As title says, I thought I was using the right cable, but for some reason I had an old psu cable between my psu cables, and I fried my Hard Disk. If the pin out I find it's the right one, the top one is the old psu (the cable I used) and the bottom one is my current psu, so I sent like 5v, 3.5v, 12v into ground e 12v into 5v if I'm reading correctly.
The harddisk doesn't power on (obviously). I found this post and I tried testing: the ones on the left have no current.
So I tried searching on the web, and I tested continuity on the "three big top black sqaures" near the sata port on the top right (the vertical ones with written 74, y4 and I can't read). There is continuity.
Do you have any suggestions? Is there something else I can test/do?
Thank you in advice.
EDIT: forgot to say it's a Toshiba P300 3tb - HDWD130 drive rev ara aa34 / cf0
Also I was looking for donor boards online but seems like I can't find one, also, I'm located in Europe.

There are two 4A smt fuses. The 5V fuse appears to be open (blistered).

TVS diode FAQ:

http://www.hddoracle.com/viewtopic.php?f=100&t=86

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A backup a day keeps DR away.

Hey, thank you very much for your answer and the resource you linked! That was super duper useful!
I hope I understand correctly, so if I'm wrong please correct me. I'm not sure if this makes sense, but continuity on 5V TVS looks like in one way works, the other ones the continuity is absent. So I tested with power on the board, and one way of the 5v diode has correctly ~5V, the other is 0. I also tested the other diode/fuse you highlighted, and they appear to have voltage on both sides!
So a replacement for the 5V TVS diode (SMAJ5.0A) should suffice, right? I also found what looks like to be my board for ~8€ on Aliexpress (not sure if links are allows), where should be sufficent just swap the bios chip, right? I don't know which one is easier and maybe safier. Is it possible I damaged something else?

Thank you very much for your time.

I wrote a message, I don't know if I just can't see it or it didn't go through.
First of all, thank you very much for your time and the link you posted!
So, I did not know I had to test continuity swapping poles. It looks like in one way I do have it, if I swap positive and negative I don't have it anymore: I don't know if it's a me thing or it's just supposed to be like that.
So, I connected my board to the power and with black on gnd I tested everything you hightlighted on your picture: it looks like one side of the 5V TVS diode hasn't current, suggesting it is infact open. The other ones looks like they output current correctly, is it right?
Is it possible I damaged something else other than the 5V TVS diode?

Also: I found what should be my board (same board number, same Main Controller IC) on Aliexpress for ~8€, while SMAJ5.0A (from your link, those are the one I should buy) are like 1€ for a bunch, but I only do have a solder pen (I don't know what it's called in english) and the bios chip should be easier to replace with it, right? But I could try first with the diode, is it possible or is it just a waste of time to try?
Do you have any suggestion, something to add, correct, anything?
Thank you very very much for your time and your knowledge.

Ops. double posting and I can't edit my messages.
In the time I waited for my message to be approved, I cleared out some confusion: in my head I didn't have very clear what a diode was and kinda of confused with a fuse, also because of the link you sent talked about tvs and I did not understand it well (as english is not my first language).
As per my messages, the diodes should be fine, they have continuity by one side (in one direction).
The fuses have voltage when connected, but they don't have continuity. Also, now they look both popped.
I think I did some errors while measuring on live (my hands are not steady).
Also, reading around (you posted it, kinda funny): and that's what probably I did with the wrong psu cable, so I'm increasily getting worried.
The board I found has the same board number, the same controller, but there are some different codes and different sticker. For example I have a sticker saying but the title of the insertion is
also there are some other differences and I don't know if they are compatible at this point. Should I try bridging both fuses? Should I try with this board I found? Do I risk some (more) permanent damage if the board is not the right one? Is this hdd probably a goner, did I probably do some more damage?
Thank you in advice and sorry for the multiple messages and the wrong stuff I wrote.

If a diode is shorted, remove it. If a fuse is open circuit, replace it. Retest for shorts at each diode's pads. If there is no short, you can try to power up the PCB.

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A backup a day keeps DR away.

So, I felt not really comfortable doing what you suggested me. I bought the PCB from Aliexpress, I swapped the bios chip and at the first connection Windows could not initialize it, but once rebooted I had access to all my data for 8€!
Thank you very much for your time and your knowledge and your patience!
I would mark this as solved, thank you again!