Question PCB swap on HDD Hitachi 320Go

[NatureHD]

Hi everyone!

If somebody could give me some advice, it would be great!
Here's my problem [please excuse my english, it's not my native language] :

My HDD no longer starts, no sound at all, not recognized. PCB may be the reason. I want to try to swap a functional PCB ("donor") to the dead PCB ("patient").

Model is : Hitachi 3.5" SATA 320Go
Ref : HDT721032SLA360
Manufactured date : June 2009

Front label mentions :
P/N : 0A38018
S/N : MC35NM8B
MLC : BA3120

PCB mentions :
Board : 110 0A90158 01
Main Chip: 0A58786
Motor Chip: 0A56511
Sticker Number : 0A29989 BA3129
/!\ There is one 8-pins chip in location "U5" labelled "93G86WP B916G". The location "U7" is empty. No firmware chip with a number starting with 25. /!\

Questions :
1. Which specifications and numbers (on PCB from donor) are mandatory to match in order for the HDD (mechanic from patient + PCB from donor) to work?

2. I read that most HDD made before 2010 don't need some BIOS transplant or some soldering ? Is it possible that a simple PCB swap may work ?

3. Is there some risk to do this kind of swap ? My HDD with data to recover (mechanic from patient) could be definitively bricked ?

Thank you very much for your precious answers!

 

[fzabkar]

U5 is the "NVRAM" chip. It must be transferred from patient to donor.

The "ROM" code is embedded within the MCU (Main Chip: 0A58786). You need to match the code in this chip between patient and donor.

https://www.hdd-parts.com/13062124.html

Note: U7 would normally contain the ROM code in those cases where the MCU is not internally programmed.

If you have a multimeter, measure the voltages at L300, L310 (near motor controller) and Q2 (near SATA power connector).