January 9th, 2018, 4:21
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January 9th, 2018, 15:40
abolibibelot wrote:Alright. But what would it entail if there is or is not a ROM in U12 on my PCB ?
And can the owner of the defective HDD attempt something with those diods ?
Thanks for the quick reply !
January 9th, 2018, 22:41
Could You post a picture of the electronic board?
If You do not have external Rom than the rom is located in MCU.
It is possible to recover this rom with PC3000 or rebuild it from SA (using pc3000). Also You can resolder MCU if You have skils Or repair the oryginal electronic board.
Your drive belongs to "Kermit" family. All drives of this family have an external ROM chip ( U12). You have two options:
1. To swap the ROM chips by desoldering / resoldering
2. To transfer the ROM content from one PCB to the other by using a program like WDMarvel, WDR, etc.
This one has no ROM at U12
https://www.harddrivesforsale.com/it/wd ... 01590.html
The problem is NOT if you have or not a ROM chip on your PCB. The problem is that if the damaged drive have or have not a ROM chip.
If the damaged drive doesn't have a ROM chip (external) most likely it will have a copy of the ROM modules on SA. You can place your PCB there and you will gain access to SA with tools like WDMarvel, SeDiv, PC-3000, HRT, whatever and you will read SA and from those modules you re-build ROM (original). Then you write that to your PCB and you are good to go and you will have user area access, assuming the problem is just with the PCB.
If you have a short diode (TVS) then if you plug the drive to a PSU the PSU will shut down, meaning that on internal PC drives with shorted TVS the system will not even power on. If your system is running fine with the drive plugged to it (to the internal PSU) then most likely the problem is not related to shorted TVS.
January 10th, 2018, 1:17
abolibibelot wrote:But again, the defective one is WD10EAVS-32D7B1, not WD10EAVS-00D7B1 which is my (functional) HDD and could be a potential donor.
Does it change the answer to that question ?
January 10th, 2018, 19:48
January 11th, 2018, 5:55
Maybe we are all answering as if @abolibibelot had both disks with him.
@abolibibelot, if you are just selling the disk to a total stranger, as you commented :
- you can not sell it, if it is ok, and sell it to someone that needs a good disk.
- you can sell it, tell the person that you believe it won´t work, and don´t worry anymore. The problem is of the person that insists in buying the disk.
- you can tell the person to send you his hdd, so that you can try to fix it for him ( for a price, obviously )
If there is no ROM chip there will be ROM flash space embeded on the MCU and you can write the code there. The Vendor Specific Commands to access that space are the same ones used to access the external ROM chip. The drive knows if it have to read from ROM chip (external) or embeded ROM on MCU by resistor setting on PCB.
The copy (backup) will be on SA and the working ROM is embeded on the MCU (inside the MCU).
If the drive doesn't spin at all with the defective PCB there might be other issues like for example a shorted pre-amp inside the drive. A shorted pre-amp will make the drive not to spin. Just because it doesn't spin it's not necessarly a PCB issue. Also if ROM code is damaged drive will not spin. If drive have SA/Firmware issues then it have to SPIN. Because SA is written on platter .... So if it doesn't spin at all it will not read SA at all .... For example imagine a bad S.M.A.R.T. module on SA causing problems. If the drive can't spin at all it will not load that model to start with. Only if the drive is spinning the module can be read and if it's damaged will cause a problem ... The problem is way prior to any SA code on the platter to be loaded....
If the original PCB is gone / damaged you most likely can't read the ROM on it with firmware tools. If PCB have external ROM chip then there will be no copy of ROM modules on SA. It's not "viable" to read the ROM with exception of some cases that you might get luck to read ROM by TTL ... But if you have external chip + external programmer (cheap) then problem solved ...
January 12th, 2018, 11:04
March 8th, 2018, 13:19
The damaged PCB and your PCB might or might not have the external chip. You have to check that out on the PCB. even if they have the same model and PCB version there are the chance that one have external ROM and the other have internal one. The only way to be sure is to check.
Only if you are extremely lucky will the PCBs work without swapping the ROM chip or write the native ROM code on the new PCB as there will be adaptives on ROM modules.
Owner can check TVS/DIODES but if the drive is not shorting the PSU and shutting the system down then it will have other issues like open resistor and there will be no short-circuit.
Pre-amp might still be damaged or heads might still be damaged even if the drive spins with a non-native PCB. What we can assume is that the pre-amp at least is not shorted otherwise it would not make the drive spin.
Does the drive clicks ? Does the drive makes a noise of heads reading something ?
If the ROM is inside MCU there will exist a copy of the ROM on SA (platter) so one would replace the PCB with compatible one and use some sort of WD firmware tool to read ROM copy from SA and write it to PCB.
If the damaged drive have a PCB without ROM chip (ROM EMBEDED ON MCU) then you could use tools like the following ones to rebuild the ROM by reading the COPY on the SA and write it back to the donnor (new) PCB
It's very easy if you know what you are doing but can be very complex if you don't understand (fully) what you are doing and you might brick the PCB if you write wrong code to it or if your system does interfeer with the PCB while you are writting ROM (if you don't have hardware based tools like MRT, PC-3000, HRT, whatever ....) This is another risk of software only tools.
March 9th, 2018, 9:51
It would be simpler to read ROM with external programmer and write it to the PCB by Firmware tool.
Don't do it. As soon as you reach the part to "no longer functional" unless it does have extrenal ROM chip that you can re-programm with external programmer or you have a tool that can unbrick the pcb by TTL (and writting correct ROM) you will kill the PCB and you will NOT be able to write ROM back....
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