[Help] Disk not found

[TerrorMaster]

Specs:
F6-424 Max
5x 16TB IronWolf Pro Sata drives (5 of 6 populated, no hotspare)
HyperCache - 2x 1 TB Samsung SSDs 990 EVO

HDD1 and HDD2 are labeled system disk
Storage Pool is TRAID+

Running version 6.0.770.00002
BIOS/initBoot version: 5.26

Issue: Over a week ago, started getting beeping from the device. After silencing the alert, discovered that HDD4 had an error condition. I ran manual test on drive HDD4 from the IronWolf Health management. No errors were reported. Checked SMART and manually ran its test. Drive was showing disconnected. Therefore, I decided reboot the NAS. When was back online, the beeps resumes. This time, HDD4 is missing. GUI is showing no drive populated.

Assuming a failed drive (though extremely odd for a drive less than a year old), I ordered a replacement drive. Once it arrived, I shutdown the NAS and replaced slot HDD4 with a new drive. Powered up the NAS. The beeping returned. No hard drive is being detected.

The replacement drive is the exact same model as the "failed" drive.

I tried another power cycle with no change.

I'm stuck.

[Gremlin]

Could be a backplane issue. Bad connection, bad insertion, bad contacts ? Just a thought.

[TMzethar]

After replacing HDD4, which HDD position exhibited the anomaly last? If it is still HDD4, please contact the service team.