Help - How to wire an Arcade button to Power on PC

[Alaska]

I just snagged an old Dell Optiplex 745 to drop into a MAME. I wanted to wire the on/off button to an Arcade button that I plan to mount next to the monitor on/off switch on the top of my cab. Trouble is ... I can't seem to figure out how to integrate the button. Here are some pics if it helps.

Thanks!

[vwalbridge]

Doesn't look like that motherboard has Power Switch headers/pins. The board does have power sw solder pads near the main power molex but no pins.

Bust out the old solder iron and solder your two wires from the arcade button to the back side of that original case tactile switch. Done.

[PL1]

http://forum.arcadecontrols.com/index.php/topic,128837.0.html


Scott

[monkeybomb]

I hadn't seen the video from that thread, but I did exactly what that guy does on an optiplex 790. I hacked the cable and attached a button the right wires.  It works and powers the computer, but there is an error on the motherboard saying that there is no power switch.  Then I have to hit F1 to boot.  I can't find anything in the bios to allow me to skip the error.   I wish I had simply used the option to boot the computer when it is plugged in.  That option takes 2 minutes to set-up and doesn't require any hacking.

[Alaska]

http://forum.arcadecontrols.com/index.php/topic,128837.0.html


Scott

Thanks Scott. That is a great video, but that version has a separate harness running to the on/off switch.

I hadn't seen the video from that thread, but I did exactly what that guy does on an optiplex 790. I hacked the cable and attached a button the right wires.  It works and powers the computer, but there is an error on the motherboard saying that there is no power switch.  Then I have to hit F1 to boot.  I can't find anything in the bios to allow me to skip the error.   I wish I had simply used the option to boot the computer when it is plugged in.  That option takes 2 minutes to set-up and doesn't require any hacking.

Thanks M-bomb. I had no idea that was an option for the computer to boot when connected to power. I'm going to opt for that setup and have everything wired into an accessible central power unit. Thanks for the knowledge.

[Howard_Casto]

Well that isn't going to be the best option.  Modern operating systems safely shut down when you tap the power button, which is what you want. 

There's a power button on the pc somewhere and two wires go to it....  splice into those two wires and hook that to your pushbutton and you are good to go.  It's so simple a trained monkey could do it. 

[monkeybomb]

I have never had a problem with this before dealing with the optiplexes.  This button is soldered on to that little breakout board, so there's no way for guys with low end soldering skills to tap in there.  So the monkey simple hack has to be between the board and the mobo.  When I did that, I only cut 2 wires and added the button.  It totally works and turns on the PC.  But something in the system isn't happy with it and I have the error, requiring a keypress to continue.

Mala has the option to shutdown windows upon exit, which makes the power thing doable, but I'd still rather have a button if possible.  I am about to use an optiplex on another project. If I am missing something, I would appreciate the training you think the monkey had, so that I can get between the breakout board and the mobo without this error.  At the moment I plan on using the power solution.

[DaOld Man]

Hello Alaska.
If you get it figured out, how about posting a pic of your MB, with model #, and how you did it in this thread:

http://forum.arcadecontrols.com/index.php/topic,142735.0.html

It might help someone later.

[Alaska]

Doesn't look like that motherboard has Power Switch headers/pins. The board does have power sw solder pads near the main power molex but no pins.

Bust out the old solder iron and solder your two wires from the arcade button to the back side of that original case tactile switch. Done.

If I do this and leave the old power button in place do you think that the arcade button would function and the computer would not report the error?

[vwalbridge]

Doesn't look like that motherboard has Power Switch headers/pins. The board does have power sw solder pads near the main power molex but no pins.

Bust out the old solder iron and solder your two wires from the arcade button to the back side of that original case tactile switch. Done.

If I do this and leave the old power button in place do you think that the arcade button would function and the computer would not report the error?

Yes, I would imagine so. That motherboard is probably programmed to look for that "daughter-board" every time it initiates. As long as you leave that daughter-board plugged in and solder the wires to the bottom of the power tactile switch, you should be good.

