MP 1,1-5,1 MacPro 5,1 PCIe slots 3 and 4 partially broken?

[zterm]

I have a 2010 MacPro 5,1.

About 4 years ago, I replaced the original video card with an RX580, and added an Inateck USB 3.2 card (slot 4). Later, I added a Wi-Fi/Bluetooth card (slot 2), and more recently an NVME drive (slot 3).

Interestingly, aside from some occasional issues during the Monterey installation, everything works fine with Mojave and Monterey.

Since adding the NVME drive, I started noticing occasional disconnects of the connected USB drives while working, but the rest of the PCIe devices continued to work perfectly. I thought it might be due to the USB card failing, so I ordered a new one.

Before the new card arrived, one day the screen went blank, and I had to restart the machine a couple of times. But everything continued to work, even the USB card.

When the new card arrived, I removed the old card and installed the new one. After a while, it started ejecting the drives again.

Suspecting it might not be the USB card, I swapped the NVME drive and the USB card and found that the card, despite the LED turning on, was no longer functioning. I tried with the old card, but it didn't work either.

So, I removed the NVME drive from slot 3, moved the Wi-Fi card from slot 2 to slot 4, and placed the USB card in slot 2. It works fine there, and I haven't experienced any problems since then. However, because the card partially covers one of the fans of the RX580, I am afraid that either card could get damaged.

After this, I made a couple more swaps and noticed that:

Slots 3 and 4 don't seem to recognize the USB card, although they do recognize the Wi-Fi card and the card with the NVME drive.

From what I've read, slots 3 and 4 may have been partially damaged, but I'd like to be able to repair this machine since it's my only option for running old software on High Sierra and Mojave, which I use the most.

To rule out driver issues, I've booted with Monterey, but the USB card remained unrecognized, despite the LED indicating power.

I would greatly appreciate any suggestions or methods to confirm whether the board is damaged and if there exists a process to restore its functionality.

Rod

 

[Macschrauber]

Slot 3 and 4 are going thru a PCIe switch, those can get defective.

I have a 4,1 backplane board with that symptom what I now use as a test bed for this reason.

 

[zterm]

Thanks. Do you think I am risking ports 1 and 2 and/or the RX 580 by using the computer the way I described above?

 

[Macschrauber]

You can't say that. You may measure if there are voltages at the ports, afair there are fuses (at the backside of the board).

I use my test bed (with broken Slot 3 und 4) for years and have put many cards in Slot 1 and 2. But no one knows what exactly is havoc on your board.

 

[zterm]

You can't say that. You may measure if there are voltages at the ports, afair there are fuses (at the backside of the board).

I use my test bed (with broken Slot 3 und 4) for years and have put many cards in Slot 1 and 2. But no one knows what exactly is havoc on your board.

As both the NVME drive and the WiFi/Bluetooth card work fine in ports 3 and 4, I guess they are not completely broken and wonder if those fuses could be reset or repaired.

I could also buy a used 5,1 backplane, but not many options where I live and impossible to know if all the ports (and everything else) will work as expected.

Again, thanks.

 

[tsialex]

wonder if those fuses could be reset or repaired.

The resetable fuses can be easily replaced with a hot air station or even with low melt solder, its located on the backside of the board and you can easily test them with a multimeter set to continuity.

Before you ask where you can get one, I usually take from a dead backplane.

 

[zterm]

Thanks Tsialex.
I own both a SMD soldering station (bought it a while ago to replace a failing GPU smd cap in my old MacBook) and also own several controlled temp soldering guns, but to be honest, I don't know if I feel capable of carrying out the process, despite having successfully repaired my MacBook and several Apple monitors that had a failed regulators.

How difficult is it? Will any dead backplane be a good donor?

 

[tsialex]

How difficult is it? Will any dead backplane be a good donor?

While seems a weird component with that metal cover (probably to avoid electrical discharges outside of the fuse) is not too much difficult to replace it, takes some pre-heating and a lot of solder flux that you need to clean later.

Will any dead backplane be a good donor?

Any backplane from early-2009 to mid-2012, do not matter since call three have the exact same resetable SMD fuses.

 

[zterm]

By chance do you have on hand an image of the location of the fuses in question on the board?
Thanks!

 

[tsialex]

By chance do you have on hand an image of the location of the fuses in question on the board?
Thanks!

There are probably around two dozen fuses all over the backside of the PCB, I've marked the two different types for you to get an idea:

 

[zterm]

Thank you very much Tsialex!
It does not seem to be very difficult to repair it.