Hacking a power button on a PC

[mrracer]

Can anyone please advice on how to hack a Dell Dimension 4550 power button to an external switch I want to mount outside my cabinet. I had a compaq in the cabinet before, and that was easy cut the power cable connected to the power button and connect it to the external wiring. With the Dell it seem to be using a signal cable, and I dont know which cables to use as the power source. Any help would be greatly appreciated.

[SirPoonga]

Do you know what motherboard Dell uses, should be marked somewhere on the board.  Get the manual for it to see where power switch plugs in.

[Stobe]

Like SirPoonga was saying.  I would find it odd if the motherboard didn't have the standard 2 pin power header for the power switch.

Then if you have an old computer somewhere, you can rip the 2 pin cable from wither the power switch or one of the LED cables (IDE activity, etc).

If not, you can grab a LED ehader cable from radio shack.  Then just extend it to whatever switch you want to.

Hope this helps,
Stobe

[mrracer]

I'm new to this, I've attached the layout of the motherboard, I'm still not quite sure would that be the "configuration jumper (JH81)"? It seems everything is coming through the "front panel switch connector (J9H2)". Again any help is greatly appreciated, I'm just not sure were to grab the power from...

[sc1103]

Dell uses a proprietary connector, which makes it a pain.  If you open up the front of the computer, there will be two tiny microswitches, and the power one can have the headers extended and attached to a pushbutton.  Alternatively, but dangerous (I fried my mobo  ) you can find the pins through trial and error then solder onto the bottom ***I THINK***.  Saint's "adopted beta page" also has some ignition switch you can buy to do this for you I believe. 

[mrracer]

Great I get the complicated proprietary connector  , I definitely don't want to fry mine (thanks for the heads up) what is the link to Saint's "adopted beta page" so I can have a look at the ignition switch, thanks again for the help? 

[TheVengeance]

If there is an option in the BIOS under the power settings, then altering the switch isn't necessary.

There should be something similar to this under the power options of the board. It might read the following.

PWR-ON after PWR-FAIL. If this is enabled, the system will start automatically when the switch is turned on. At least that's how it is on my PC. I'm using DOS though, so that's really not a problem with the PC just turning it off and on. I have it wired to the power block, so when the marquee, and monitor get juice, so does the pc.

Try looking in your BIOS before making any mods to the switch or PS.

[kinnunenjustin]

LOL...I just did this like an hour ago before seeing the thread...definitly a must for every cab though thats for sure

[TheVengeance]

No mods or anything to my mobo, or PS, simply what I had told you about in the BIOS.

This thread shows a completed pic of my setup, with everything wired to one switch.

http://forum.arcadecontrols.com/index.php?topic=39085.msg352366#msg352366

[SirPoonga]

Are there any marking ont he board by the J9 header?  Like PWR, SPKR, etc...

[mrracer]

The markings state "Front Panel"...

[elvis]

If there is an option in the BIOS under the power settings, then altering the switch isn't necessary.

PWR-ON after PWR-FAIL.

I use this in all my cabs.  Just turn the cabinet on at the wall, and everything powers up.  No need for any power button hacking.

[SirPeale]

If you want the power on your computer to come up when you power up your cab, you can attach a 10uf 16v capacitor to the power on pins.  Just make sure and meter it first to see which pin is '-' and which is '+'.

[sc1103]

Great I get the complicated proprietary connector , I definitely don't want to fry mine (thanks for the heads up) what is the link to Saint's "adopted beta page" so I can have a look at the ignition switch, thanks again for the help?

http://beta.arcadecontrols.com/cabinet-power.shtml

the link is wrong though...I forget how you fix it but i think i changed it from compgeeks.com to just geeks.com or something like that.

[Pik4chu]

The power-on jumper for ATX motherboards (the current standard, the one with the large 20pin molex) is done by shorting the green wire with ANY ground (black) wire. using a momentary pushbutton switch.  All the front panel is is a connection from the green wire to the common ground on the mobo then you connect a switch to those pins on the mobo and you have yourself a power button.  This is a trick used to test PSUs or other devices w/o a mobo, just by sticking a paperclip into the socket for the green wire and then into a socket for a black wire and it starts up.  Note that the momentary pushbutton is only used when conencting to the proper pin on the mobo.  Shorting the wires requires a constant connection (or the use of a relay if you choose).  Which I have done in several PC projects of mine.


Annnnyways, with that information out of the way, the easiest way to do a button hack is take off the front cover and look at the pwr button, note what color wires it uses and trace it back to the PC. Those are the pins you need.  Or simply clip off the pwr button extend each wire to where you want the pwr button to be and re-attach the button and your done. piece of cake.

[mrracer]

Unfortunately I can't use the front power button as the Dell uses a proprietary front power panel. I can't hack it because there are no wires visible and uses a signal cable or ribbon to connect

[SirPeale]

The power-on jumper for ATX motherboards (the current standard, the one with the large 20pin molex) is done by shorting the green wire with ANY ground (black) wire.

