WD Green SSD with burnt components at power input

[jtb1982]

Hello everyone!

This week, one of my clients gave me a WD Green SSD, model sn350. Two components located at the power input, a zener diode and a 6-pad BGA IC, had burned out. I assume that the IC had the function of waiting for the power to stabilize before activating the PMIC. I am attaching a photo of the board focused on the power input area after removing both the zener diode and the IC. For clarity, I have marked their positions with colored rectangles. The zener diode was in the yellow rectangle and the IC in the red one.

Using a multimeter, I measured the continuity between the two pads on the left of the IC, which I numbered as 1 and 2, with the top left end of the capacitor. The two center pads and the bottom left pad, numbered 3, 4, and 6, receive 3.3v directly from the input. The only pad I couldn't identify is number 6.

Since I don't have a donor to replace the burned components, I am thinking of joining pads 1 and 2 with pads 3 and 4 to solve the problem, but before doing so, I would like to consult whether it is a good idea.

I am also attaching a photo of the BGA IC. I tried to look up the codes written on the package on the Texas Instruments website (https://www.ti.com/packaging/docs/partl ... sp#divline), but without success. The IC have 2 code parts written 17A6YCI and 28203.


Thanks very much and my best regards to all, thanks to read

Attachments

ssd.png (535.59 KiB) Viewed 4323 times

[fzabkar]

Pin #1 is the large dot. Pins are numbered anticlockwise. You have mentioned pin #6 twice. Did you mean pin #5 the second time?

Is pin #5 connected to DEVSLP on the interface?

This PCB has an "AF" or "RF" part in the same place:

https://www.servethehome.com/wp-content/uploads/2022/03/WD-Green-SN350-1TB-Front.jpg

The diode would be a TVS diode rather than a zener. (A TVS diode is much faster than a zener.)

I expect that U3 is a switch of some kind, eg MOSFET, load switch, e-fuse.

Try to identify the date codes on the major ICs. That should help to identify the date codes on U3.

Do your 1 and 2 pins connect to more than I capacitor? If so, then this would suggest that it is a 3.3V output from the IC rather than an output from an LDO regulator.

[fzabkar]

The fact that U3 does not have a ground pin (?) suggests that it is a MOSFET.

The alternative part is marked "AF":

https://images.mltrade.ru/images/photo/n/x/a/579443-078088-4.webp

[fzabkar]

PMCM6501UPE, P-channel enhancement mode MOSFET, -20V, -7.3A, Nexperia, marking AF, WLCSP6:
https://assets.nexperia.com/documents/data-sheet/PMCM6501UPE.pdf

You should be able to bridge the drain and source pins. However, I would first confirm that there are no shorts at the inputs and outputs of the PMIC.

Attachments

[jtb1982]

PMCM6501UPE, P-channel enhancement mode MOSFET, -20V, -7.3A, Nexperia, marking AF, WLCSP6:
https://assets.nexperia.com/documents/data-sheet/PMCM6501UPE.pdf

You should be able to bridge the drain and source pins. However, I would first confirm that there are no shorts at the inputs and outputs of the PMIC.

FZABKAR THANKS VERY MUCH, I AM VERY GRATEFUL FOR YOUR HELP

SOON I WILL DO TESTS

[jtb1982]

Hello everyone!

I am able to recover the data doing a short circuit between the pads of SOURCE and DRAIN.

Thanks very much, FZABKAR