Sorry to say: If it experienced a head crash IE… it was dropped or bumped hard while running and the head hit the disk surface and scratched it; you’re not going to fix it. The disk platter it self and head/s would need to be replaced and the heads re-aligned, which takes precision tools, and an O-scope along with a very clean environment. One grain of dust and it’ can be a do over. You’d also have to know what you’re doing; repair manual.
I was a factory trained Tech for WD and CDC drives.
