Hi. I have a strange situation with an ST340014A (FW 3.06). The motor IC is burned. I got hold of two replacement PCB's. First PCB has different site code and P/N. using that pcb, the drive was recognized by bios. In windows, shows correct volume information and I could see the top-level directories. Managed to copy a couple of files, but access was extremely slow. Now all directories were displayed, and most files couldn't be copied. Also, Windows gave some "delayed write failed" errors.
I thought that perhaps I needed a closer match for PCB. Got hold of one with same P/N, board number as well. Drive spun up but was not recognized in bios. Viewed in Seagate terminal and got a couple of Read errors (note: terminal showed no errors when I used the other board). I'm guessing that it was having trouble reading the SA area, but strange that it didn't have the same issue with the non-identical board.
Now, I am confused. The exact match board gives errors and does not work. But a board which isn’t an exact match partially works. So these are the alternatives I'm considering:
1.Attempt live PCB swap using board with same P/N and board no - this way I can bypass the read erros on the SA area (though I realize this can cause a couple of other issues).
2.Attempt to get drive image using board that's recognized by bios (but has different P/N and board no). I would aquire the image using MHDD.

Does anyone have any suggestions? Seem so close to being able to recover the data, I don't want to trip up at the final hurdle...

Many thanks.

Hello mattg,

And what about seeking for someone who can help you to replace only the burnt VCD chip?

Regards,
Janos

Use the PCB that is closest in numbering and design to your bad PCB and swap the ROM from the bad board to the good one.

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which is the ROM chip???

There is no ROM chip on this PCB
This PCB is using mask-ROM

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the MROM is within the hdd controller IC? in that case..... would a hdd controller IC transplant be advisable?

it may seem simplier to just replace the burned motor IC, but other parts of the board may be damaged.

just use PCB with Mask-ROM

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but the motor IC is fried and other parts of the circuit may be damaged....... it does not respond at all to seagate terminal.

just use ANOTHER PCB

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SAN, NAS, RAID, Server, and HDD Data Recovery.

yes that's what i have been doing. but it only partially works as i described at the start

The short-circuit in VCM can hang the MCU.
If you can replace the VCM you may lose nothing, but time.

(When the VCM is desoldered, you need some check for another short-circuits before soldering the new one.)

Regards,
Janos

In this case you need a professional

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SAN, NAS, RAID, Server, and HDD Data Recovery.

I think the pcb u have is not compatible with ur drive try looking for a pcb with same CPU no and motor controller .

when u can access data using donor PCB. it mean Donor PCB compatible with your patient drive.

there is still some another problem except PCB problem.
I suggest send it to a pro

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СУТИОНО / АПИНГ

i would try and replace the burnt out ic motor chip first.
from the donor drive.
easy job to do if you know what your doing.

but once you done this possible might be left with a faulty preamp head chip which is breaking down slowly.

normal if the motor ic chip goes it destroyes other ic on the board
but as you can only see one damaged ic
you might be very lucky.