Dell DA-2 adapter switches off/loses power when gpu is connected
 
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Dell DA-2 adapter switches off/loses power when gpu is connected  

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ugpu_igpu_wegpu
(@ugpu_igpu_wegpu)
Active Member
Joined: 1 year ago
 

Hello all,

I accidentally posted this under the wrong forum  (thunderbolt - PSU) previously https://egpu.io/forums/postid/83354/ . Posting it here as it might be more appropriate

After trying for a few days, I have been unable to get my eGPU setup working. When I have it connected as I think it should be, the Dell DA-2 power seems to switch off but otherwise it seems to be working fine. I am not sure if it is a Dell DA-2 problem but I was hoping I could get some help on this from the community. I have included all details I thought were relevant in order to give the most complete picture so I apologize if the post seems a little long

I bought the following components with the aim of having an eGPU setup to work with my Lenovo T420.

  1. A Dell DA-2 220W adapter
  2. EXP GDC Beast 8.5c enclosure (expresscard)
  3. EVGA GTX 970 FTW GPU (used) that needs two 6 pin power connectors
  4. 6pin male to 6pin male PCIe cable
  5. two 6 pin PCIe power splitters - 6 pin female to two 6 pin male PCIe power splitter

My plan (based on other working builds and research I had done prior to purchase) was to use the Dell DA-2 to power the EXP GDC Beast . Then connect the 6 pin output from the EXP GDC and connect it to the two 6 pin power connectors on the GPU.

Following are the things I tried and the behavior I observed

  • I connect the dell da-2 adapter to the exp gdc and have the gpu in the pcie slot without any additional cables connected. when I switch on my laptop I see the green light on the adapter and the exp gdc green light. The fans on the GPU switch on and then turn off(its more like a twitch) constantly. If I remove my expresscard and then reconnect it, the fans run at (what I think is) full speed. During this time, the GPU is never detected by the OS (neither windows 7 nor linux). Since the power connectors for the GPU are not connected, I thought it makes sense that it's not working
  • There are 2 6pin slots on the GPU - slot #1 and slot #2. If I now connect the "6 pin male-6pin male" cable from the exp gdc beast output to slot #2. I observe the exact same behavior as before - fans start spinning at full speed or repeated twitch and turn off
  • However, as soon as I connect the 6 pin output from the exp gdc into slot  #1 using the "6pin male-6pin male", the dell DA-2 powers off (green led switches off), exp gdc powers down.
  • I tried connecting the 6 pin output from exp gdc to both the slots via connecting "6pin male-6pin male" cable to the "6pin female to two 6pin male cables" and observed the same behavior. Any time the 6pin output from the exp gdc is connected to slot #1 (irrespective of whether slot #2 is connected or not), the da-2 switches off. In addition, if I have this setup before powering on the adapter and then try to power it on, it doesn't power up (no green led on the adapter or light on the exp gdc )
  • I also tried all of this by following some of the recommendations here to have the PSU to be permanently on. I first tried with the ATX switch set to On on the exp gdc beast . I also tried the paperclip approach. When I tried these, I didn't need to turn on the laptop - I could observe the same behavior as soon as power was connected i.e. I repeated the same steps above without the laptop turned on and observed the same behavior

My understanding is that I need to have both the 6 pin power slots in my GPU connected in order for it to function properly. However, trying to do so seems to shut my PSU ( Dell DA-2 ) off. When slot #1 is not connected, the adapter does not switch off but the GPU doesn't get detected in my OSes and the GPU fans either constantly twitch and turn off or run at full speed depending on when the expresscard is connected.

Could someone help determine what I might be doing wrong or how I could go about trying to fix this ?

Thanks

To do: Create my signature with system and expected eGPU configuration information to give context to my posts. I have no builds.

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ugpu_igpu_wegpu
(@ugpu_igpu_wegpu)
Active Member
Joined: 1 year ago
 

Just wanted to give a small update here in case this makes things clearer.

I tried connecting the dell da-2 directly to the GPU via 6 pin PCIe power splitter i.e. "6 pin female to two 6 pin male" cables skipping the exp gdc beast completely i.e. the power brick to the gpu directly without connecting anything else. I observed the same behavior in this case as well. As soon as I connect a cable into slot #1, the Dell DA-2 switches off (or doesn't power on if it was already off).

Do you think there is something wrong with the way I'm connecting the cables to the GPU ?

image

For reference this img is what my GPU looks like. The slot #1 I'm referring to is the 6pin slot on the left. slot #2 is on the right.

 

To do: Create my signature with system and expected eGPU configuration information to give context to my posts. I have no builds.

