I forgot to say I tried on other 2 functional motherboards and it causes the same issues. Even in Windows 98 it causes some sort of conflicts.

CoolDoomer wrote on 2024-02-04, 20:17:

I got a Quantum EX 5.1 hard drive that seems to have these symptoms: It has the code: EX51A014 REV 01-B. It should have 5GB. […]
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I got a Quantum EX 5.1 hard drive that seems to have these symptoms:
It has the code: EX51A014 REV 01-B. It should have 5GB.

1. Primary Master IDE is not recognized
2. It throws an error after detecting all Hard Drives.
BIOS1.jpg

3. In bios it identifies wrong C/H/S and Size values.
BIOS2.jpg

3. It makes booting Windows XP Last around 5 minutes.
4. Hard disk sentinel doesn't display any information.
HDDSentinel.PNG

5. Trying to use Atola HDD capacity Restore inst able to identify the factory settings.
untitled2.PNG
untitled.PNG

HDD spins and doesn't sound strange. The green LED on the PCB behind the Hard drive is light and blinking.
I feel this is an firmware issue. If someone with HDD experience can help me, I would be grateful.

Specs attached ...

Try running it as the only attached drive, using the Quantum diagnostic app (attached - creates a bootable floppy)

Thank you. Tried using that. It still recognizes the drive with 000.. serial and it cannot select the drive.

CoolDoomer wrote on 2024-02-05, 07:51:

I forgot to say I tried on other 2 functional motherboards and it causes the same issues. Even in Windows 98 it causes some sort of conflicts.

Here is how it outputted:

modern (as in last 30 years) HDDs keep configuration and firmware directly on HDD platters in special service area. HDD dies if that data gets corrupted and drive cant recover using spare copy. Serial number 00000 looks like drive failed to fully initialize itself.

QUANTUM ECLIPSE PLUS seems like a family model.
Looks like HD couldn't load firmware from platters
and you got ID from PCB bios.
This means usually bad heads or media damage.
I would try unscrewing the controller and clean any
contact between PCB and the HDA and see if this
make any difference.