[Alaska]

Doesn't look like that motherboard has Power Switch headers/pins. The board does have power sw solder pads near the main power molex but no pins.

Bust out the old solder iron and solder your two wires from the arcade button to the back side of that original case tactile switch. Done.

If I do this and leave the old power button in place do you think that the arcade button would function and the computer would not report the error?

Yes, I would imagine so. That motherboard is probably programmed to look for that "daughter-board" every time it initiates. As long as you leave that daughter-board plugged in and solder the wires to the bottom of the power tactile switch, you should be good.

I'll give it a whirl when the buttons get in next week. Thanks for the help!

[JDFan]

OR if you do not want to solder to the board just splice into the proper wires and leave the wires also going to the PCB (rather than cutting the entire thing off like he does in the video.) That way pressing the button will still complete the connection but the connections will still all be in place to avoid the error reporting and the entire thing is still reversable if you decide to change the system later and want your PC back for another use.

[Howard_Casto]

Yeah that's what I was getting at, but he acted like he tried it and it didn't work.  I don't see how it couldn't unless the pcb was removed. 

[Alaska]

OR if you do not want to solder to the board just splice into the proper wires and leave the wires also going to the PCB (rather than cutting the entire thing off like he does in the video.) That way pressing the button will still complete the connection but the connections will still all be in place to avoid the error reporting and the entire thing is still reversable if you decide to change the system later and want your PC back for another use.

That's a great idea. I found this while searching the web that could be super useful. It's a wiring diagram for the harness coming from the motherboard. From the looks of it I should be able to tap the ground (does it matter which one?!) and power (#12) into an arcade button for the fix.



it came from a blog at http://mechanicalphilosopher.blogspot.com/2013/07/using-dell-optiplex-745-motherboard-in.html

[JDFan]

Shouldn't matter which ground you use - to test just get a piece of wire - take the casing off of each end and touch one end to each connection (power and ground) and see if the system starts to boot - if it does you know you have the right 2 spots to splice into.

[monkeybomb]

.

[DaOld Man]

You do not want to tie the pushbutton switch to gnd and power. This will create a direct short.
Or maybe Im missing something?

[Howard_Casto]

Poor choice of words... by power and ground he means the vcc and gnd of the  original power switch, not the power supply.  As I said before ... it's just a switch, two wires go into the switch.... tap into those two wires. 

[vwalbridge]

it's just a switch, two wires go into the switch.... tap into those two wires.

Exactly. There is no reason to make this any more complicated. Hell, bridge the solder posts under the original switch with a flat head screwdriver if your curious. I bet the computer turns right on.

[Alaska]

it's just a switch, two wires go into the switch.... tap into those two wires.

Exactly. There is no reason to make this any more complicated. Hell, bridge the solder posts under the original switch with a flat head screwdriver if your curious. I bet the computer turns right on.

Easy to do and bypass removing the button and cutting the cords. As mentioned

Doesn't look like that motherboard has Power Switch headers/pins. The board does have power sw solder pads near the main power molex but no pins.

Bust out the old solder iron and solder your two wires from the arcade button to the back side of that original case tactile switch. Done.

If I do this and leave the old power button in place do you think that the arcade button would function and the computer would not report the error?

Yes, I would imagine so. That motherboard is probably programmed to look for that "daughter-board" every time it initiates. As long as you leave that daughter-board plugged in and solder the wires to the bottom of the power tactile switch, you should be good.

I'll give it a whirl when the buttons get in next week. Thanks for the help!

I attached two wires to the arcade button then (on the first try) touched the wires to the bottom of the solder points associated with the on off switch. The points that I used were the upper right (power - this can be traced to the power on the harness - slot 12) and the lower right solder point. In the picture below there are four solder points associated with the on/off switch that are located just above the circle. I hit the arcade button, and the unit powers up and auto launches HyperSpin. Now I need to work out the bugs with the emulators and mapping through RocketLauncher and I should be all set to go. Thanks again for the help.