A user has shared pictures of a burned 12V-2×6 cable, surprisingly connected to a 250W Nvidia GeForce RTX 5070 that was originally thought to be safe from power connector issues. We’ve yet to determine the cause, but evidence points towards a short circuit on the header’s side this time around rather than the port.
Smoke coming out of a brand-new PC is pretty much any system builder’s worst fear, but that’s exactly what happened to X user Ere9w just two seconds after turning their rig on. Despite checking all cables several times after hearing about several melting incidents, they too weren’t safe, marking the first time we’ve heard of an RTX 5070 being caught in the mix.
Looking at the shared picture, we can notice a couple of unusual points. First, the molten cable wasn’t one of the 12 carrying 12V plus ground. Instead, it was one of the sense pins used to communicate with the PSU about the power it can send. These wires shouldn’t carry anywhere near enough current to cause melting, which hints at a manufacturing defect or damage that caused a short circuit with a 12V line.
Secondly, the 12V-2×6 header on the graphics card looks damaged as the third pin on the bottom row seems missing. In the following video posted by @ere9w, we can see that the pin wasn’t missing but instead got pushed inside the header. While this could be a simple manufacturing defect, unfortunately, evidence points to a user error.
It seems that during the cable installation, the pin holes weren’t perfectly aligned, causing one of the sockets to push the pin back without making a proper connection. Thus, as pointed out by @unikoshardware, we can speculate that this pin went back enough to contact a sense pin, causing a short which sent a lot of power through this thin wire, melting it. Also, note that while these cables look like modded ones, they are in fact the original bundled with Seasonic’s Focus GX 750 PSU.
Regardless, this shouldn’t happen to begin with. The header should be resistant enough to give feedback when pushed incorrectly as you’d get with a traditional eight pin. If the delicate PWM fan and ARGB headers on your motherboard can handle it, so too should larger GPU power cables. Perhaps a header with some plastic separation between the 12V, ground, and sense connections would be a good start.
What is sure is that Ere9w will have a hard time convincing Zotac that their Nvidia GeForce RTX 5070 came defective from the factory. We hope neither the card nor the PSU have suffered from any irreparable damage. With some luck, the built-in protections did their job correctly, and the user only needs to re-seat the problematic pin back into place. They may even be able to reuse the same cable after covering it with a protective sleeve.
