HP 8300 with Radeon HD 5850 fans spin, then stop

[Mighty]

My secondary computer (chat, light surfing, was my gaming machine 8 years ago) died and I bought a refurbished HP 8300 tower to replace it. I like running SETI@Home, so I wanted to pull the GPU from the dead machine. When I bought this machine I didn't realize it had a wonky motherboard. But, I found threads on here and YouTube videos describing how to upgrade the PSU. I got an EVGA 500W.

I'm seeing intermittent issues with this machine since I cobbled it together. Mostly, it has worked for about a month. Twice it has refused to boot.

First time was a week or two after I got it up and running. One morning, I walked in and it was powered down. Pressing the power button, the fans just spun for a few seconds, then stopped. This motherboard has no POST LED codes, so I have no idea what is causing it to abort. No beeps.

I pulled all of my upgrades and I plugged in the stock power supply. It booted fine with the onboard video. I swapped back to the new power supply and reinstalled the GPU. It booted.

It behaved again for a coupla weeks. I think I rebooted it for various normal reasons a few times in that stretch.

Tonight, while I was using it, the screen cut to black and the machine shut down. Pressing the power button just spun the fans for a few seconds.

This time, I left the new PSU connected and pulled just the GPU. It booted. I reinstalled the GPU. it won't boot. The green LED on the motherboard is lit.

I don't have a system at hand where it's convenient to try the GPU. I suppose I could do that if that's the only thing we can come up with.

I just pulled and reseated the RAM. Then, I tried with one pair of RAM sticks, then the other. No change.

Does anyone have any other ideas besides the GPU choosing to slowly go bad?

Is there any way to find out what the motherboard thinks is wrong during POST?

 

[Lutfij]

Prebuilt systems that aren't meant to be tinkered with by the end user are horrible systems to diagnose and troubleshoot. Which form factor do you have? Are you on the latest BIOS update for your motherboard? Seeing how the GPU is the component that pulls the most power from your system, I'd say that the PSU can't deliver the power necessary for the entire system.

 

[Mighty]

Prebuilt systems that aren't meant to be tinkered with by the end user are horrible systems to diagnose and troubleshoot. Which form factor do you have? Are you on the latest BIOS update for your motherboard? Seeing how the GPU is the component that pulls the most power from your system, I'd say that the PSU can't deliver the power necessary for the entire system.

The stock PSU was definitely under powered. And, it lacked the power connectors I needed. The EVGA 500W that I got to replace it should be plenty. In fact, one of the YouTube videos had almost precisely the same GPU and PSU.

And, again, it was working for about a month. Except for that one glitch, I was having no issues, even though it was running SETI@Home 24/7.

Also, the first coupla seconds of boot does not push the GPU into eating a bunch of power. This is not an insufficient power issue. Something else is tripping up the POST.

 

[Mighty]

I ended up punting and installed a much lesser card that I had lying around. (I needed a card, because I run two monitors on this system.)

So far, the new card is working fine. That suggests that the problem is the beefier Radeon. Maybe someday I'll set aside time and rip my other machine apart in order to test it.

Let's hope that the much lower computing power doesn't result in us missing spotting ET