Question Possibly broken GPU, problems with rest of system, help

[schwwwk]

Built a PC a few days ago. Worked fine save for a few issues:

• I was having resolution issues with the monitor. If I connect it to my laptop via VGA it works fine, but if I connected it to the gpu (GTX 970) using HDMI and set it to native resolution the image would be too large for the screen, and I'd have to set it to a lower resolution just to see everything. It worked fine on a different (larger) monitor.
• An old case fan wasn't able to be powered via the motherboard header - I still don't know the root of this problem unfortunately. I have another thread on this.
• I have a dualboot system (Windows and Xubuntu) but for some reason the grub menu isn't showing up - I have to go into bios to set the boot partition manually.

I was trying to resolve these first two problems when the GPU seemed to suddenly stop working.
I tried plugging the fan into the mobo header, pins aligned right (I believe), and set the bios to run it in 3-pin mode. Fan didn't work but I did notice a burning plastic smell near the header/gpu when I went to turn it off.
I gave up on trying to get the fan to work for the meantime and booted it up to tackle the resolution issue, which was basically just messing with overscan settings in the Nvidia control panel. I rebooted and got a black screen - no BIOS or OS.

This is where I'm at now. No image from the 970 whatsoever.

Replacing it with an older GPU shows the BIOS and allows me to boot into Windows 10. The resolution is still screwed, I don't know if this is just because it's an ancient GPU (GTS 250). Booting into Xubuntu gives a black screen but with backlighting. I tried booting into it off an installation USB and had to change USB ports and use safe graphics mode for it to work.

I've tried jumping the CMOS. The 970 is definitely placed firmly into the PCIE slot, and the 8-pin power is connected. My main concern is the GPU is dead but this doesn't seem to be the only issue. At the moment it's like half of my pc is malfunctioning - I do not feel very lucky. Would appreciate some help.

My parts are as follows:
Ryzen 5 1400
Silverstone Essential ET550-G
Gigabyte B450M S2H V2
Asus GTX 970
Samsung 860 Evo 500gb
Corsair Vengeance LPX 16gb
Thermaltake Armour+ MX

 

[schwwwk]

An update.

I went through a more systematic process of making one change to the system, testing out one thing, and writing the result down before moving onto the next thing.

I realised that I didn't plug in the psu power for the GTS 250 - the power connector faces the side so I didn't notice it and assumed it was powered by the slot only. Once I plugged this in things went a lot better. I was able to boot into Xubuntu off a usb normally - this gave the correct resolution as well. After a reinstall of Xubuntu, the grub menu shows up on boot and the resolution is fine. The usb ports seem fine now too.

My guess is that the GTS is somehow able to operate without 6-pin power in some situations (bios screen, booting into Windows 10, Xubuntu with safe graphics enabled) but fails in others. Curious. I think my initial installation of Xubuntu went wrong as well, there were a few things that were different then.

At this point all my weirder computer issues are solved, with the only things not working are the GTX 970 and the case fan.

I tried running the case fan with the GTS in case the psu was faulty and the 970 + the fan was asking too much of it (unlikely but I figured I'd give it a shot). Still no sign of life.

The 970 appears to be receiving some power - there's a little led that shines whenever it's connected to the psu, even if the pc is turned off. I also noticed that immediately after turning the pc on, the 970's fans spin for a bit, but then stop. The fans aren't supposed to run unless if they're under load so I believe this is normal. I'm just not getting a display at all. The monitor doesn't give a "no signal" sign, the led on it is just orange instead of blue.

I noticed that the pcie connectors on the 970 have these kind of white spots on them - the connectors on the GTS look much cleaner. I don't know if this is a significant thing or if trying to clean it would help anything.

It's not super relevant but I ran Windows 10's memory test and I got no errors.

At this point I'm thinking the 970 is broken. I don't have a second system I can test it in unfortunately. Would replacing it be my only option, or are there other things I should try beforehand?

 

[schwwwk]

Another update.

I tried plugging another monitor into the pc with the gtx 970 installed. I wasn't expecting anything to work but surprisingly enough, it booted up fine! So the main culprit here is probably my monitor, not my gpu, or any other part of my system.. thank god.

Then I tried connecting it to my initial monitor and again it works. I don't know why - I had a vga cable plugged into the monitor (but not anything else) I plugged out but that's the only change. I went through a few iterations of plugging in and plugging out cables to the monitor when things initially broke too. So I don't know what caused it to go from broken to working again.

This is bizzare though. This monitor has always worked fine when connected to my old laptop via vga. It worked mostly fine using the hdmi port when it was connected to the 970, save the resolution issues. Only when I started screwing around with Nvidia monitor settings (which aren't relevant anymore, as I reinstalled Xubuntu) did it black out completely. And now it's working again for no explicit reason?!

I'm just happy it works right now. The resolution is still stuffed - at "normal" resolution the image is still too big for the screen - which brings me back to square one I guess. But at least the gpu isn't broken.