Seagate Expansion SRD00F2 - Cannot identify MOSFET on Controller Board

[puz219]

Hello.

I have external hard drive Seagate, model Expansion SRD00F2 2 TB.

Accidentally I connect the 19V laptop power adapter, and when I smelled that something is melting I disconnect it.

Disk didn't run, so I open encloseure and found two issues - first one is burned TVS diode on drive PCB, which I replaced and disk works properly.

Now i faced with the second problem which is burned MOSFET on controller board.

I desoldered this MOSFET and only text I found on it is X7PV 3P.
I tried to google that, but I didn't find anything.

Can anybody could help mi with identyfying this MOSFET or finding replacement?

Thanks in advance!

 

[pplus]

Why do you think that this transistor is a MOSFET?
https://alltransistors.com/transistor.php?transistor=17507

 

[FvM]

Why do you think that this transistor is a MOSFET?

Because of the D, G S markings?

If I understand right, drain is connected to PATA power supply pin. In so far it can't be but a PMOSFET. I would expect that any low voltage PMOS transistor with sufficient current rating can do the job. I have used IRML6401 and Si2323 for similar functions.

You should be however aware of possible damage of other components due to the overvoltage.

 

[puz219]

Why do you think that this transistor is a MOSFET?

Because of the D,G,S markings, of course

If I understand right, drain is connected to PATA power supply pin. In so far it can't be but a PMOSFET. I would expect that any low voltage PMOS transistor with sufficient current rating can do the job. I have used IRML6401 and Si2323 for similar functions.

You should be however aware of possible damage of other components due to the overvoltage.

Im aware of possible damage, but are you sure, that the MOSFET I need, is the P-type?

I had the N-MOSFET 2N7002 https://www.fairchildsemi.com/datasheets/2N/2N7000.pdf, and I already soldered it to the board and I check the power sections with a gauge, and both, 5V and 12V are working fine, so I connect the board to the drive and drive works fine also.

But, if you said P-MOSFET, I start wondering if the fact i soldered N-MOSFET can damage my hard drive, which I want to avoid?

 

[FvM]

are you sure, that the MOSFET I need, is the P-type?

I made a guess based on the connections that can be seen on the photo (MOSFET drain connected to SATA prower supply pin). You should verify the actual circuit function by voltage measurements and/or tracing the complete circuit. The interesting point is the voltage at Q1 D terminal.

Reviewing the SATA connector pin assignment, I realize that the leftmost pins are assigned to V33 which unsused with most 2.5" and 3.5" SATA drives.

A MOSFET of wrong polarity would act as a diode and supply V33 with about 2.7 V, but unlikely cause circuit damage.

Less likely Q1 could be a NMOSFET with the purpose of discharging V33 to ground (don't know why).