Mining Rig BBQ

[DevonNelson]

I have a mining rig running in a Rosewill 4U case with 7x GTX 970's (room for 8 cards total), I have an 850w PSU, and a 1000w PSU. I am using an Add2PSU relay to turn the 1000w PSU on. I am powering all of the PCIe risers with the 1000w, and I split up PCIe power between the two PSU's. 
 

I built this rig a few months back with 3 GTX 970's, and 1 PSU, and I recently added the rest. I spent 32 hours straight fighting with drivers trying to get the machine to work. I got fed up, bought an SSD, and reinstalled Windows.

 

I got all 6 cards working in nicehash, and all was good. I went to put the lid back on the case and I immediately could smell something cooking. I looked inside the case, and I could see one of my GPU's working on starting on fire. I shut the PSU off, and the second I did, it went out. 

 

Obviously something is being shorted when I try to put the lid on. But I cannot find a cause. I have inspected all the wiring that can come in contact with the lid or case, and I see no problems with any insulation. I cant find any wires being pinched, or anything. At this point, I just need advice on where to go from here. Currently I have a $2000 fire hazard...

[8uhbbhu8]

Maybe don't run with the lid on? It will help with airflow as well as these cards will need it when mining. If you can see that the gpu is having an issue I'd say it's a faulty riser, power plug/cable itself. What psu do you have?

[DevonNelson]

17 hours ago, 8uhbbhu8 said:

Maybe don't run with the lid on? It will help with airflow as well as these cards will need it when mining. If you can see that the gpu is having an issue I'd say it's a faulty riser, power plug/cable itself. What psu do you have?

Its running in a rack and the lid has to be closed when I am not working on it. All the cards in the rig work and run just fine until I try to close the lid, at which point the only symptom I notice is spontaneous combustion. I have an 850w EVGA 80+ Gold, and a 1000W Rosewill 80+ Bronze, both are modular. The card that started to fry was hooked entirely into the EVGA psu. Logic would lead me to assume that a cable is being pinched/shorted when I try to close the lid. While the lid is solid up against the power plugs on the cards when closed, the one that shorted was possibly not even making contact yet due to where I was at in the process of closing the case. 

 

I inspected everything at the time, and I did not find anything. But that was 3am and I hadn't slept in 4 days, so I am going to go double check everything (again) and see if I find anything that looks to be a root cause.

[DevonNelson]

So update time:

 

The graphics card was on fire. There is fire damage to the cooler, and the riser is slightly scorched. 

 

annnnd.......: They both still work

 

I am guessing the short was caused by a PCI power connector. The 12V pins on those connectors are facing towards the lid, and exposed wire there could definitely be a cause. Im off to get food, then grab my multimeter. Time to see if there are any shorts there.