The shorting the pins trick may or may not work.  With some motherboards, when you short those pins, it trips the POWER_ON_GOOD and it won't boot.  My capacitor trick works every time.

[mrracer]

Does that only work if I have the PWR-ON after PWR-FAIL option on? Also does that mean I have to shutdown the operating system everytime I want to turn off the cab or can I use a arcade style button with a microswitch or a leaf switch to turn your PC on or off? Now does the capacitor go on the same pin number as mentioned above on the 20 pin matrox cable I have. Which would mean I only need one capacitor, or am I mistaken. I still trying to understand this, since one pin is negative and one is positive were does the negative pin go and were does the positive one go, on the green PS ON wire (maybe the negative pin on the black common wire (any) and one pin "positive" on the green PS ON wire?) Please advise...

[Pik4chu]

The power-on jumper for ATX motherboards (the current standard, the one with the large 20pin molex) is done by shorting the green wire with ANY ground (black) wire.

The shorting the pins trick may or may not work.

[mrracer]

Hey Pik4chu, I appreciate the response. I cracked the Dell open (pretty difficult to take out the plastic casing I might add, ended up braking one of the tabs off) and finally got to the power button, unfortunately in this particular model I guess there are no wires to trace to the mobo it's soldered on the a board and the only thing I can trace back are the 2 ribbons attached too it. Trust me I much take that route much simpler for me. But undoable... That's why I've been looking at your other alternative, which I'm ready to try but I just want to make sure i do it right. If I understand you correctly I would run one wire from the green wire to my push button and a common black wire to the push button as well, is this correct. Sorry I wound repetitive, but like I mentioned before I don't want to fry the mobo since this is my first time actually trying something like this. Thanks again.

[quarterback]

If you want the power on your computer to come up when you power up your cab, you can attach a 10uf 16v capacitor to the power on pins.

[Pik4chu]

If you want the power on your computer to come up when you power up your cab, you can attach a 10uf 16v capacitor to the power on pins.

[Pik4chu]

Hey Pik4chu, I appreciate the response. I cracked the Dell open (pretty difficult to take out the plastic casing I might add, ended up braking one of the tabs off) and finally got to the power button, unfortunately in this particular model I guess there are no wires to trace to the mobo it's soldered on the a board and the only thing I can trace back are the 2 ribbons attached too it. Trust me I much take that route much simpler for me. But undoable... That's why I've been looking at your other alternative, which I'm ready to try but I just want to make sure i do it right. If I understand you correctly I would run one wire from the green wire to my push button and a common black wire to the push button as well, is this correct. Sorry I wound repetitive, but like I mentioned before I don't want to fry the mobo since this is my first time actually trying something like this. Thanks again.

ok, its one of those models.


hmmm does the connector look like this? http://www.broadbandreports.com/r0/download/379959~1887fd19525860a4b51fa4e62353e6aa/thesolutionmaybe.jpg or is it bigger?

Also, look on the mobo for an Intel part number and you can likely find hte pin-outs on intels site using that.  I am obviously trying to avoid shorting the green wire solution as much as possible,  Because while it works great w/o a mobo, havent (needed to) used it all that much with a working motherboard. 

[mrracer]

I opened the link but no picture? I took a look at the Intel site for the E210882 mobo no luck yet. So I took some pics and wrote comments on it, hope this helps, thanks again.

[SirPeale]

If you want the power on your computer to come up when you power up your cab, you can attach a 10uf 16v capacitor to the power on pins.  Just make sure and meter it first to see which pin is '-' and which is '+'.

Why does this work?  What's the cap doing exactly?
Thanks

As far as I can tell it doesn't unless he is assuming you are powering your cab with the same psu as your computer, even then it doesnt sound right...

Ah, the dissenting voice of inexperience.  It does work, and works well.  I've done it on several cabinets now.

A capacitors uncharged state is shorted.  So when you turn on the power to your cabinet, the cap shorts out the power on pins momentarily.  After it charges, the capacitor becomes open, allowing the board to boot.  You have to use a *very* small capacitor (ie 10uf) for this to work.  You also have to get the polarity correct, so you have to measure the pins on the motherboard to see which pin is negative and so on.

As for 'powering the cab with the same PSU as the computer' well...what else is powering the cab?  A gaggle of hamsters on wheels?  You're getting the power from the PSU to power the computer and perhaps some 12V lights, but power for the monitor and marquee better be coming from mains power.

[Pik4chu]

If you want the power on your computer to come up when you power up your cab, you can attach a 10uf 16v capacitor to the power on pins.

[SirPeale]

no need to be condescending simply because we cant understand your (vague) instructions   Perhaps a drawing of where the cap actually goes because it still doesnt make sense to me.  Or even a picture of this installed would be nice.

