Need help with WD80EMZZ-11B4FB0 dead 12V rail after 19v char

[Pandemicc]

Hello everyone, I have a WD80EMZZ-11B4FB0 with me that died after plugging 19v laptop charger.

- At first, nothing was shorted to the ground then I went ahead and followed the 5v rail, which was present, then 12v and found out that 12v dies at schottky diode.

- I removed that 12v schottky diode but still not reading 12v on its pads and past that. What could be the issue here? Do you think the trace is gone?

Thanks in advance

Attachments

[SWM]

Check the protective diode and solder it to the board if it's not shorted. Observe polarity! Replace the fuse (in the red circle, closer to the plastic). I think so, since it's hard to see in the photo.
If you don't install the protective diode, but instead use a jumper instead of a fuse, the HDD can be thrown out the next time there's a power surge.

[Pandemicc]

Check the protective diode and solder it to the board if it's not shorted. Observe polarity! Replace the fuse (in the red circle, closer to the plastic). I think so, since it's hard to see in the photo.
If you don't install the protective diode, but instead use a jumper instead of a fuse, the HDD can be thrown out the next time there's a power surge.

But if the 12v fuse is shorted the next SMD in the line wouldn't show 12v reading... am I wrong?

[SWM]

I don't know how to explain something so simple. Compare it to the 5V line. It's the same, just the protective diode is for a lower voltage. Sorry.

[Pandemicc]

I don't know how to explain something so simple. Compare it to the 5V line. It's the same, just the protective diode is for a lower voltage. Sorry.

I did exactly the same thing, comparing, that is why I think the 12v fuse is okay.

Also, just found out that this is my second post about this exact same model, just different drive this time of course. I was successful with the other one.

[fzabkar]

Measure the resistances of the 12V fuse and BG diode.

[Pandemicc]

Measure the resistances of the 12V fuse and BG diode.

both are 170ish or 0.3 in diode mode

[fzabkar]

Remove the diode and replace the fuse.

[Hardcore Games]

Looking at the supplied photo, it dismays me that hard disks do not use a MOSFET to manage power faults

A simple current sense resistor can switch the MOSFET on or off.

Voltage injection can sometimes find a faulty part and tombstoned parts can be tested before resoldering. Precision meters are less costly now. Scopes are also far less costly.

[pepe]

A simple current sense resistor can switch the MOSFET on or off.

do you know what you are talking about?

[WebClaw]

@Hardcore Games, mosfet protects against overcurrent, not overvoltage (19V).

[Pandemicc]

Measure the resistances of the 12V fuse and BG diode.

This is the current condition of the PCB. I removed the TVS diode and replaced the fuse and it worked, thank you so much once again. I got confused when reading 12v in that little neighbour SMD, I should've followed the two 12v traces more carefully.

I really want to stock up those schottkies, TVS, and fuses. where can I find their specs and model numbers?

also, what the hell @Hardcore Games, LOL.

Thanks a bunch again!

Attachments

[fzabkar]

12V TVS diode -- SMBJ12A or SMCJ12A, depending on dimensions

5V TVS diode -- SMAJ5.0A or SMBJ5.0A or SMCJ5.0A, depending on dimensions

Littelfuse Surface Mount Fuses, N = 2A, S = 4A:
http://www.farnell.com/datasheets/48294.pdf

Schottky diode -- 1A, 40V (this diode hardly ever fails in this application)

[Pandemicc]

12V TVS diode -- SMBJ12A or SMCJ12A, depending on dimensions

5V TVS diode -- SMAJ5.0A or SMBJ5.0A or SMCJ5.0A, depending on dimensions

Littelfuse Surface Mount Fuses, N = 2A, S = 4A:
http://www.farnell.com/datasheets/48294.pdf

Schottky diode -- 1A, 40V (this diode hardly ever fails in this application)

thank you so much Sir!