Hi! I'd like to try to replace SMAJ5.0A TVS diode on my PCB for the WD4000AAJS hard drive. How can I find it on the board and how it is marked?
Thanks in advance.

Diode at D4 looks damaged

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Hard Disk Drive (HDD), Solid State Drive (SSD, SATA, NVMe, etc), USB Flash Drive and RAID Data Recovery Specialist in Massachusetts

Agree, in which case an SMBJ12A would be a suitable replacement, not SMAJ5.0A.

See http://www.users.on.net/~fzabkar/HDD/TVS_diode_FAQ.html

... and http://www.users.on.net/~fzabkar/HDD/bi ... diodes.jpg

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A backup a day keeps DR away.

how did you know that it is the TVS? is it someone recommended you to do so?

that is the question

thank you

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Kuwait Data Recovery - UNIX GTC
The only reason for time is so that everything doesn't happen at once. By: Albert Einstein

Thank you everyone for the answers. I am not 100% sure if it is one of those diode but I suspecting this. The multimeter diode test show me the following results:
D3 (=5v) resistance: 0.L, 0.5
D4 (=12v) resistance: 0.0, 0.0
so I am assuming that D4 is died. As fzabkar pointed it is SMBJ12A diode.

Yes, D4 is shorted (i.e. failed), as labtech and fzabkar discussed above.

I am still fighting to recover my data from the dead drive. PCB does nor work. I am trying to find the donor drive. Need advice if the following HD can be used as a donor:
MY HD: WD4000AAJS-00YFA0, Date: SEP 2007, DCM:HHRNHT2AHB, LBA: 781422768, Made in Thailand
Potential: WD4000AAJS-00YFA0, Date: SEP 2007, DCM:DHNCNT2MHN, LBA: 781422768, Made in Thailand

Thanks in advance for the help.

The suitable donor you want is readily available, it's only not cheap...

Sorry, not sure what you meant by "readily available"
My question was: "Is the drive I found and called the POTENTIAL WILL work as donor drive OR NOT?"

have you tried just unsoldering the TVS at D4 and then trying the board?

If that works, get the data off and put it on a different drive