So I'm running Unraid 7 on a computer that has been working fine. It is an Intel Mobo with a LSI card in there, with 8 drives on it. It has been working fine for a very long time.

The HDD configuration are all 12TB SATA drives - mainly WDD, but some Seagate, with a 14TB WDD Parity drive. Recently we had an issue with the parity drive failing, so I got a replacement 14TB WDD drive. The replacement drive is almost identical to the original one - both are Ultrastar drives.

When I put the new drive in, nothing. No sign of life on it at all. I can't feel anything in there even giving a hint that it is getting power and spinning up. But if I put the original drive back in there without any changes, it spins up and is recognized.

Out of interest, I put a 12TB drive that I had spare on there to see if I could use that for parity. Again, no sign of power or life on that drive either.

Either I have a really strange coincidence that 2 drives are DOA here and won't power up, or there is something that suggests an incompatibility in there?

Has anyone seen this before? Any thoughts? I changed out the PSU on the box from an 850 watt to a 1000 watt supply, thinking that maybe the thing was being overloaded, but no difference at all.

Is there some subtle difference in drives that work in this config vs. those that don't? The 14tb drive I put in as a replacement shows as being the same, but built 6 months prior. I would have thought that it would at least be an option, but I guess not.

What do you guys do when it comes to replacement drives in this situation? Has anyone experienced this before, and if so what was your solution?

Thanks in advance for your thoughts.

Sounds like a pin3 / 3.3V issue - Some SATA drives use pin 3 to power down the drive.

Fixes include using Kapton tape to cover pin 3 on the drive, or using a SATA to Molex adapter. Search "3.3v pin issue" with Google to get the full story.

You can even cover the first three pins as the first two are not used at all, makes it a bit easier to cut the electrical tape to size. I have 10TB shucked WD Elements drives which I had to tape of the first three pins and then had no issues with them.

On 4/17/2026 at 6:00 PM, ConnerVT said:

Sounds like a pin3 / 3.3V issue - Some SATA drives use pin 3 to power down the drive.

Fixes include using Kapton tape to cover pin 3 on the drive, or using a SATA to Molex adapter. Search "3.3v pin issue" with Google to get the full story.

You guys are all freakin' amazing. Yep, that was it. When I put the 14TB on a Molex adapter, the damn thing showed up. I'm back online. Thank you all!