Samsung EVO 870 500GB

[managerharry]

Got a Samsung EVO 870 500GB model. Drive died suddenly. Is not detected in BIOS. Would like to recover the data. Wondering if someone can help with some guidance on probe points and methods to identify the fault. Photos attached. Thanks.

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[fzabkar]

This is sounding like a problematic model:

https://goughlui.com/2022/08/20/notes-s ... e-trusted/

I can show you the voltage test points, if necessary.

[managerharry]

Yes, I did come across that posting. I'm hoping perhaps it's a blown efuse, as seems to have been the case with a number of other Samsung models. Although a lot of those seem to have been caused by incompatible modular PSU cables being used, which was not the case here. Some guidance on probe points would be greatly appreciated. I assume circled chip is efuse?

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[fzabkar]

It does look like it's in the right position for a 5V e-fuse. I expect that the two unpopulated square pads would be 5Vin and 5Vout.

[managerharry]

here's a closeup

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[fzabkar]

TPS259535, Texas Instruments, 2.7V - 18 V, 4A, 34-mΩ eFuse With Fast Overvoltage Protection, 5.7V clamp, marking ES35, WSON-8:
https://www.ti.com/lit/gpn/tps2595

I was wrong about the pads. You need to check pins 3,4 and 5.

[managerharry]

getting 5v on pins 3,4, and 5.

[fzabkar]

TPS22975DSGR, Texas Instruments, 0.6V - 5.7V, 6A, 16mOhm Load Switch, marking 13XH, WSON-8:
http://www.ti.com/lit/ds/symlink/tps22975.pdf

TPS22990DMLR, Texas Instruments, 0.6V - 5.5V, 10A, 3.9mOhm Load Switch, marking RB990, WSON-10:
http://www.ti.com/lit/ds/symlink/tps22990.pdf

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[managerharry]

readings attached

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[fzabkar]

V3 and V4 seem low. Could they be core voltages?

What are the voltages on the tiny bypass capacitors surrounding the NAND flash? Are these supposed to be 1.8V/1.8V NANDs or 1.8V/3.3V?

[managerharry]

readings attached

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[fzabkar]

It looks like this NAND requires 2.5V and 1.2V.

I don't understand the 0.6V capacitors. Could they be the boost voltage (12V)? I have been told that this voltage is present during writing, so perhaps there is a transistor or load switch which is currently turned off.

Internet searches tell me that Samsung's "Metris" controller has 3 cores, so perhaps V2, V3 and V4 are the Vcore supplies. If so, then I would expect that the resistance between ground and each of these test points should be of the order of 100 ohms or less.

In short, it looks to me as if the hardware is probably OK. I think you need to find the ROM/Safe Mode test points.

If you want to exhaust all possible hardware avenues, try to identify the markings on the smallest ICs and transistors. These are located near the SDRAM, crystal, unpopulated NAND, and load switches. I suspect that the small rectangular IC adjacent to the unpopulated NAND may be a load switch for the Vboost supply.

[managerharry]

Thank you fzabkar! Probed around and found the safe mode test points, jumped them and gained access to data. ddrescue imaged drive with 99.99% recovery! Here's the safe mode test points

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[fzabkar]

Did you use some kind of loader??? AIUI, the 870 Evo isn't yet supported by data recovery tools.

[managerharry]

No, didn't need to. I assume it was jumping safe mode test points that did the trick, but maybe it just was powered on long enough to finish reallocating bad blocks and come out of busy mode? I was able to remove jumper wire and drive was still recognized for what it's worth.

[Lardman]

Did you use some kind of loader??? AIUI, the 870 Evo isn't yet supported by data recovery tools.

Very occasionally you will get a case where kicking it into safe mode and then out again will give you access for long enough to clone it.

[managerharry]

Supposed I'll count my lucky stars on this one.

[Lardman]

I'd be tempted to recheck those low voltages, just out of curiosity.