PCB 2060-771642-001

1. The son of a friend put 19V on a WD20EARS. It doesn’t spin…
I thought it was the TVS diode that burned. I removed a diode “D4” which was shorted (I mean let pass in both ways, sorry for my bad english).
The PCB P/N is 2060-771642-001 REV P1.
I can’t see other component burned, but unfortunately it was not enough to repair. Does someone now if I have to replace this TVD Diode on this particular model ? What other component may I test ?
By the way, the other diode “D3”, on the right corner, seems good but I’m not sure what should be the values.

2. I need a replacement PCB for a Western Digital Caviar Green 1.5TB SATA drive. I accidentally applied power with reverse polarity and melted at least one chip on the PCB.
Here’s the info from the drive label:
MDL: WD15EADS-00S2B0
WWN: 50014EE2ADCDBBD5
DCM: HARCNV2AAB
LBA: 2930277168
R/N: 771642
Here’s the PCB version:
2060-771642-001 REV P1
I see three major parts on the underside of the PCB – a Marvell SOC (main processor), a SMOOTH chip (motor controller), and a Samsung memory module.
Here’s the info for the Marvell chip:
8818945P-TFJ2
YPMT014AW
0927 COP
Here’s the info for the SMOOTH chip:
L7251 3.1
The SMOOTH chip is the only one that’s visibly damaged. I’m hoping that any custom parameters for the drive are stored on the Marvell chip.
So.. does anyone have a replacement PCB? If so, which chip(s) do I need to move over from my broken PCB?
If I can’t find a PCB that matches, can I get away with just replacing the SMOOTH chip?

Order this pcb online: Western Digital PCB 2060-771642-001