questions for my specific brickless endeavor

[Vorpalbotch]

Completely new to the forum as well as SFF, I am currently trying to figure out how to power my NUC through a sfx power supply. I would prefer to not have to scrap this power supply as it already exists in my possession. The power supply is currently powering a thunderbolt 3 external expansion board as well as an R9 380x, and only has a 24-pin, 6+2 and 6-pin. I have read a little on here about adding a 5.5mm x2.5mm barrel plug to a power supply, but not sure if the one I have can handle powering a my NUC7i7bnb as well as the R9 380x. If it can, any tips on exactly what I need to do? Thanks much in advance.

 

[Blakfetha]

https://ark.intel.com/products/95068/Intel-NUC-Board-NUC7i7BNB
"DC Input Voltage Supported12-19 VDC"
so perhaps you can do something with the 12V rail???

 

[Vorpalbotch]

How do I identify the 12v rail? Sorry just completely new to modding. I had a barrel connector from an old laptop that fits the nuc, just dont know where to splice it in to the power supply.

 

[el01]

I would desolder a 24-pin connector from an old motherboard and then solder a wire to the 12V (I assume the NUC has relatively low power draw), then solder a wire to the ground, then connect those up to the barrel jack.

OR:

and a molex adapter for your power supply.

If all else fails, get a compact power strip, throw that in the case, and connect the power supply and psu to it. It's janky, but it might just work.

 

[Choidebu]

You also need to keep the sfx powered on all the time since the motherboard usually sends ps_on signal to turn it on. Not the case with NUCs. Now I don't know exactly how to do it, but it is doable. Might try googling it.

Additional info:
When a psu is plugged to a wall outlet, only 5VSB (SB = stand by) is powered. When power header is jumped on the board, it sends a momentary ps_on signal to the psu which it then powers all the other rails. On the top of my head that means the ps_on pin needs to be jumped to either gnd or 5vsb, just need to google a proper spec. And also whether or not a simple jumper will work or it needs to be momentary.

 

[el01]

You also need to keep the sfx powered on all the time since the motherboard usually sends ps_on signal to turn it on. Not the case with NUCs. Now I don't know exactly how to do it, but it is doable. Might try googling it.

Additional info:
When a psu is plugged to a wall outlet, only 5VSB (SB = stand by) is powered. When power header is jumped on the board, it sends a momentary ps_on signal to the psu which it then powers all the other rails. On the top of my head that means the ps_on pin needs to be jumped to either gnd or 5vsb, just need to google a proper spec. And also whether or not a simple jumper will work or it needs to be momentary.

Doesn't he already have 24pin to GPU? Will the GPU power the system on?

 

[Choidebu]

True. So it might have some external circuit controlling the psu. Afaik people using multiple psus to power their mining rig resorted to load switches or external switch to turn on their gpu feeding psu.

So if your eGpu box already turns on the psu with a circuit, then you're all set - just need to wire the 12V to a dc jack, then set your bios to wake on power (if it does have thay config)

 

[Vorpalbotch]

True. So it might have some external circuit controlling the psu. Afaik people using multiple psus to power their mining rig resorted to load switches or external switch to turn on their gpu feeding psu.

So if your eGpu box already turns on the psu with a circuit, then you're all set - just need to wire the 12V to a dc jack, then set your bios to wake on power (if it does have thay config)

I believe power is always on as the gpu immediately turns on when the thunderbolt is plugged into the nuc or any other device with thunderbolt. There is no on off switch for the eGPU besides the one on the psu which remains always on.

 

[Choidebu]

Well then wire it up and see if the NUC turns on when you set the bios to wake on power then you turn on the switch on the psu. The psu might have been jumped already to enable all rails when powered from the wall.

 

[Vorpalbotch]

IT IS ALIVE. i had to jump the the pins on the 24 pin to always on but it is alive. the graphics card and the nuc are running off the sfx power supply. this is simply amazing but i have one question, is this safe to have the pins jumped to fool the psu 24/7???

 

[Choidebu]

It is safe. The mining folks have been doing it forever. All it means is that the psu powers all the rails once it receives external power.

Btw, what pins did you end up jumping? Ps_on to gnd?

Add:
Btw you still have one issue: powering it down.