PCB 810035 - WD40NDZW

[n3dv3d]

Hi,

I have a 4TB WD40NDZW-11BCSS0 hard drive ( SpyGlass3 )that doesn't spin up due the faulty PCB.

Since it needs native the USB pcb to read unencrypted data, please do you have some suggestion to try to repair the original board? Are you aware of any “usual” issue that could cause this defect?

[melvin]

Those are fragile PCBs so it might be broken between layers. But it's hard to guess just by your post. There's always a possibility to move ROM and MCU to a new one.

[fzabkar]

Check the fuse and TVS diode adjacent to the USB connector.

[n3dv3d]

Check the fuse and TVS diode adjacent to the USB connector.

Thank you very much for your response... actually, these were the first things I checked, and unfortunately they seem to be working

Those are fragile PCBs so it might be broken between layers. But it's hard to guess just by your post. There's always a possibility to move ROM and MCU to a new one.

I know, but unfortunately I don’t have the proper equipment to move the MCU.

[melvin]

Outsource it. There's no other tool than hotair needed.

[fzabkar]

If you want to troubleshoot the PCB, upload a clear hi-res photo.

[n3dv3d]

If you want to troubleshoot the PCB, upload a clear hi-res photo.

Ok, thank you, I’m attaching the photo. If it helps, I noticed that on the points marked in red, the working PCB has 3V, while the faulty PCB has 0. Generally, the other voltages seem quite similar on both PCBs.

Attachments

[Markello]

I noticed that on the points marked in red, the working PCB has 3V, .

Hi, did you purchase a donor pcb?
these boards have independent ROM chips, according to the picture.
I would read/save the content of the eeprom first, then transfer it to the donor board.

[Markello]

Better picture

Attachments

[Hardcore Games]

There are chip readers that can read ROMs in place. A heat gun, solder, flux and a replacement ROM chip can all be put to use.

Make a backup copy of valued data.

[n3dv3d]

There are chip readers that can read ROMs in place. A heat gun, solder, flux and a replacement ROM chip can all be put to use.

Make a backup copy of valued data.

I noticed that on the points marked in red, the working PCB has 3V, .

Hi, did you purchase a donor pcb?
these boards have independent ROM chips, according to the picture.
I would read/save the content of the eeprom first, then transfer it to the donor board.

Hi,

This drive needs the native the USB pcb to read unencrypted data so move the only ROM chip will provide garbage data.

[Markello]

This drive needs the native the USB pcb to read unencrypted data so move the only ROM chip will provide garbage data.

Hello,

I don't quiet understand, what do you mean by saying "Drive needs the native usb pcb"
Are you saying If you get the same donor and transfer the Flash chip, the trick is not going to work?

Any way, i would try to fix your original pcb first. The motor controller chip also acts as power supply, creating several voltages for the pcb.
You mentioned previously that you see +3 volts on capacitors, on the donor board, but not on your original pcb? This could be an indication of the faulty motor controller chip.

With the hot air station you can easily transfer this chip from the donor board. Requires a bit of experience of course.

My approach is always the same. Read/save ROM (if possible) from the original pcb, then try to fix it.

[Hardcore Games]

I dug around to see what was available for a parts disk and it seems that there are a lot of variants suggesting several batches were made for the USB-C hard disk market. I wonder about that disk as USB logic boards are weird. Doner disks are largely unavailable.

I have USB enclosures for 2.5" and 3.5" so I stick like glue to the standard SATA interface. SAS enclosures are available for weird server disks but modern server disks are SATA as the standard works and refurbished disks are sold off when a data center upgrades to new larger disks.

I buy server disks only as these are larger in capacity. AFAIK my server disks have 8 platters give or take. My Orico 5 disk box is great for redundant copies of important data. Server disks I use have helium in them to reduce friction and allow for full 7200 rpm operation all day long.

[Markello]

You are probably trying to say that encryption keys are stored in the MCU? Am I getting this right?
If this is correct, then MCU transfer is also needed along with the transfer of the ROM chip.
If your drive is SED (Self Encrypting Drive) then original processor (MCU) is needed to "decrypt" user data.

[n3dv3d]

Exactly, that’s what I meant, but MCU transfer is quite complicated.

[Hardcore Games]

If the hard disk is encrypted then it may be impossible to get the decryption key to use on a doner controller board. The MCU is a basic CPU that depends on the ROM that is located on the edge of the logic board.

An 8-pin chip reader can capture the contents but the decryption keys may be inaccessible. It depends on the MCU which may have a cypher instruction. This is why I loath drive based security is favor of bitlocker that is used by Windows.

Dumping the ROM at least will allow some modicum of recovery possibility. Testing the MCU will be dramatically more difficult.

The flash memory is likely to have decryption keys so that is my first choice before diving deeper.