Possble TVS diode shortage - looking for guidance

[tobz1000]

Hey,

I had a 3TB WD Red (model WD30EFRX) die on me a few months ago. I believe it is a TVS short, but I have very little electronics knowledge, and would like to be sure before continuing.

I would like to get data off the drive; after that I'm not concerned with its long-time viability.

Here's what happened:

At the time it died, I turned on my PC, heard a small click, and it turned off again after about a second. I couldn't turn the PC on again for about a day... after which time, I was able to turn it on; and everything was working, except this hard drive.

It wasn't detected in the BIOS and I don't believe I could hear it spinning up (it certainly doesn't spin up now). So it seems like there was a surge, and the TVS diode was shorted as a result.

So recently I bought a cheap multimeter, removed the PCB and tested some diodes I could see near the power connector: D1, D2, D3 and D4 (see images).

D2 and D4 seem to be working. They both show ".116" (which I guess is 116 mV? the meter has no unit display) with probes connected forwards, and "1." with the probes connected in reverse (the manual assures me this is what I should see in the reverse direction, on functioning diodes).

D1 and D3, however show around 0 in both directions (flickering from 0 to ~0.03; may be down to the quality of the meter...), which I think means they're basically an open wire now; busted.

Can anyone please evaluate/correct my diagnosis?

If I just want to get this drive working long enough to extract the data, can I simply remove the diodes?

Thanks.

Attachments

Close-up (power pins are to the left of diodes from this orientation)

Whole PCB; 4 diodes near power pins labelled

[fzabkar]

Remove D3, then retest it and D1 for shorts. If D1 is now OK, then test resistors R43 and R60. They should measure 0.0 ohms. You will probably find that R43 is open circuit. If R43 is open, then flow a blob of solder over it. Power up the PCB on its own and make sure that everything appears OK. Above all, make sure that your PSU good. The damage to the drive was the result of an overvoltage on the +5V supply.

If you wish to minimise the risk, then replace the PCB and transfer the chip at U12 to the donor. Some suppliers (eg hdd-parts.com) will include such a service in the price.

Attachments

[tobz1000]

Thank you! Very clear instructions. I will have to wait until Monday when I can access a soldering station; I will update when I can.

One more question: how can I tell if the PCB powers up okay without the hard drive attached? Would a PC detect it anything I plugged it into a SATA port, or is there something else to check?

[fzabkar]

how can I tell if the PCB powers up okay without the hard drive attached?

Install the board's PM2 jumper. This should configure it to Power Up In Standby (PUIS). You should then see something in BIOS, although the model number may be blank.