I'm not being condescending, and I've given rather detailed instructions.  I've stated that the cap goes on to the power on switch pins.  A picture wouldn't work, because it varies from keyboard to keyboard.  Actually...now that I think about it, I did post a picture some months back of it in place, let's see if I can find it...

Ah...



No, that's not it, but it give a good diagram of what I've done.  Let's keep looking...

Ah, here we go:

http://forum.arcadecontrols.com/index.php?topic=19304.msg163629#msg163629

I tackled this problem a year ago.  Got a four page thread out of it.

[Pik4chu]

no need to be condescending simply because we cant understand your (vague) instructions

[rescue161]

It really shouldn't be that hard...

Unplug the ribbon cable from the MB, then take an Ohm meter and test which leads short when the power button is pressed. Problem solved.

[SirPeale]

It really shouldn't be that hard...

Unplug the ribbon cable from the MB, then take an Ohm meter and test which leads short when the power button is pressed. Problem solved.

Your simple solution has many, many flaws.  So many I'm not going to list them here!  Begone, I have thwarted your plans!













(Okay, that's a good idea.)

[mrracer]

Well I got back into the front panel took the PC apart and took pictures of the front power button panel. Unfortunately I can't really try anything until I or someone helps me on determining the positive and negative leads on this board. I've attached some pictures of the back and front of the panel.  hopefully you guys can figure it out by just looking at it!? Please let me know what other info you need. 

The mobo number was engraved on the mobo (was not on a sticker) Did I grab the wrong one? 

[SirPeale]

We're talking about the leads on the motherboard itself, not the PCB with the switch.  You could just remove the switch and solder a cap in it's place.  You can't tell by looking at it which is positive and which is negative, you'll need a multimeter to determine that.  Put a lead on each leg of the switch.  If the number is positive, then whatever the black lead is on is the negative one.  And if it's negative, it's obviously the opposite one.

And yes, the computer must be plugged in to get this reading.  If you feel uncomfortable with this...well, I can't help you there.

[SirPoonga]

I opened the link but no picture? I took a look at the Intel site for the E210882 mobo no luck yet. So I took some pics and wrote comments on it, hope this helps, thanks again.

that shouldn;t be to hard to figure out which pin on the ribbon cable is power and ground.  Get a continuity tester (like one on a multimeter), take off the cable form the little circuit board and start testing the header with the switch to find out which pins are the power.  Then, if you use a razor and cut the ribbon cable you can splice into those wires.

[mrracer]

Thanks SirPoonga, I went ahead and just took out the front panel based on the circuitry in the back and the position of the powerbutton I was able to determine the positioning of the power and common lead, I went ahead and checked it with a continuity tester just to make sure of the positive and the negative and soldered two cables to the back of the panel and ran them to the push button on my cab. It's working great. Now that I have that working...
I'm enthralled by the idea of using a "capacitor" to short out the push button, I'm just still not quite sure (based on the instructions) on how to properly do this.
Since I figured out the power and common on the front panel can I soldered the capacitor to the push button itself and get the same result? Can anyone please confirm this??

[steptoe]

It dosent really matter which is pos or neg, they both go to a button and then switched, as long as you havent changed anything else.

[SirPeale]

Since I figured out the power and common on the front panel can I soldered the capacitor to the push button itself and get the same result? Can anyone please confirm this?? 

I'd remove the button altogether and use the holes and the solder pads to put the capacitor in it's place.

Just remember to meter the pads to see which is the positve lead and which is negative.

It dosent really matter which is pos or neg, they both go to a button and then switched, as long as you havent changed anything else.

Which is good if he was just going to use a switch, he wants to use a cap.  If he doesn't get the polarity correct, best case scenario nothing happens at all, worst the cap goes *pop* and he has to get another cap.

[mrracer]

This is probably a stupid question but I just want to make sure, If I leave the button in place and the wiring I just ran to the button outside the cabinet will the capacitor interfere with any of it. Reason for this is because I want to be able to also power down windows by simply pressing the button outside the cab?

[SirPeale]

I dunno. 

[Pik4chu]

This is probably a stupid question but I just want to make sure, If I leave the button in place and the wiring I just ran to the button outside the cabinet will the capacitor interfere with any of it. Reason for this is because I want to be able to also power down windows by simply pressing the button outside the cab?

I would think so.

[ady]

I've done this on a couple of Dells and it turns out to be pretty simple.  On the small PCB remove the ribbon cable (the one you've labelled as "This ribbon goes to the power button" on your photo) and you should find a standard set of pins for the power, HDD lights, etc (none of them are labelled).  The number of pins here has been different on both the Dells I've worked on so it's a case of plug in a power header and try it, if it doesn't work move onto the next set of pins. 

Of course you'll no longer be able to turn on the PC via the PC power button, but that's not really a problem.