ST500LX012 - Ultra Mobile SSHD - Short on PCB

[suricate.ch]

Check the enable pin (pin #1). If it is low, then the IC is not being switched on.

LX7188, Microsemi, 1.4MHz, 1A Synchronous Buck Converter, 2.5V - 5.5Vin, marking 7188, UDFN 2x2-6L:
https://www.microsemi.com/document-portal/doc_download/132768-lx7188-datasheet

Pin1 has 5V.

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[pepe]

yeah, that's something, that inductor (large one) should have 3.3V.
you can try feeding it from a lab supply (the right side of the inductor...
Check if it is shorted to gnd, if so, remove the large inductor and check again. If it is not shorted, try feeding it with 3.3V. You might need a switching transistor to apply it in the right sequence, but it is probably sufficient to turn it on first.

pepe

[suricate.ch]

Thanks.

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[pepe]

yes, that one.

[Lardman]

Blown IC ?

[pepe]

i suspect that buck converter is gone, so if everything else is working, the drive can be bootstrapped by feeding it the missing suppy voltage.

[Lardman]

I'm surprised - Id have thought something prior to it would have failed first - live and learn. OP keep us updated on the recovery if you could, especially if you put it on bypass.

[fzabkar]

Instead of a 3.3V lab supply, find an older SATA power cable with 3.3V, 5V and 12V. Then run a wire from a 3.3V SATA pin to the inductor, after removing the IC or the inductor.

[fzabkar]

ICBW, but I think I see a dimple or discolouration between pins 2 and 3. By the way, these DC-DC converters usually have a low input margin, eg 5.5V. The absolute maximum is often 7V.

Last edited by fzabkar on September 24th, 2021, 8:03, edited 1 time in total.

[pepe]

i am usually more comfortable with a current limit i can set, when powering up circuits in an unknown state...
Moreover, he will clone it in pc3k most probably, and there is no 3.3V in that cable.

To Claude:
when i said 'That one' a few posts above, i meant 'That inductor' but you need to feed the 3.3V to the other side, after removing it (or the IC, as Franc said)

pepe

Last edited by pepe on September 24th, 2021, 8:07, edited 1 time in total.

[fzabkar]

i am usually more comfortable with a current limit i can set, when powering up circuits in an unknown state...
Moreover, he will clone it in pc3k most probably, and there is no 3.3V in that cable.

If the OP needs a current limited supply, then the NAND is dead. In any case a resistance test would be advisable before applying power, as you have already stated.

Last edited by fzabkar on September 24th, 2021, 8:12, edited 1 time in total.

[pepe]

- 3.3V is not easily available from the PC3k power cable -> Lab supply is easy
- we don't want to smoke anything -> a current limit just can't hurt, so why not?

perhaps i am paranoic...

pepe

[fzabkar]

- 3.3V is not easily available from the PC3k power cable -> Lab supply is easy
- we don't want to smoke anything -> a current limit just can't hurt, so why not?

perhaps i am paranoic...

pepe

I would hazard a guess that only 0.1% of DR shops have a lab supply.

There is no need to use PC3K for a simple cloning operation if the drive is otherwise OK.

If you really want a current limit, then use a 1A polyswitch in series with the 3.3V wire.

[pepe]

I would hazard a guess that only 0.1% of DR shops have a lab supply.

you have very bad oppinion about DR companies, but we knew that Numbers are not that bad i think. (I have 3 just to make them nicer
I do think he has one, but let's see.
Polyswitch is ok of course, if you have one handy, but you still need to source 3.3V from somewhere...
Btw, i haven't ever seen a PSU that has 3.3V on SATA power connector, which does not mean they do not exist, just they are not frequent. I think there are more Lab supplies in DR companies than such pc PSUs.

[pepe]

hm, i stand corrected, i have one such PSU.
pepe

[digisupport]

Would not last a day here without my lab supply

[Lardman]

hm, i stand corrected, i have one such PSU.

All my Dell WS have it

:lol: Would not last a day here without my lab supply

It's a good point though, I suspect those who don't do flash recovery haven't seen much need, I just had a old PSU on the bench for a long time.

[pepe]

yes, now i checked another PC and it has it too, just never noticed.
:s

[suricate.ch]

Hi,

I was at customer site whole day. I'll try tomorrow morning. Thank you so much for your help and your patience.

Thanks

[fzabkar]

I would hazard a guess that only 0.1% of DR shops have a lab supply.

you have very bad oppinion about DR companies, but we knew that :) Numbers are not that bad i think. (I have 3 just to make them nicer :)
I do think he has one, but let's see.
Polyswitch is ok of course, if you have one handy, but you still need to source 3.3V from somewhere...
Btw, i haven't ever seen a PSU that has 3.3V on SATA power connector, which does not mean they do not exist, just they are not frequent. I think there are more Lab supplies in DR companies than such pc PSUs.

The first post in this thread is typical of DR companies. Clearly the OP has no real experience in electronic troubleshooting. If the customer has reported an overvoltage event, then you start with the protection devices and power supplies. I have written detailed tutorials on the subject, and have also provided a quick-and-dirty explanation, yet people still don't get it, even after hundreds of posts. What use is a lab PSU to people who have no basic understanding, other than to impress clients? You and I can locate the power supplies on unfamiliar PCBs in a matter of seconds by visual inspection. It's not that hard, is it?

I would suggest that people spend some time and learn about the subject. They owe it to their customers. Louis Rossman has written a primer on electronic troubleshooting. That would be a good start.

As for PSUs with 3.3V on the SATA cable, I see them all the time in the user forums. People are often reporting that a new drive drive won't spin up. That's because there is 3.3V on the Power Disable pin.