Power Supply A Guide to 12V PSU

REVOCCASES

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I had a bit of success connecting CPU or GPU to 12V bypassing the PicoPSU and solving the ALWAYS ON problem.

Using a cheap solid state relay module I was able to switch the 12V rail (for CPU or GPU) on and off together with the PC.



Only issue with the module I tested is the voltage drop under load since it is only rated for 5A. The PC didn't freeze or something but that voltage drop is far from ideal. Next I'm going to try a other relay board and some better, higher rated SSR.

 
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Advokatrix

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Note, doing so will cause the whole gpu being stuck on problem.

I am aware of this but I asked around regarding this problem and I got the following reply "The GPU has a standby controlled from the PCIE key."
So it should not matter than?!
 

REVOCCASES

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I am aware of this but I asked around regarding this problem and I got the following reply "The GPU has a standby controlled from the PCIE key."
So it should not matter than?!

I had the same issue with one of my setups and the fans of the graphics card kept spinning at full speed when the PC was switched off. The GPU will actually not be active but it can cause weird behavior like that. Just try it out.
 

Advokatrix

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I had the same issue with one of my setups and the fans of the graphics card kept spinning at full speed when the PC was switched off. The GPU will actually not be active but it can cause weird behavior like that. Just try it out.

I am in the middle of soldering. Just hoping not to wreck anything o_O Maybe tonight I have a try, if I get everything completed today. If the fan is spinning all the time, I can turn off the switch on my extension lead. I guess its learning by doing time!
 

REVOCCASES

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I am in the middle of soldering. Just hoping not to wreck anything o_O Maybe tonight I have a try, if I get everything completed today. If the fan is spinning all the time, I can turn off the switch on my extension lead. I guess its learning by doing time!

That's the spirit. ?

If you don't mix up + and - or voltages everything should be fine. Usually I'm always checking everything twice before powering it up.

Good luck and let us know how it worked out. :)
 

Advokatrix

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That's the spirit. ?

If you don't mix up + and - or voltages everything should be fine. Usually I'm always checking everything twice before powering it up.

Good luck and let us know how it worked out. :)

Now, everything is powering up normally... got CPU and GPU fans spinning normally but I do get following message on my screen:

"please power down and connect the pcie power cables for this graphics card"

I dont understand why this is happening. Do I have to solder the pin 5 of 6 which is "sense" to somewhere? I just left it out for now. By the way, the message above is getting put out by the GPU, so it is getting power for sure and it pushes out a signal too... System power draw is around 50w which is fine for GPU + CPU etc.

 
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REVOCCASES

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Now, everything is powering up normally... got CPU and GPU fans spinning normally but I do get following message on my screen:

"please power down and connect the pcie power cables for this graphics card"

I dont understand why this is happening. Do I have to solder the pin 5 of 6 which is "sense" to somewhere? I just left it out for now. By the way, the message above is getting put out by the GPU, so it is getting power for sure and it pushes out a signal too... System power draw is around 50w which is fine for GPU + CPU etc.


AFAIK the sense wires must also be connected to GND.

So if you have a 6 pin connector: 4, 5, 6 go to GND.

 

Advokatrix

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Success! All running fine... played some games for test and no more power reset. Even the fan of my GTX 1650s is not running and stops when I do shut down the PC. It is not drawing extra power since the system power draw in off mode is 2-3w (just like before).
My soldering jobs are really not good but the electrical tape and heat shrink is conceal it nicely.

@REVOCCASES
Thank you soooo much for your quick answers!
:cool: :thumb:
 

chx

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May 18, 2016
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Dell DA-2 + PCI6EPS428 + PicoPSU 160 XT: complete success. The six pin fits as described in https://egpu.io/forums/psu-cables/us3-dell-da-2-pcie-splitter/ and then I taped one of the P4 back close to the Dell - 6 pin connector and used one of the ground connections from it to run a wire into the Remote for the Dell to switch the Dell on. A pre-crimped wire would be perfect but moddiy doesn't send airmail to Canad due to covid and Mouser/Digikey are out of mini fit jr pre crimped wires until December (if anyone in North America has a few to sell please let me know). The other P4 runs straight into the PicoPSU. You need to click the album, the embed it would seem does not pick up my changes. There are three images.
 
