300GB and 750GB Barracuda 7200.10 IDE : PCB compatibility ?

[SOSdonnees]

Hi,

Having to replace the PCB of a Seagate Barracuda 7200.10 PATA with 750GB capacity, I had a hard time finding a donor, especially at an affordable price.

The model is a ST3750640A and the PCB # 100327114.

I could acquire a drive with smaller capacity ST3300620A at a very fair price.
It's also a Seagate Barracuda 7200.10 PATA, but with 300GB capacity.
The PCB number is also the 100327114.

However, I observe on the 750GB model, that the PCB has additional components soldered in one corner.
(see circled areas on the photos).

In order to recover data, does someone know if the 750GB drive requires these additional components or if they are optional?
Swapping the PCBs, the 750GB drive spins well know, but I haven't done the BIOS swap yet.

Second question : does someone know where the BIOS is located on this PCB?
In one of the three 8-pin chips or in the MCU?

Thanks a lot.

[fzabkar]

7200.10 is ST-10 arch.
For this drive you don't need to swap ROM as there are no adaptives on it.
You just need to MATCH ROM version. ROM from your PCB should have the same version of the ROM on the old PCB.

Doesn't the fact that the donor has a lower capacity suggest that there may be a difference in the ROM code? In any case the ROM is likely to be the chip at the lower left corner of the MCU. That should be obvious from its location and connectivity. Googling its part markings would also have confirmed it.

As for the missing components, they are shock sensors and op-amps for sensing rotational vibration. There is one additional component which I can't recognise from the poor photo, but it looks like a diode.

[Martin]

PCB's are not compatible. Look for compatible PCB with similar pair MPU+motor driver IC. If FW on a new PCB is not the same (check info from drive's labels or by terminal log) swap ROM or ROM content to the new PCB.

[data-medics]

Doesn't the fact that the donor has a lower capacity suggest that there may be a difference in the ROM code?

Actually if you analyze the ROM information using PC-3000, you can see a list of all the different capacities that the particular ROM will support.

But, as already mentioned, the two pictured are not cross compatible. I actually find it hard to believe they are the same PCB number having totally different main IC and MC. You sure they're the same number? Is the REV different at least?

[Martin]

Actually, what happend with original PCB? Is it possible (if PCB is not damaged so seriously) to take a look on the terminal log?

In order to recover data, does someone know if the 750GB drive requires these additional components or if they are optional?
Swapping the PCBs, the 750GB drive spins well know, but I haven't done the BIOS swap yet.

Optional (sensors).

Second question : does someone know where the BIOS is located on this PCB?
In one of the three 8-pin chips or in the MCU?

ROM IC marked by yellow number 1 on your picture.

[fzabkar]

ISTM that the two MCUs and motor controllers are at least pinout compatible. It is not uncommon for a manufacturer to seek second sources for critical components to ensure supply. However, the Seagate P/N on the MCU (1004...) appears to differ between the two MCUs, so perhaps they may not be code compatible in every way.