If after I've swapped the hard drive PCB with firmware and also the write head on a WD 2TB drive, the drive now powers on and spins nicely but is not detected in Windows. What is the issue to check for and how and what tools? Thank you

Drive still spin when connected - or does it power down?
BTW: firmware is not on the PCB which creates red flags for us. Additional definition of "write head" also makes the red text bold.

Model number?

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A backup a day keeps DR away.

Can you give me steps for both scenarios of drive still spins and also drive powering down after a short time? Also, the company I purchased the donor PCB said they need to swap the BIOS firmware from old to new PCB. Model: WD20EFRX

Model: WD20EFRX

I am confused. Did you swap the ROM or not?

If your using a non-native PCB with a non-native ROM, then the drive will not work. Period, nothing more needs to be said.

If you did swap the ROM (or are using the native PCB w/native ROM) and the drive starts and then spins down you most likely messed up the heads swap and / or there is SA damage and / or you have a bad head.

Have you swapped heads w/successful results before?

IIUC, you purchased a PCB, including ROM swap, from another supplier prior to your head swap attempt. If that is the case, have you tried the other PCB and ROM from your donor HDD on the patient after the head swap?

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A backup a day keeps DR away.

Yes that is the correct scenario that transpired. I did not try what you have suggested. Thank you

Poster above or below has summed it up. In what scenario does the hard drive firmware need to be rewritten due to corruption? Is that what you call SA damage?

SA = Service Area - a location on the disk which has firmware on it.
UA = User Area which contains your data.

FW is read by the heads. If FW cannot be read it's likely heads are at fault.
FW contains unique information, you simply cannot rewrite FW.
If SA cannot be read UA cannot be accessed = No access to your data.

You need to determine if you can access SA. Assuming you moved heads w/o issues (eg: proper compatibility and in working order) + there is no SA (surface damage) you can adjust head map to 0000 and / or 1111 and see if you can access SA. Averaging 47 may help.

This may seem "cryptic", not trying to be a jerk, but w/o proper tools to diagnose it's hard to assist further.

For the other DR folks, not sure if this head a 2 platter model, but the facts are the same.

Thank you. SA is where FW is located on platter? If I change head map to 0000/1111, is there irreversible or negative effect? What does that change do exactly?

Yes.

Changes what heads are used to read FW. Effectively 0000 disables all heads aside from 0; and 0 is used to read FW. It's a common diagnostic process a DR lab will use to determine if a head is at fault or if surface damage is present. DR company will do this in RAM.

yes, don't do that.

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Adatmentés - Data recovery