GPU Zotac GTX 1080Ti Founders [Repair] - Page 1
Forum section: electronics / repair

author: MilanBibock
author_rank: Newbie
timestamp: April 30, 2019, 10:28:40 am
content: Hi, I've a GPU that is not working. I've plugged into 2 different PC, but the fan is spinning but no video.I can find the GPU in the device manager, but with code (43).I've contact Zotac Support and he has told me that there is probably a power supply problem.So I've decided to check the PCB, but I can't find online the location of the test points for 12v, 5v and 3.3v to start the troubleshooting.Anyone can help me to troubleshoot this PCB?THANKS

author: anewmanx
author_rank: Contributor
timestamp: May 01, 2019, 03:21:20 am
content: Have you thought about passing a current limited (1ma or less) voltage to the pci-e connector rails one at a time and tracing where it goes and where it stops? I know nothing about those cards so that’s my best advice. Alternatively you could put 100% alcohol on various chips and turn the card on to see if one of them is getting super hot. I’d check the capacitors if you can before anything else.

author: jc101
author_rank: Frequent Contributor
timestamp: May 01, 2019, 09:37:20 am
content: Silly question, but you have also connected the external power connector on the card too? From memory these need to be connected for the core to get up and running.

author: mariush
author_rank: Super Contributor
timestamp: May 01, 2019, 10:51:31 am
content: My suggestion :First of all check the small fuses on the video card, if one is open then you know that area has problem.The card will take 12v from the pci-e slot and will take 12v from the extra pci-e 8pin power connectors... there's gonna be fuses for each.The board has a vrm with multiple phases and it's quite possible that a few phases re powered from the pci-e slot, and the rest from the pci-e 8pin connectors - for example there may be a 8 phase vrm, and you have 2 phases powered from slot and 6 phases from pci-e 8 pin connectors.I would suggest using a pci-e riser adapter like these:https://www.amazon.com/dp/B075ZSDD4H/I don't mean exactly that one, there's others on eBay for much cheaper --- you just want one that takes in only 12v and has 3.3v regulator on the board with pci-e x16 slot - this way there's no power coming in from the PC, all the power is from the 12v cable.So, you can connect the 12v input and use some pci-e 8pin cables to power the whole video card with 12v, and you can limit the current going to video card to something like 1A ... this would allow you to safely start the video card with no heatsink on it (maybe just a small heatsink on the gpu chip alone) and you can use your finger or some isopropyl alcohol drops to see which mosfets or regulators or ceramic capacitors heat up significantly - that could indicate a short.If the mosfets in the VRM or memory regulator don't heat up, it could be they're not even starting because the controller is dead or a fuse is dead so electricity doesn't even reach that circuit.0.5A or 1A should be fairly safe, as long as you pay attention ... a video card board is thick enough that a shorted mosfet will dissipate 10w or so easily into the board so it will last for a few seconds until you spot the burning hot chip

author: wraper
author_rank: Unknown
timestamp: May 01, 2019, 10:56:54 am
content: Check resistance on RAM power rail. Should be over 100 Ohm. Also check voltage on this rail if resistance is fine. Symptoms sound like problem with RAM. You can measure it across the caps in red box. You can safely power up this card without any heatsink for a few tens of seconds if not booting (disconnect boot drive).

author: MilanBibock
author_rank: Newbie
timestamp: May 04, 2019, 12:11:50 pm
content: Hi, Wraper and thanks for your reply.I've checked and the resistance between GND and + of the caps is 84.8 Ohm. I've checked the voltage and on the positive of the caps there is 1.38V. The 2 caps are in parallel right?? becasue both - are grounded.Thanks

author: MilanBibock
author_rank: Newbie
timestamp: May 04, 2019, 12:19:07 pm
content: I've also analyzed the GPU with GPU-Z:

author: wraper
author_rank: Unknown
timestamp: May 04, 2019, 12:19:58 pm
content: Quote from: MilanBibock on May 04, 2019, 12:11:50 pmThen I guess either one of the RAM chips, GPU, or BGA soldering is faulty. If you have ability to at least solder RAM, I'll upload somewhere Nvidia tool for GPU RAM testing (boot flash drive image). Otherwise consider this card irreparable and sell it on ebay (or to me if you can offer reasonable price).

author: MilanBibock
author_rank: Newbie
timestamp: May 04, 2019, 12:57:23 pm
content: And wich is the reasonable price?

author: wraper
author_rank: Unknown
timestamp: May 04, 2019, 01:03:12 pm
content: EUR 150 including shipping to Latvia, paypal.