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[GUIDE] Making a molex-to-barrel adapter


jacobsson

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OK @Dschijn, thanks for the suggestion. I tried with a different, 7 year old 550W PSU, which on the first few tries seemed to last slightly longer (5-10 seconds) before cutting out. However the last few tries it's the same story with this PSU: As soon as the load increases to handle 3D graphics the graphics card cuts out after a second or so and the system reboots. The total draw of my setup (Zotac 970 + Akitio) never exceeds 205 Watts, so I'd be really surprised if the Nexus PSU can't handle it. Zotac recommends a 500 W PSU for this card, but that is for a full system, while I am running only a graphics card with an Akitio box.

 

As the Nexus is multi-rail, it could be that the OCP is triggered, but I am not sure why it would happen under these relatively limited loads (I am running an ITX sized 970, not  a 980 or something). Am I correct in understanding that I do not need to make any changes to the Akitio to increase the power limit of its PCI slot? It runs fine using the original adapter, but that adapter is not designed to handle much more than 25 Watts, right? 

 

Are there siginificant risks if using Akitio adapter + PSU for a longer time? I am really stuck here....Thanks for the help.

Edited by ptrs2016
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  • 5 weeks later...

@Dschijn Seems you were right about the PSU. I switched to using a Dell DA-2 and - after plugging it directly into the wall - it seems to run stable now. Odd: a 220W Dell adapter beating both the 450W and 550W PSUs!

 

Also peculiar and noteworthy that the DA-2 needed to go directly into the wall socket and couldn't go into splitter.

 

Thanks again for the help! 

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  • 1 month later...

Hello I am new to the Akitio world, I am going to install a Inno3D 1070 to the box, as I read from the spec, 1070 draws 150W from the PSU, while it's having a 8-pin molex connector which supplies 150W to the GPU, do I need to create the Molex to barrel plug or use a powered riser for the PCIe connection? Thanks everyone.

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I am powering my akitio TB2 using 2 molex to barrel plug from a 620W ATX PSU with GTX 1070 inside, but I am getting error 43 in windows, would it be a power issue? do I still need to use a powered pcie riser?

Edited by CodeSix
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  • 1 month later...

@Dschijn

May I ask your advice about my wrong-doings regarding the molex to barrel adapter?

 

I connected the PSU, Akitio and GPU together (no Thunderbolt or DisplayPort yet) and started up the PSU for the first time. After maybe 10-15 seconds, I could see slight smoke and smelled something burning so I shut the PSU down immediately. Turned out that the adapter's two yellow cables were quite hot and insulation (not the metal inside) somewhat melded together near the barrel terminal (see picture). The leftover black cables were hot as well but didn't meld and seem to be undamaged. I visually checked both Akitio and GPU afterwards - they seem to be fine for now. Tried powering Akitio with the shipped power supply - seems fine.

 

When making the adapter, I followed a post from this thread . The adapter consists of 6-pin to 2x molex adapter, 6-pin male/female extender cable and the barrel terminal (overview here). Despite amazon's pictures, the 6-pin to molex cable came with black cables instead of the red ones. I connected the 6-pin end to one of the SATA/PERIF slots on my PSU.

 

I'm a little scared of experimenting on my own now and would like to ask for help in pointing out any mistakes. Did I mix up the wrong black cables together (as I mentioned, there were two more) or is the cable's quality just that bad? How would you personally proceed or what replacement would you recommend (the overall power cable needs to be a little over 30cm)?

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@Dschijn

Ah, sorry about confusion :). I quickly put together an image that sums up what I did - let's use it as a base for further comments and a reference to individual pins. Real view of everything between Akitio and PSU is here. Additional info: the top-center pin of "A" is unused and attached to two more black cables.

 

I don't see where I went wrong, unless the PSU's connector doesn't match layout of "A" or unless I put the wrong black cables into the barrel terminal.

 

UPDATE: judging by the included PSU cables labeled "SATA" (6-pin to SATA) and "PERIF" (6-pin to molex), pinout of "A" is expected to look like this (as I connected my adapter to one of the "SATA/PERIF" slots on my PSU). I haven't been able to deduce the top-right pin's character yet - have to get a voltmeter first. If it's not ground, I guess the culprit is clear. If it's ground, I'm back to square one... In that case, is it okay to convert one of the SATA cables into the adapter for Akitio? More specifically, combine 12V (yellow) and 5V (red) cables into the positive slot of the barrel terminal? If my nooby calculations are correct, they should supply 85W, which means that if the GPU somehow prefers to draw power from the board when under stress (up to 75W), there might not be enough for the board itself?

Edited by ti_padawan
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@ti_padawan

Do not use Molex or SATA pins from the PSU. Your approach to use the 6-pin PCIe was good. It doesn't really matter what the pinout on the PSU itself is, as long as you use the original cable to get a male 6-pin at some end and can rely on that standardized pinout.

Why does your drawing have Molex coming out of the 6-pin?

 

Did you apply the paperclip trick to power on the PSU? Do NOT power on the PSU without any consumer. At least have a fan connected.

 

Why did you connect a 6-pin to SATA? on the PSU side? That might have been the problem... SATA pinout is not ground and 12V.

Edited by Dschijn
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@Dschijn

 

1 hour ago, Dschijn said:

1. Why does your drawing have Molex coming out of the 6-pin?

2. Did you apply the paperclip trick to power on the PSU?

3. Why did you connect a 6-pin to SATA on the PSU side? That might have been the problem... SATA pinout is not ground and 12V.

 

1. Just to mark the original cable (6-pin to 2x molex) that I converted into 6-pin to barrel terminal - that's why the connection is crossed. But I guess I could have left that out... my apologies :).

2. Yes, sort of - the PSU came with a tester that I attached to the motherboard cable :).

3. Because the only 6-pins on the PSU are labeled "SATA/PERIF". If all else fails, I could use one of the 8-pin VGA slots (there are two) to power Akitio after converting the appropriate shipped cable into an adapter (like you said). But I wanted to avoid that and keep the cables intact as I might go into a SLI setup eventually (and I wanted to use both slots for my GPU). The only remaining option is the 8-pin labeled CPU. Hmm, judging by this, I could create an adapter for Akitio from the 8-pin to 4-pin cable (exactly 2x 12V and 2x ground)? Luckily, there is still another 8-pin to 8-or-4-pin cable CPU cable included :).

 

Quote

1. Do not use Molex or SATA pins from the PSU. Your approach to use the 6-pin PCIe was good.

2. It doesn't really matter what the pinout on the PSU itself is, as long as you use the original cable to get a male 6-pin at some end and can rely on that standardized pinout.

3. Do NOT power on the PSU without any consumer. At least have a fan connected.

 

1. Okay, thank you :). Right now, I'm not using them though, unless you meant the "SATA/PERIF" 6-pin slots as a whole?

2. Yes, I figured that out yesterday (one always learns something new).

3. A very good advice, thank you :). Despite I did that one or two times since I got the PSU, let's hope nothing happened :).

 

UPDATE:

Forgot to mention that all the included "SATA/PERIF" cables end with either SATA or MOLEX so I shouldn't use them (e.g. "Do not use Molex or SATA pins from the PSU")?

Edited by ti_padawan
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