Hello,
Thank you both for your help and reply to my incident.
I had in deed replace only the U12 from the original pcb 771801-002 rev a - original to the "donor" 771823-000 rev a but without sucess. HDD is detected when connected however the disk does not start up. About the donor PCD 771823-000 rev a, it's fully working on the original disk!
I'm adding photos off both PCB's for your analisys.
771823-000 with the following component: U12 - winbond 25x20bl1g
771801-002 with the following component´s: U14 - 25u206a // U12 - 25u206a
Thanks once again for all the help,
Best regards,
Nuno Fernandes
25 January 2019