MP 1,1-5,1 5,1 Won't Boot - All LEDs Green

[Derived]

As part of my quest to get my 7,1 to run Linux (seemingly impossible at this point) - I decided it would be a good idea to pop my OWC 4M2 into my 5,1 to see if I could install Linux onto one of those drives and then install it back into the 7,1. The 5,1 is running a fully up to date version of Mojave and the latest firmware, for what it's worth.

I shut down the 5,1 which has been running almost nonstop without issue for nearly a year, pulled the side panel off, popped the 4M2 into my last open PCI slot (Others are occupied by a Sonnet USB 3.0 card, my SATA SSD boot drive on a PCI sled, and a Vega 64), and then buttoned it back up again.

Upon powering it back up, it refused to boot all the way, no chime, no video output. I assumed it was freaking out due to the 4M2 for some reason, and shut the machine down, pulled it out, blew some of the dust out while I was in there, and put it back together + turned it on again.

To my surprise, still no change. Still no chime and no video output. No blinking LEDs and the fans were acting normally, but it would not finish the boot. I tried the SMC reset, no change. Shut it down, pulled the power cord and let it sit like that for 2 straight days. Still no change. Pulled it apart, cleaned it thoroughly, inspected the CPU tray + all memory modules, pulled the USB card (as well as all 4 of the HDDs I have installed) and tried booting again. No change. Did the SMC reset a few more times. Pulled the NVRAM battery. Did the pushbutton reset. Still no change.

One thing I did notice is that the "GPU OK" LED did not light up with the Vega 64 installed. I don't remember how it behaved in the past but just to really be thorough, I dug up my GT120, popped it in...still no change. Although the GPU OK status light is green now.

I am at a loss at this point. I didn't bump or damage anything on the system board, and at least at first I didn't do anything other than simply slot the 4M2 into the top PCI slot. I have had the machine in this state before, but an SMC reset usually solves it. There are no other status LEDs lit up or flashing, fans still acting normally, power LED is steady on without flashing. System isn't beeping on startup either.

One thing to note is that I did break the top contact on the battery tray (not sure how, I applied very little pressure) when I tried swapping the battery as a last resort. I can't imagine that would be causing any issue as the machine doesn't need the battery to run. However I notice now that the machine powers on as soon as I plug in the power cord now. Haven't noticed that before.

Sorry for the book, just wanted to be thorough. I am at a loss as to what to try next. Unfortunately neither of my other 2 Macs will run Mojave and I can't run anything past Mojave on this machine, so being extra sure and trying to boot from this drive on another machine is a no-go. However it had no issues before that first shutdown so I don't suspect any issues there.

Thanks in advance.

 

[tsialex]

GPU_OK LED only works for AppleOEM GPUs. Are you sure that EFI_DONE LED is lit?

RTC battery being disconnected/not present makes the Mac Pro enter firmware fail-safe mode and power on when you connect it to mains power, anything that is RTC and NVRAM related will not work or work incorrectly, like BT and Wi-Fi. Not all macOS releases work correctly with the fail-safe mode, like no unsupported macOS release. Mavericks is my go to for this type of diagnostics.

I'd remove all disks, all PCIe cards, all DIMMs but one, install only the GT120 and a disk with Mavericks. If you can boot it, you will probably only need to repair the battery holder.

If you can't boot it, get a replacement backplane, unless you want to thinker with the backplane, replacing the SMD SPI flash memory and etc.

 

[Derived]

EFI DONE is lit as well, it's been lighting up this entire time in fact, that was my first thought.

I was worried that might be the case with the battery...I had perhaps misunderstood a few posts around the web I saw indicating the machine should boot and run without it, but based on what you're saying it sounds like that's not the case.

I am not quite sure if I can repair, might have to source a new backplane. It's a clean break, the top tab snapped off cleanly and with very little pressure, I was very surprised by this. Might try to solder it back together but my skills are rusty. Wonder if nearly 15 years of heat cycling caused it to be more brittle than expected.

Good thing these machines are now ancient and parts are a lot cheaper than they used to be...

 

[tsialex]

EFI DONE is lit as well, it's been lighting up this entire time in fact, that was my first thought.

I was worried that might be the case with the battery...I had perhaps misunderstood a few posts around the web I saw indicating the machine should boot and run without it, but based on what you're saying it sounds like that's not the case.

I am not quite sure if I can repair, might have to source a new backplane. It's a clean break, the top tab snapped off cleanly and with very little pressure, I was very surprised by this. Might try to solder it back together but my skills are rusty. Wonder if nearly 15 years of heat cycling caused it to be more brittle than expected.

Good thing these machines are now ancient and parts are a lot cheaper than they used to be...

If you are not sure that you can replace the RTC battery holder, then the SPI flash memory will be something way out of your comfort zone.

Get a replacement backplane, you can get one from eBay for around $70 with shipping in the continental US, also take a look local e-recyclers, Marketplace and Craigslist, maybe you can get a working Mac Pro for little more, the parts will be very useful and can make you some money later.

If you have an early-2009, you need an early-2009 backplane. For a mid-2010 Mac Pro you can get a mid-2012 backplane and vice-versa but not an early-2009 one.