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chasseur_de_mer
(@chasseur_de_mer)
Active Member
Joined: 1 year ago
 

@ugpu_igpu_wegpu

I've never used the DA-2 before so I have no idea about the DA-2 powering off that you mentioned.  However, my EXP setup is also an EVGA 970 SSC but with a regular 550 watt power supply, so I have some theories on what might be going on:

1. Below is a photo from the EXP manual (I think my version is 8.0, it wasn't indicated anywhere on the box or in the manual). It mentions something about a 150 watt maximum for the DC 12-volt in port.

EXP GDC Manual v2

 

2. Here is a video of a working setup with an EVGA 1060 3GB. It also shows a 6-pin male to 6-pin male PCIE cable from the EXP 6-pin side port to the supplementary power connection of the 1060, but note at the 0:41 mark that the 1060 only has one 6-pin supplementary power connection. We have two of those.

 

3. On some GPU database sites, the 1060 3GB used in the above video is rated at 120 watts TDP; while the 970 FTW is rated at 148 watts TDP. I checked some power calculator sites, and the power requirement for my 970 SSC was even estimated at 170 watts.

My theory is that the EXP's power limit, when using the side 6-pin port, is just around 120 watts.

Hope that helps.

2018 14" Lenovo IdeaPad 330-14IGM [7th,4C,P] + GTX 970 @ 4Gbps-M.2 (EXP GDC 8.x) + Win10 [build link]  

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ugpu_igpu_wegpu
(@ugpu_igpu_wegpu)
Active Member
Joined: 1 year ago
 

Thanks for your reply @chasseur

 

Posted by: @chasseur_de_mer

My theory is that the EXP's power limit, when using the side 6-pin port, is just around 120 watts.

That is quite possible but going into it I did check similar builds and found that people were able to use the dell da-2 +exp gdc with the 2 power slots in gtx 970 in builds such as this and this

Even if I don't use the the 2nd power slot and only use the first one. i.e. I only connect the the side 6 pin port to slot #1 directly, the power supply still switches off.

Further, if I eliminate exp gdc from the equation entirely and connect the dell da-2 directly into the 2 power slots on the gpu using a splitter cable, it exhibits the same behavior - Connecting the da-2 to slot #2 is no problem, the led on the da-2 stays green. Connecting to slot #1 switches off the the da-2 and doesn't turn back on until I remove the cable from slot #1.

Now, I'm wondering if it is the GPU itself that might be an issue. For eg: this old post here https://forums.evga.com/FindPost/2705345 talks about something like that. Contacting the previous owner though (ebay), they say they didn't face any such issues and it was working fully before shipping it to me.

I don't have another PSU to try it with, so wondering what would be the best way to figure this tou

 

To do: Create my signature with system and expected eGPU configuration information to give context to my posts. I have no builds.

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chasseur_de_mer
(@chasseur_de_mer)
Active Member
Joined: 1 year ago
 

Now that's informative, the DA-2 can feed more power-hungry GPUs.

I hope you could have a friend test your 970 just to make sure it's working.

If the 970 works, there might be something with adjusting the EXP and the laptop during initial setup. In the Lenovo build you mentioned, the EXP worked right from the start on Windows 10.

In my build, before connecting my laptop NGFF-HDMI cable to the EXP, I first had to get into BIOS and select "PXE boot to LAN - disabled", then I did a hard shutdown (long press on the power button). I connected the HDMI cable to the EXP, and the laptop started to boot but froze on the Lenovo splash screen, so I did another hard shutdown. I switched the laptop on again, booting was slow but I was able to get into Windows 10 and install the EVGA driver.

2018 14" Lenovo IdeaPad 330-14IGM [7th,4C,P] + GTX 970 @ 4Gbps-M.2 (EXP GDC 8.x) + Win10 [build link]  

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ugpu_igpu_wegpu
(@ugpu_igpu_wegpu)
Active Member
Joined: 1 year ago
 

@chasseur_de_mer, thanks for the help.

It turns out that the problem was indeed the GPU and not the power supply. Although I couldn't test that GPU on another machine, I was able to try out a different power supply and it presented the same problems. I explained the issue to the seller of the GPU and they, thankfully, offered a refund for it.

I subsequently bought a different GPU and tested it on the EXP + dell da-2 and it seems to be working fine

 

To do: Create my signature with system and expected eGPU configuration information to give context to my posts. I have no builds.

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chasseur_de_mer
(@chasseur_de_mer)
Active Member
Joined: 1 year ago
 

You're welcome and all the best to your EGPU project!

2018 14" Lenovo IdeaPad 330-14IGM [7th,4C,P] + GTX 970 @ 4Gbps-M.2 (EXP GDC 8.x) + Win10 [build link]  

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