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Advokatrix

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Dec 29, 2017
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Success! All running fine... played some games for test and no more power reset. Even the fan of my GTX 1650s is not running and stops when I do shut down the PC. It is not drawing extra power since the system power draw in off mode is 2-3w (just like before).
My soldering jobs are really not good but the electrical tape and heat shrink is conceal it nicely.

@REVOCCASES
Thank you soooo much for your quick answers!
:cool: :thumb:

UPDATE!

I experience radom shut downs and freezes again :mad:

First, I though it was the MX500 SSD thats getting too hot or the riser cable is introducing some issues. Now, I just switched out the Pico160xt for a standard ATX PSU and it seems to run smoothly again (further testing is required). I had no issues for almost a month with the Pico. I reduced the power target of the 1650s down to 70% but I still suffered from image/operating system freezes or shut downs. Rebooting wasnt possible right after those incidents. Judging from the fan speed, the PC tried to boot but couldnt get even into the BIOS, so it looped. After couple of hours of leaving the PC off, I were able to power it up again, just to find it crashing again while Spotify, Firefox and Inkscape were running.

I guess the single brick pico solution is too weak for 2x8GB, i5-8400, MX500 M.2 SSD, GTX 1650 Super (even at 70% power target) :mad:
So I have to buy a second Adaptec PSU or downgrade to a regular GTX 1650. The latter might be the most economic option I guess. Having two 192w PSUs defeats the purpose of my 3.9L case.

Or maybe I have a look into the MeanWell options and build a custom external PSU out of it, using the Pico DC/ATX adaptor.

But for now, the Pico is going back on the shelf again!

EDIT: It is not the Pico causing that issue! Same stuff is happening with my known good ATX PSU. Seems to be a different problem.
 
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enteNT

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Sep 20, 2020
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Hi everyone!

I am currently preparing my 12V PSU for my upcoming sub-4L-build. I got myself the Mean Well RPS-200-12-C and picoPSU 160XT.

The RPS-200-12 has a 6-pin as output and the middle 4 are supposed to be used to build the 4-pin adapter. From what I read in this thread, the pins of the output are connected inside the meanwell. The following wiring alternatives should be equivalent:

1) Using the suggested wiring with 4-pin molex (Link) to plug in to picoPSU.
2) Connecting wires one by one (given the correct +/- connenctions)
3) Soldering 2 by 2 wires together.

Can someone tell me if my thinking is wrong? Does any of those options have any advantages/disadvantages apart from 1) having an additional plug? Thanks in advance!
 

Valantar

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Jan 20, 2018
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I would definitely invest the $30 or so that a decent crimper costs (good ones are more like $60) - crimping wires is so much quicker and easier than soldering.
 

BaK

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RPS-400 and 500 have the following connector for PS-ON and 5Vsb:


Any clue where to order this TKP DH2L-2X2 male housing and the female TKP terminals that go with it?

Maybe there are other keywords to search for equivalent?
No luck so far with 'TKP' on Mouser, Digi-Key, Ali or ebay.
 

Thehack

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RPS-400 and 500 have the following connector for PS-ON and 5Vsb:


Any clue where to order this TKP DH2L-2X2 male housing and the female TKP terminals that go with it?

Maybe there are other keywords to search for equivalent?
No luck so far with 'TKP' on Mouser, Digi-Key, Ali or ebay.

They're available on digikey. Here is the part#.

DF11-4DS-2C
 

BaK

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I am now looking at the available connectors for the AC part, the smallest the best.
There is of course the C14


The Shurter C6 was also brought up in this thread I believe


And in the M2426 I also see:
  • 4X screw terminal, 4 pin Hirose
Fits Meanwell RPS-300-12, RPS-400-12

What is this 4 pin Hirose you are refering to? Another option for an AC connector?
 

Thehack

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I am now looking at the available connectors for the AC part, the smallest the best.
There is of course the C14


The Shurter C6 was also brought up in this thread I believe


And in the M2426 I also see:


What is this 4 pin Hirose you are refering to? Another option for an AC connector?

The Hirose is the name of connector you were looking for.
 
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