Let's suppose that a hard disk has been immersed in water for 2-3 days (water from home, not river or sea) and we are going to swap platters with a hard disk donor.

In case the ROM needs to be the same, that ROM could be worth to be transplanted to new PCB, or the water has already finished with it? In that case....GAME OVER ?

Chances are 0-100%. What else can you expect over the Internet? Remove it, clean it and read it.
I would worry about the platters more than ROM.

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It's just a guess, it's to know if besides the platters you have to worry about the ROM, since being unique for this drive (in many cases) if it does not work, I understand that there is nothing to do.

If it's Toshiba or Seagate and the ROM is dead i think it's over. But i doubt that it would be dead in two days.

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Odzyskiwanie danych
sgdata.eu

ROM chips are pretty hardy. I don't think it'd be an issue unless it has been underwater so long the legs have corroded off.

Also, before I'd resort to considering platter swap I'd give it a chance and see if the motor still works. If it does you might avoid unnecessary calibration issues. But, cleaning it will be fun if water gets inside. Especially if it's salt water.

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Thanks

As already stated i would be worried way more with the platters rather than with the ROM chip. Remove the chip (carefully) and read it with an external programmer that do support your chip. Most likely you will be ok.

Not to say that the same chip would survive years inside water but some days might not be a big issue ...

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