The hard drive is recognized as 3.8 Gb It should be 2000 Gb

I ordered a PCB for Seagate hard driver.

I installed and replaced the bad one on the hard drive.

Then the hard drive is recognized as 3.8 Gb

It should be 2000 Gb.

So I compare the PCB #s

The old one is 100617465 REV A

The new one is 100617465 REV B

Can you tell me whether this is the problem.

Let me know what should I do now to recover the data.

When you get this PCB, you need to move your original PCB’s BIOS to the replacement PCB. The 8pins (4 pins on each sides) with 25P05VP、25P10VP、25F512、25F1024、25F1024AN、SST25VF512、SST25VF010, etc. are the BIOS.

You can move the BIOS from your original PCB by using hot-air gun, then solder it on the replacement board. Please refer: https://www.hddzone.com/hard_drive_pcb_firmware_transfer.html.  Or you can find an electronics repair shop help you.

One chip at lower left says 25X40BLS09, Winbond. Is this it ?

Yes it is the BIOS.