Question WD120EFBX WD RED Plus 12TB

[Upstate]

Hi all,

I'm having an issue with 3 12TB WD hard drives. There was an issue with my plex server not staying on and I was attempting to troubleshoot it. The PC was start POST and then immediately shut down. I have a separate PC that runs a home arcade I built a couple of years go. I figured the power supply may have gone bad and my Aracde rig uses the same PS. I made the connections using a temporary off/on switch and the unit powered up without issue. Unfortunately while doing this at some point I messed swapped the SATA power cables. It seems I did something similar as this poster: https://forums.tomshardware.com/threads/wd120efbx-wd-red-plus-12tb-no-longer-initialized.3792102/. Three of the drives are not powering on. I've been reading posts and found the following information:https://www.hddoracle.com/viewtopic.php?f=100&t=86. I'm doing my best to try and fix the issue but need some help. I pulled the board from one drive (see attached)
Board Pics. I don't see any obvious damage. In one of the images, I've circled and numbered the parts I believe I need to begin testing with my multimeter. Before I go any further I was hoping for some guidance I which ones I should start with and what numbers I should be looking for. I've tried to include as much information as possible. I appreciate any help.

Thanks!

https://imgur.com/a/xoGoW7j

 

[fzabkar]

The "74" diodes would be OK (unless the supply voltage was reversed). The usual culprits are the 5V fuse and 5V TVS diode (SUA).

 

[Upstate]

The "74" diodes would be OK (unless the supply voltage was reversed). The usual culprits are the 5V fuse and 5V TVS diode (SUA).

Thanks for replying. I appreciate it.

The supply voltage wasn't reversed (I don't think). Was able to get the PC to reboot and Windows started up. However, the 3 12TB drives weren't active. Another 4TB drive was fine and the SSD boot drive was working. When I noticed they weren't active I discovered I had swapped SATA power cables by accident. I fixed the issue with the SATA power cable but at that point, I think the damage was done. I pulled out the multimeter and this is the reading I'm getting from #3 and #6 in my previous marked-up image.

https://imgur.com/jNvYgST

 

[fzabkar]

102 ohms is low, but it isn't a short.

What readings do you get for the two fuses ("s")? They should measure 0.0 ohms, or very close to it.

 

[Upstate]

102 ohms is low, but it isn't a short.

What readings do you get for the two fuses ("s")? They should measure 0.0 ohms, or very close to it.

The fuse on the left (#2 in pic) reads .000. The fuse on the right (#4 in pic) reads 1.

 

[fzabkar]

Fuse #4 is open. Do you have a soldering iron?

You can purchase a 4A smt fuse from places like Digikey, Farnell, Mouser, RS Components. If you don't have the necessary skill to replace the fuse, and you are prepared to accept the risk, you can flow a blob of solder over the fuse.

Littelfuse Surface Mount Fuses, N = 2A, S = 4A:
http://www.farnell.com/datasheets/48294.pdf

Before reinstalling the PCB, test for the presence of +5V and +12V at each side of the respective fuse, or measure the voltages across the TVS diodes.