Being stupid I used a power cable from a wrong PSU (Corsair cable with an EVGA PSU) and fried a HDD. Two, actually, because why not do risky things on two drives at a time, especially if they serve as each other’s backup. Not a complete backup, I am not THAT stupid, important stuff was elsewhere. But I’d be glad if you could recover less important stuff too.
I see that there are very knowledgeable people here, so maybe you could help.
Both were 2TB WD drives.
Yellow WD2003FYYS has big burn marks on major chips so probably hopeless?
The WD2003FYYS PCB probably has a burnt SMOOTH motor controller. If so, then the preamp on the headstack (inside the HDA) has probably been damaged also.
The WD20EFRX has a shorted 5V TVS diode (D3). The 12V TVS diode (D4) is OK.
D1 and D2 are Schottky rectifiers, so they will be OK.
If you wish to risk a repair, remove D3 by snipping its pins with flush cutters, and then flow a blob of solder over R43 and R60.
Otherwise you could purchase a replacement PCB and transfer the ROM at U12. Some vendors, eg hdd-parts.com, will supply the PCB and swap the ROM for US$50 in total.
If you are interested for your own sake, I can post the picture of the WD2003FYYS PCB.
I think I’ll try the “repair” now, as I said important stuff has been backed up elsewhere and I am not sure if I want to spend even $50 on the less important stuff.