WD23NMVW-11EDZS3 Liquid damage PCB

[johnkeates]

I have a dead WD23NMVW-11EDZS3, the type of 2.5" drives used in WD's externals with the on-PCB ASMedia USB to SATA bridges. Cause of death: water or other liquid got in and over time caused enough corrosion to make it fail electronically. Luckily, only one ceramic cap seems to be dead, the rest is minor surface traces and some via's that need bridging to recover the data; no corrosion near the spindle motor connection pads or the pogo pin interface to the head.

Before I start repairing the power circuits and then continue with the USB and SATA parts depending on what starts working, is there any internal ROM in the WD nautilus or the Marvell MCU? I suspect the motor driver won't have any/special code, but besides the serial flash SOIC8 connected to the Marvell (not the one connected to the ASMedia), might the Marvell MCU itself hold something unique for the drive? If the repair turns out to have damage to internal traces or via's this would obviously turn into a board swap, but knowing ahead of time of that's going to need a BGA reball for that Marvell chip or not would be good to know.

[pcimage]

The SOIC at U12 should be all that’s unique.

[johnkeates]

The SOIC at U12 should be all that’s unique.

Thank you, I suspected as much. I'll dump that one before I repair the DC rails and power it on.

[johnkeates]

Well, the user wanted a 'second opinion' (I suspect the 'pc guy neighbour') and took the drive, then later came back because apparently the liquid damage was real and not made up.

Reading U12 isn't working, can't even detect it properly. Same for the USB-SATA bridge chip's EEPROM (U14 probably, silkscreen rather tight). Desoldered both of them and tried a few readers, no joy. To rule out the tools, I tried reading the same chips from a donor board, those work fine. Since no protection diodes seem to be blown on the board but a lot of tracks are bad/gone (either corroded or burnt) I suspect the damage did something to a DC-DC circuit somewhere and might have taken the SPI chips with them. I haven't tried undervolting or overvolting them during reading, I did try slower speeds, but it didn't change anything (they are detected as 0kb unknown - so the SPI interface works, but the chip spits out garbage).

Anyone here able to recover data without that EEPROM contents or have suggestions?

[fzabkar]

What is the part number of U12? Which programmer are you using?

[johnkeates]

It's a 25U20A, pretty standard. Used a ch341a, Piv3, Bus Pirate, TUMPA, all on 3v3. Tried with SOIC8 clip, didn't work, so desoldered it, put it on a DIP8 carrier and tried that, no change.