after about 20 testing head swap in some used and old hard drive, i have got my first one without demaging the heads.
but after i powered the drive i have got this results (pls see the video)

Looks like the drive is trying to init, looking for SA and not finding it, then after 3 times giving up.
Are you sure the donor heads are compatible, or are they the native heads that you were just practicing with? Perhaps you contaminated the platter or damaged it? Or you have alignment issue? Or perhaps heads are damaged but you don't know it - static killing preamp? Could be lots of things.

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Death is nothing, but to live defeated and inglorious is to die daily.
Data Recovery Cape Town

Hi i am not sure about head compatibility, i have got the same model, the same date, same country, but the DCM is slightly different.
about static i was grounded, and i opereted in a clean bench.
i checked the donor, and it had not bed sectors, even if the firmware was not all readable.

I don't think a WD 5000AAKS is the easiest drive to do head swap on
You know what you should do for practice, get a working drive that is 100% functional and then practice with taking off the headstack, and then putting it back. Then you know that if it doesn't work that it's not issue like incompatibility or something like that, but your method that is the problem. Once you can successfully take off a drive's HSA, and put it back, then try doing it with compatible donors.

_________________
Death is nothing, but to live defeated and inglorious is to die daily.
Data Recovery Cape Town

hi, i made this test: i put again back the HSA to the donor, and the drive works i can write and read the files and forders by os.
so at this point, i guess, it can be only the compatibility issue..
HBNNNT2CA may be is not compatible with
HBNNHV2CA (patient)

If you have a seach around you'll see that some people say that 6th character of DCM relates to head stack, so in your case they are different. Perhaps that's the problem?

I've had alignment issues with 80GB WDs, and you're working on a 500GB where the density would be higher, so I'm surprised you're not having alignment issues when you put the original heads back. I've heard that only certain families of WDs have this alignment issue, but I don't how know true this is. I think this is something that can only be figured out by practice and trial and error, no one will share this info.

_________________
Death is nothing, but to live defeated and inglorious is to die daily.
Data Recovery Cape Town

Si vede che non avete mai visto sostituzioni di testine che apparentemente non avrebbero mai dovuto funzionare. Li' la differenza la fa quella cosa che maneggia gli attrezzi. Ma capita anche che quello che dovrebbe funzionare per forza non va. Stessa storia.

So you haven't seen yet headswap that apparently should have not worked. The difference is made by who handle the tools. But also happens that an apparent "must-straightforward-work" job doesn't work at all. Same conclusion applies.