# How to turn on power supply



## choppa (Jun 7, 2011)

Hi everyone,

Not sure if this is the right area, but after a few searches most power supply questions were posted in here so I thought it would be a great place to start.

I have a Dell A870p (07NVX8) server power supply and am looking for information on how to turn it on without putting it into the server. I am hoping to use this as a stand alone power supply for my hobby. From what information I have found it appears that if I bridge a few of the smaller pins (pson, pskill) then the PS should be tricked into thinking it is in a server and power up on its own. 

So I am hoping someone on here might know the pinout diagram for the 24pin block. I have attached pics to show the exact model.


----------



## hat (Jun 7, 2011)

Get a paper clip, and connect the green wire to any ground wire (black).


----------



## choppa (Jun 7, 2011)

Hat, thanks for the help but how do I know which one is the green or black wire?

I do not have the server it came from, a mate who works in IT just gave me the ps on its own.


----------



## Asylum (Jun 7, 2011)

Do you not have the wire harnest that goes with it?


----------



## choppa (Jun 7, 2011)

Asylum,

No I do not have the wiring harness, just the actual ps as seen in the pic.

Would it make things easier if I had a harness? where about's can I buy one from?


----------



## Asylum (Jun 7, 2011)

Yes you will need it to operate the PSU and to hook it to your other hardware.

You will need to find one before it will be any use to you.

Dont have much knowledge on server PSU's maybe someone else can help you.


----------



## streetfighter 2 (Jun 7, 2011)

The PSU is proprietary.  It's also a server PSU so the closest thing it has to a wiring harness is the server chassis.  Have a look at the tech guide for more info.

Personally I'd open it up and have a look at it.  Chances are you can manually trip a relay or jumper a couple solder joints and get it to turn on.  Either that or Dell published some useful info that I can't find with google .


choppa said:


> I was hoping someone might know what each of the pins in the small block of 24 pins is for (see pic), you know like a pinout diagram. Once i have this there is plenty of information on which pins to bridge to turn on the ps, adjust output voltage and control the fan speed.


As I said a second ago, *it's proprietary and the pinout does not appear to be publicly documented*.  You can try and figure it out yourself or you can ask Dell for help.


----------



## choppa (Jun 7, 2011)

Thanks guys for the advise,

I have opened it up to have look inside but this doesnt give me any info on which pins to bridge to fire up the ps. I was hoping someone might know what each of the pins in the small block of 24 pins is for (see pic), you know like a pinout diagram. Once i have this there is plenty of information on which pins to bridge to turn on the ps, adjust output voltage and control the fan speed.

This ps will not be used in a server or pc, it will be a stand alone ps used to power a LiPo battery charger.


----------



## erocker (Jun 7, 2011)

As hat said, use a paper clip, wrap it up in some electrical tape if you wish.

http://www.overclock.net/faqs/96712-how-jump-start-power-supply-psu.html


----------



## choppa (Jun 7, 2011)

erocker,

Thanks for that, I understand that I have to bridge wires to turn on the ps, what I need to know is which of the 24 pins do I need to bridge to turn it on?


----------



## Batou1986 (Jun 7, 2011)

Here  all i did was google the model number someone on rcgroups did the work for you on one of the dual versions of that psu
http://www.rcgroups.com/forums/attachment.php?attachmentid=3955180

The pin out should still be the same on yours
also the pic u used was from a member nightrider73 on rc groups you could try pm'ing him there to see if he knows the exact pinout


----------



## choppa (Jun 7, 2011)

Batou1986, 
Thank you for this. I actually posted on that thread (nightrider73), but no one was able to help me with the pinout diagram. I have tried to bridge the wires as shown in the pic but it did not turn on the ps.

As can be seen in that thread the ps will be used to power a high current battery charger.

The guys on rcgroups have worked out a couple different dell ps to mine and also a couple HP ones. The reason i am chasing the pinout for this one is I got it for free and it is supposed to put out 70 amps at 12v.

I have contacted Dell directly but due to liability issue they wont tell me which pins do what. Personally i dont see the logic in this, give a customer the pinout so they know what wires do what or not give them out so people experiment blindly. Sort of shame to throw out a brand new power supply.


----------



## Batou1986 (Jun 7, 2011)

Try different combinations of that pinout it may have been rotated 180* 

Also no pin on that should be HV so take your multimeter  ground one probe and start touching the pins till you find one with voltage compare its location to the one on the other psu and you should be able to figure out which ones to jump

Edit: the voltage should be less then 5v im guessing here but .05v~1.5v  should be about right, also look around for a small button switch that can be pressed with a paper clip those test switches seem to be a common feature on those PSU's

So are you flyin or drivin ?

Edit edit 

Call dell business support number explain that you are a tech for "make up name here" and your at a customers office and need to test to be sure  powersupply is faulty before the customer will order a replacement and need the pinout to do so they should help you.


----------



## choppa (Jun 7, 2011)

Thanks for the tip Batou1986, 
I will try this tonight and see if it gets things going.


----------



## hat (Jun 7, 2011)

Look at the 24 pin connector. There should be one green wire. This is the power on sensor. It detects a signal sent when you hit the power on switch on the case. This can also be faked by sticking a paper clip in the pin with the green wire, and any ground pin (black wire). You should have the switch at the back of the psu off when you do this, then flip it on after the clip is in to make it come alive.


----------



## Hellraiser1981 (Jun 10, 2011)

Personally i would hook one end of a ~1k resistor to gnd.  Probe each wire with the other end.  when u find PS-on it will turn on.  1kohm should be enough resistance to not kill 5vsb if u stumble upon it but should still trigger turn on (couple mA maybe)  some older compaqs used proprietary pinout and colors.  worked for me.

edit: After further review of the pic, might need some kind of digital signal (control).  might need more tech info to turn it on.  70A @ 12v?? insane!


----------



## erocker (Jun 10, 2011)

erocker said:


> As hat said, use a paper clip, wrap it up in some electrical tape if you wish.
> 
> http://www.overclock.net/faqs/96712-how-jump-start-power-supply-psu.html





choppa said:


> erocker,
> 
> Thanks for that, I understand that I have to bridge wires to turn on the ps, what I need to know is which of the 24 pins do I need to bridge to turn it on?



It clearly shows you in the picture. I don't know how much more clearly it needs to be shown? I mean, I can understand which wires just by looking at the picture.


----------



## newtekie1 (Jun 10, 2011)

Do as Batou1986 says, and take note that the pinout is rotated 180°, and you have bridge both pins to eachother and to ground at the same time(3 connections total).



erocker said:


> It clearly shows you in the picture. I don't know how much more clearly it needs to be shown? I mean, I can understand which wires just by looking at the picture.



Maybe you should look at his pictures, he doesn't have a standard ATX PSU, so there is no 24-pin connector.:shadedshu


----------



## Hellraiser1981 (Jun 11, 2011)

just have to say.... does anyone even look at the pics??  There is no 20 or 24 pin harness, just a bunch of pins that connect to the *backplane?* for the MB.  No wires, etc.
if u were to disassemble the ps, it would be the only pin that connects to an op amp *input* in the PS.   also should measure a couple volts on a dmm with no load and psu plugged in.


----------

