I have a mid-2010 quad-core 2.8 which has been running Mojave since it released. I upgraded to a flashed Radeon 7950 at that time. It ran without issues until sometime in 2020 when it started failing to boot. It sometimes would not turn back on after being shut down - the fans would spin up, power LED was on, diagnostic LEDs not indicating any problems. It would take a combination of just leaving it and waiting, zapping the PRAM (do people still call it 'zapping'?), resetting the SMC or pulling the video card and resetting the RTC to get it to boot up.
Pulling components did not get it to boot up either, even with all PCI cards and drives removed.
Once finally booted it would behave normally, until I needed to shut it down once more. I bought a spare backplane board as the symptoms seemed to point toward it being the culprit.
I finally got around to looking into a post-Mojave OS update and went through the process of building an installer with the OCLP. This posed some issues - such as not being able to restart reliably and not being able to see boot screens (but that's a card-related problem). I swapped the backplane board out after dealing with the issue for another year. It took some persuasion to get it to start up the first time - it was stuck in a reset loop but reseeting the SMC and then PRAM got it booted.
Since the backplane board didn't correct the issue, I began to suspect the power supply as it was still the factory unit which was now 13 years old and spent most of that time powered on. Bought a 'tested, pulled from working machine' power supply for $30-ish. No change in behavior.
Out of desperation I pulled the factory non-Metal compatible Radeon card back out and installed it. It booted up fine - but no video. I could log in via remote desktop to verify it was working. It will also boot with no graphics card installed. This made me suspect the Radeon 7950 I had been using since Metal compatibility became a requirement. I just received a Radeon R9 208X which purported to show startup screens which my 7950 never had. After resetting the PRAM it started up normally and did indeed show boot screens.
It's currently running but it was stuck in the loop of failing to boot when I restarted in an attempt to boot from the USB OCLP drive. Removing the graphics card and having none installed allowed it to boot. Otherwise the power LED comes on, the fans spin up and it does nothing further. In these situations a short press on the power button will turn it off - it does not require holding the button as when it is booted.
I’ve tested the RAM one stick at a time in each of the slots with no change in behavior with any combination.
Since it will boot every time with no graphics card installed - I suspected a power issue. I grabbed a couple old PSU’s and jumpers to run without a board. I used those PCI-E connectors for the 280X (also tested with the 7950) but it still would not boot with the card installed and powered. If I left the external PSU off, the system would boot - but with graphics disabled.
Now that I'm through all the exposition, does anyone have any thoughts what I might try to remedy this issue? I'm not sure if it's worth pursuing Monterey on this machine or not, but I installed an Accelsior S card as the intended target drive for it.
Pulling components did not get it to boot up either, even with all PCI cards and drives removed.
Once finally booted it would behave normally, until I needed to shut it down once more. I bought a spare backplane board as the symptoms seemed to point toward it being the culprit.
I finally got around to looking into a post-Mojave OS update and went through the process of building an installer with the OCLP. This posed some issues - such as not being able to restart reliably and not being able to see boot screens (but that's a card-related problem). I swapped the backplane board out after dealing with the issue for another year. It took some persuasion to get it to start up the first time - it was stuck in a reset loop but reseeting the SMC and then PRAM got it booted.
Since the backplane board didn't correct the issue, I began to suspect the power supply as it was still the factory unit which was now 13 years old and spent most of that time powered on. Bought a 'tested, pulled from working machine' power supply for $30-ish. No change in behavior.
Out of desperation I pulled the factory non-Metal compatible Radeon card back out and installed it. It booted up fine - but no video. I could log in via remote desktop to verify it was working. It will also boot with no graphics card installed. This made me suspect the Radeon 7950 I had been using since Metal compatibility became a requirement. I just received a Radeon R9 208X which purported to show startup screens which my 7950 never had. After resetting the PRAM it started up normally and did indeed show boot screens.
It's currently running but it was stuck in the loop of failing to boot when I restarted in an attempt to boot from the USB OCLP drive. Removing the graphics card and having none installed allowed it to boot. Otherwise the power LED comes on, the fans spin up and it does nothing further. In these situations a short press on the power button will turn it off - it does not require holding the button as when it is booted.
I’ve tested the RAM one stick at a time in each of the slots with no change in behavior with any combination.
Since it will boot every time with no graphics card installed - I suspected a power issue. I grabbed a couple old PSU’s and jumpers to run without a board. I used those PCI-E connectors for the 280X (also tested with the 7950) but it still would not boot with the card installed and powered. If I left the external PSU off, the system would boot - but with graphics disabled.
Now that I'm through all the exposition, does anyone have any thoughts what I might try to remedy this issue? I'm not sure if it's worth pursuing Monterey on this machine or not, but I installed an Accelsior S card as the intended target drive for it.