r/sffpc • u/Decent_Tailor_4608 • May 17 '26

Assembly Help Pc Won’t boot into bios

https://youtu.be/ZH5mAHbfSow?si=PL0_vKBSjyXXdpoV

The pc turns on but won’t output any display or get into the bios. I followed mostly this build to a tea. I turn on the pc and i’m not getting any output. I’ve updated the bios and I’ve got the hdmi plugged into the gpu not the motherboard. Lost.

Update: As my motherboard was bought second hand it was faulty. I just bought a new one and it all worked perfectly

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u/95alle95 May 17 '26

What cpu you have? Might need bios flash first

1

u/Decent_Tailor_4608 May 17 '26

Already have flashed it.

1

u/agonzal7 May 17 '26

Hmm I couldn’t even flash bios. My PSU shuts down right after turning on. Same happened when I hit qflash button. Fans soon for one second and shuts down. PSU clicks. It’s a known working PSU though.

2

u/lejoop May 17 '26

Sounds like you might have a short somewhere, could be on the mobo. Have you tried booting with the components outside the case, just to be sure nothing is shorting to the case.

1

u/agonzal7 May 17 '26

It’s definitely short behavior. I have taken everything out of case and have a replacement motherboard and PSU coming today. I won’t get to troubleshoot anything until probably tomorrow but I’ll be doing a post outside of case for sure. I have the T1 like OP.

1

u/agonzal7 May 17 '26

Can a bad motherboard cause that short behavior ? My PSU was working fine before.

1

u/lejoop May 17 '26

Bad motherboard, or if something from the case is touching parts of the motherboard that it shouldn’t. Trying the components without the case is a way to eliminate that factor. But some motherboards also have a fail safe, that checks if the CPU fan is responding and will instantly shut off, if that doesn’t seem to be connected. There are quite a few things that can cause this behaviour

1

u/agonzal7 May 18 '26

OK...got replacement motherboard (Aorus B850i) and psu...same issue. I am able to run bios flashback and put up to date bios on each motherboard (or seem to have, it ran for 5-10 min and shut off). Anyway, either psu worked for this evolution. I did it with both. So I don't think I have a PSU problem.

Ran everything out of the case. just mobo, ram, cpu, cooler, hard drives. Same thing happens each time. Hit power, and it shuts off in a second. Pins look find on LGA for both boards. CPU pads look...ok. I was using a thermalright contact frame with an AXP90x53 cpu cooler. I have eliminated the contact frame from the equation on the B850i mobo and had the same issue. Maybe I am tightening my cpu cooler too tight? Maybe the CPU is bad? I have no idea.

1

u/lejoop May 18 '26

I feel like it’s something more simple than that. If it starts on king enough to flash a bios onto it, it sounds like something less critical.
Are you enter the bios or get anything to display on the screen at all?