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Data recovery and disk repair questions and discussions related to old-fashioned SATA, SAS, SCSI, IDE, MFM hard drives - any type of storage device that has moving parts
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Seagate Exos 18 PCB Repair

October 1st, 2025, 0:15

Hi Everyone,

I recently swapped out my power supply, but the SATA cable that came with it was for a different model. Since then, my HDD hasn’t been spinning. I ordered the same PCB from eBay, and now the drive does spin and is detected — but the reported size changed from just under 14 TB to 14.5 TB, which makes me hesitant to use it.

From what I’ve read, I may need to do a BIOS/ROM swap, but the ROM chips on this drive are really small. I’ve also seen suggestions that it could be a diode issue, but when I check with my multimeter, I get similar readings on both the old and new PCB.

Has anyone dealt with this before? Any tips on how to properly diagnose the problem would be much appreciated.

HDD Model: Seagate PCB 100852967 REV C
Attachments
PCB2.JPG

Re: Seagate Exos 18 PCB Repair

October 1st, 2025, 2:01

This photo suggests that this model has a unique key in the MCU:

https://ae01.alicdn.com/kf/Sea692b1527fd46b8a01c160eafbb29baa.png

Unfortunately, neither photo is clear enough for me to help you.

Re: Seagate Exos 18 PCB Repair

October 1st, 2025, 3:12

Is this any better?
Attachments
PCB4.JPG
PCB3.JPG

Re: Seagate Exos 18 PCB Repair

October 1st, 2025, 4:35

In the top left corner of the first photo, all I see are black squares. Hint: if you can't see the part markings on the ICs in your photos, then neither can we.

Re: Seagate Exos 18 PCB Repair

October 1st, 2025, 17:08

This PCB has the same two e-fuses:

https://forum.hddguru.com/viewtopic.php?p=314231#p314231

Re: Seagate Exos 18 PCB Repair

October 1st, 2025, 23:10

Hopefully this tells you something.
Im starting to think a bios/rom swap might be easier at this point.
Attachments
WIN_20251002_11_08_42_Pro.jpg
WIN_20251002_11_08_37_Pro.jpg
WIN_20251002_11_08_27_Pro.jpg
WIN_20251002_11_07_55_Pro.jpg

Re: Seagate Exos 18 PCB Repair

October 2nd, 2025, 4:08

Measure 12Vout and 5Vout as marked in that other thread.

Re: Seagate Exos 18 PCB Repair

October 9th, 2025, 1:29

X18 pcb is not universal, even if the rom chip is changed, it will not help.

Re: Seagate Exos 18 PCB Repair

October 9th, 2025, 1:42

The pcb removed from the Seagate hard disk of this label can be used in common with other X18s.
Attachments
Screenshot_2025-10-09-13-37-36-79_0dff84d2da4d0ad536cbb4d749024dd6.jpg
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