase this one, I decided to leave the power switch in it.
Now, here lies the problem I encountered. I could not get the little board with the switch, usb plugs, and audio jacks out of the case. (See first pic).
I searched the internet for an easy way to do this but didn't find any answers. In the photo you can see a screw. I removed the screw and the board would still not come out.
It would rock a little, but would not come out.
There is another screw in the board, but it is covered by a part of the chassis.
After removing all the covers I could, I still couldn't figure out how to get that darned little board out.
But I did figure it out, and here is how you do it.
Remove the hard drive, unplug it and lay it aside. Remove the CPU heatsink. (Two screws that go through the motherboard.)
Unplug the power supply from the motherboard. Remove the mother board (I just removed all screws and pulled it up out of the way a little.)
Remove the CPU fan. (Plastic clips)
Remove the one screw in that little power switch board.
Now you can pull the board up and back towards the motherboard.
The cable to it is in a bracket, have to twist the cable a little and pull up and out of the bracket.
Now you can pull the board out, turn it to get to the component side.
The switch button is on the opposite side, but now you can solder two wires to the switch's posts that come through the board. (Second pic).
 I used some hot glue to secure the two new wires to the circuit board (not in pic).
Now just reassemble everything.
Clean up all the old CPU heat sink paste from heat sink and CPU. (I also washed out the heatsink with warm soapy water. It wasn't clogged up but had some dust in it. I allowed it to dry completely).
Apply new heat sink paste and install heat sink.
Install hard drive.
I also tapped onto the yellow and black wire going to the hard drive to supply a 12 volt relay outside the case. This relay will turn on the monitor and whatever when PC turns on.
This was the only power plug in the case (besides mother board connectors), and it was sata.
The more I work on dell PCs in this hobby, the more I hate them.
But now I have wires to run to my happ pushbutton to turn on the cab, and I have 12 volts out for a relay.

[Alaska]

I just worked on this in another forum located here http://forum.arcadecontrols.com/index.php/topic,148167.0.html. I have a Dell optiplex that is slightly different than some of the other models. The on/off switch is located on the board with the USB and audio jacks. I was able to get the button to work by soldering it to the bottom of the existing board. Jump over to the other forum to see a lengthy discussion that might help you out with your button wiring issues.

Cheers