Hi

I got this HDD with burned smooth chip.
I tried to read ROM (it's embedded into MCU chip), but it can't be read.
I really didn't want to transfer ROM from one PCB to donor
But why can't it be read? Is it usual that a burned smooth kill ROM?
I have tried into kernel and nothing...
Thanks

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You have a fundamental misunderstanding of the function of the motor controller IC. In fact, in addition to controlling the spindle motor and VCM, it also controls the onboard power supplies (including Vcore and Vio) and the POR signal to the MCU.

If you wish to power up your MCU, then you will need to hack the PCB and substitute two external supplies. Then you will need to locate the POR pin and release the reset signal to the MCU. One user has done something along these lines in another thread, but you'll need some basic electronics knowledge.

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A backup a day keeps DR away.

Hi Fzabkar

Thanks, I didn't know that

Can you send the link of where the other user has done that? I could try...
I think it will be easier than swap these MCU chips...
Thanks

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When I said "something along these lines", I meant it as a general observation. In that particular case (Seagate dual core PCB) the motor controller was alive, but one of the Vcore supplies was dead. The user substituted a linear regulator for the dead supply. You would need to try something a bit different.

You might like to explore access via JTAG, but you would need to provide a +3.3V Vio supply and possibly a +1.2V Vcore supply. IIRC, there is a Chinese tool that claims to be able to do this (there was a HDD Oracle thread on this subject). Otherwise there was a thread by _dexx_ at HDD Guru.

A 3.3V supply could be built from a jelly bean 1A LDO regulator running from the +5V supply. A 1.2V linear supply would require a beefier regulator that could handle the higher power dissipation.

Something else that you could try would be to use a donor PCB to supply the two voltages, but you would then have two boards running in parallel from the one pair of supplies. Hopefully this will not overload the donor. This would be potentially the easiest solution because you would only need to run 3 wires between donor and patient (Vcore, Vio and Ground). The only thing left to do would be to locate the POR signal and ensure that it is not holding the MCU in the reset state.

However, before you do anything, I would measure the load resistances on each of the supplies. If either is shorted to ground, then the MCU could be dead.

_________________
A backup a day keeps DR away.

HHmmmm seems a litlle too much for me....
I'll search another options.
Thank You

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