Black screen - replaced everything but PSU and HDD

[mrtraver]

PC started showing just a black screen. The GPU fan was not running, so I thought "dead GPU". I tried a different GPU that was working when I pulled it from another PC, and still just a black screen. Now I was thinking "dead motherboard". It is too old to consider replacing, but I did have enough working parts lying around to frankenstein a different build. The only thing I am still using is the HDD (with the Windows installation) and the PSU, and I still have a black screen. I know the monitor and cable are OK; they are the ones I am using as I type this on my main PC.

Can a PSU or HDD cause a totally black screen? Not even a POST screen appears, but I don't get any error beeps from the motherboard. I don't have any spare PSUs or HDDs lying around to test, so I may have to pull from an existing PC in the house.

Any suggestions??

Thanks!

 

[Cycloid Torus]

"Can a PSU or HDD cause a totally black screen?" I would say YES to that.
Take a look at https://www.computerhope.com/issues/ch000607.htm

 

[mrtraver]

Thanks! Turns out it was the power supply. I had never thought a failed PSU could cause that - the only one I had fail before did not do ANYTHING when I tried to power on the PC.

FYI, both my failed PSUs are no longer made - they were both OCZ brand. One lasted about 12 years, and this one was about 7 years old when it failed.