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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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ST9500325AS (Momentus 5400.6, FW 0003BSM1) - spins, never re

August 8th, 2026, 3:31

Hi Everyone,

I have a hard disk I really want to recover. Together with AI, I did some testing and the disc spins properly but is not recognized. Here are the details:


Drive details from the label and PCB:

Model: ST9500325AS (Momentus 5400.6, 500 GB)
PN: 9HH134-567
FW: 0003BSM1
SN: 5VEQL1MW
DOM: 02/2012, site WU
PCB: 100656263 rev D
Base: 100579504

Symptoms: the drive spins up and runs steadily. No clicking, no
recalibration noise, no spin-down. It is never detected, not in BIOS
and not by the OS.

Tested on a direct SATA port (Lenovo ThinkStation P330, Linux, AHCI,
hot-plugged after boot). dmesg:

Code:
[835.077814] ata4: link is slow to respond, please be patient (ready=0)
[839.337799] ata4: COMRESET failed (errno=-16)
[845.089773] ata4: link is slow to respond, please be patient (ready=0)
[849.349709] ata4: COMRESET failed (errno=-16)
[855.101732] ata4: link is slow to respond, please be patient (ready=0)
[884.381554] ata4: COMRESET failed (errno=-16)
[884.381560] ata4: Limiting SATA link speed to <unknown>
[889.413599] ata4: COMRESET failed (errno=-16)
[889.413607] ata4: reset failed, giving up


No IDENTIFY, no model string, no capacity. It never gets past the link
layer.

Control test, same port and same cables, immediately before and after:
an HGST HTS725050A7E630 came up at 6.0 Gbps and identified in about 6 ms.
So the port, the cable and the host are good.

Earlier attempts over USB (LaCie Rugged Mini enclosure): the bridge
enumerates and binds usb-storage, scsi host is created, but INQUIRY is
never answered and the device resets on a ~21 s cycle. No /dev/sd*.
The same enclosure works fine with a Toshiba MQ01ABD050, so the bridge
is not the fault.

The PCB is visually clean. No scorching, no cracked TVS diode, no
damaged components.

What I would like to know:

1. Does this pattern read as a service area / firmware startup hang, or
would you put it elsewhere?
2. Is this generation of Momentus F3 architecture? I understand not all
of them are.
3. If terminal access is worth attempting, where are the TX/RX/GND pads
on board 100656263, what baud rate, and what logic level? I have seen
references to some 2.5" Seagate boards running 1.8V rather than 3.3V
and I do not want to guess.

I am a home user, not in the trade. The drive holds data I have no other
copy of, so I am not going to experiment blindly. If the answer is that
this needs PC-3000 and a lab, that is a perfectly acceptable answer and
I will book one.

Thanks so much.

Kind regards,

Julian

Re: ST9500325AS (Momentus 5400.6, FW 0003BSM1) - spins, neve

August 8th, 2026, 6:23

terminal of 5400.6 runs on 2.5V, likely works ok on 3.3V.
While it is fine for diag, i don't recommend running commands blindly coz you can easily screw up the whole thing. Treat AI advices with reservations. It has nothing to loose, while you do. If the data is worth a pro service, i would recommend choosing that path. If you screw it up by DIY attempts, pro recovery will be definitely harder, consequently more expensive.

pepe

Re: ST9500325AS (Momentus 5400.6, FW 0003BSM1) - spins, neve

August 9th, 2026, 19:15

Thanks pepe, I will not do anything risky with AI, but will try to go one or two steps further and then decide, i.e. will try more diag.

Noted on 2.5V. I would use a 3.3V CP2102 with a series resistor on the
line going into the drive, 38400 8N1, is that correct?

One thing I still cannot find anywhere:

Where are the TX / RX / GND pads on PCB 100656263 rev D?
Are they reachable with the board mounted, or only on the component side
with the PCB removed?

And if you think the COMRESET pattern with no IDENTIFY at all already
points somewhere specific (service area, heads) I would appreciate your thoughts. It would tell me whether reading the log is
worth doing or whether I should just book the lab.

Thanks a lot for your help.

Re: ST9500325AS (Momentus 5400.6, FW 0003BSM1) - spins, neve

August 10th, 2026, 12:34

Show us the terminal log. I have a ZOC script which can modify certain firmware parameters to stabilise your drive.

Re: ST9500325AS (Momentus 5400.6, FW 0003BSM1) - spins, neve

August 11th, 2026, 3:32

Where are the TX / RX / GND pads on PCB 100656263 rev D?

they are the same for all seagate drives next to the sata data connector.
Code:

+---------------------+
| o    o     o     o  |     <sata data connector> <sata power connector>
+---------------------+
vref  gnd    tx    rx


the above is from the hdd direction, ie rx ix data TO hdd, tx is data FROM hdd, connect adapter rx to hdd tx, etc.
gnd, tx and rx is sufficient.

btw, this info is considered common knowledge, i guess you can find it on the net on a trillion pages
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