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 Post subject: Re: Samsung 840 EVO 512GB - burned - pls need advice
PostPosted: June 27th, 2015, 4:58 
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Joined: June 25th, 2015, 16:16
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Location: Czech Republic
Hello,

great investigation, thank you!
Its seems to be the right IC. And is orderable via ebay and Mouser.
The pad under is really grounded, pin 5 is ground, but on SSD PCB is not connected, because IC is grounded via large pad - and pin 5 - as is in datasheet - is internally grounded.
Pin 6 is really grounded via cap on ssd PCB, so it is OK too.
Pin 7 - EN - is connected to 5V input on second side of the PCB, see photo, so its enabled right by 5V sata voltage.
Dimension are same, 3x3 mm
5A seems odd ... dont know ...


And yes, 5V Guill input is connected to 5V output of ther burned JS4NAM
C1 and C2 are OK, not shorted, resistance in MOhms, C1 has 63μF and C2 128μF.
I measured all caps on both sides, quick test, seems to be no short.

Attachment:
PCB2.jpg
PCB2.jpg [ 655.36 KiB | Viewed 4526 times ]


Thx

Daniel


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 Post subject: Re: Samsung 840 EVO 512GB - burned - pls need advice
PostPosted: June 27th, 2015, 15:04 
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Joined: September 8th, 2009, 18:21
Posts: 11990
Location: Australia
If pin 5 is connected to the IC's pad, then you should have measured a short between pin 5 and PCB ground when the IC was installed on the PCB. But you stated that there was no ground connection to any IC pin. BTW, Farnell and Digikey also have the STEF4S IC ($3).

As for the 5A rating, the datasheet does in fact specify that this IC is targeted at SSD applications. Otherwise, could it be that Samsung's IC is a special order with OEM specs?

ISTM that the GUILL IC and its load are probably OK. You could confirm whether this buck regulator supplies the NAND array by testing for continuity between its output and the ceramic Vcc bypass capacitors adjacent to any of the NANDs.

The AKE4JR chip appears to comprise 5 buck regulators and some other circuitry which I don't recognise. I suspect that these regulators would provide Vcore and Vio for the flash controller (S4LN045X01-8030), plus the Vcc for the SDRAM (K4P4G324EQ-FGC2).

You could confirm that no regulator output is shorted to ground by testing the resistances of C1 - C5. L1 - L5 are the corresponding inductors.

I don't understand the function of the area consisting of L6 (?), C6A, C6B, and X. It might be worth checking whether any of these components are connected to ground or 5Vout. If X is a diode, then it could be that this circuit constitutes a boost regulator, but I can't understand what this would do.


Attachments:
Big_Reg.jpg
Big_Reg.jpg [ 160.08 KiB | Viewed 4503 times ]

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 Post subject: Re: Samsung 840 EVO 512GB - burned - pls need advice
PostPosted: June 27th, 2015, 15:32 
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Joined: June 25th, 2015, 16:16
Posts: 23
Location: Czech Republic
Any of pins PCB is grounded, only pad. Pin 5 on PCB is connected anywhere ( blind - dont know the right idiom - my English isnt good ) And in datasheet is : "5 GND Ground pin (can be left floating if TAB is connected to GND)" - so its OK.

And first page of datasheet :
Applications
• Hard disk drives
• Solid state drives (SSD)
• Hard disk and SSD arrays
• Set-top boxes
• DVD and blu-ray disc drivers
:)

I just order 2pcs on Farnell, try to find another replacement and only this one has the right pinout.
Maybe same IC, but only OEM version for Samsung Corp.
Measurements tomorrow, today I am very tired and must sleep.

Thx master :good:

Daniel


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 Post subject: Re: Samsung 840 EVO 512GB - burned - pls need advice
PostPosted: June 28th, 2015, 5:54 
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Joined: August 15th, 2006, 3:01
Posts: 2693
Location: CDRLabs @ Chandigarh [ India ]
danikd wrote:
Hello,

great investigation, thank you!
Its seems to be the right IC. And is orderable via ebay and Mouser.
The pad under is really grounded, pin 5 is ground, but on SSD PCB is not connected, because IC is grounded via large pad - and pin 5 - as is in datasheet - is internally grounded.
Pin 6 is really grounded via cap on ssd PCB, so it is OK too.
Pin 7 - EN - is connected to 5V input on second side of the PCB, see photo, so its enabled right by 5V sata voltage.
Dimension are same, 3x3 mm
5A seems odd ... dont know ...


And yes, 5V Guill input is connected to 5V output of ther burned JS4NAM
C1 and C2 are OK, not shorted, resistance in MOhms, C1 has 63μF and C2 128μF.
I measured all caps on both sides, quick test, seems to be no short.

Attachment:
PCB2.jpg


Thx

Daniel


Well,
I am Happy To Know The Ground Was As I Stated .But Frank did a Greater Job Then Me In Assisting You .The Caps You See Are Connected To Vin I think On One Side .If This Works Please Let Us All Know So That Someone Gets Assistance In Future In Similiar Cases

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Amarbir S Dhillon , Chandigarh Data Recovery Labs
Logical,Semi Physical And Physical Data Recovery
Website-> http://www.chandigarhdatarecovery.com


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 Post subject: Re: Samsung 840 EVO 512GB - burned - pls need advice
PostPosted: June 28th, 2015, 15:26 
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Amarbir, I have no idea what you are banging on about.

The location of ground is abundantly clear. I have always understood that the pad under the IC is grounded and I have identified it as "0V" in the photo clip. I did not need to ask the OP to verify this connection -- you did.

fzabkar wrote:
As for the grounded underside of the package ...

What has not been clear is whether the pad has an electrical connection to the IC or merely a thermal connection. It now appears that the pad performs both functions.

What is still not clear is why the OP's in-circuit measurements did not show continuity between the IC's pin 5 and ground. If the IC is an STEF4S, then pin 5 would be internally connected to the IC's pad, which is then grounded by the PCB. However, the OP indicated that "no pin [is] shorted to ground", so this is why I am questioning whether the IC is in fact and STEF4S.

That said, I am confident that an STEF4S will function as a replacement, although I'm wondering about the 5A trip current rating.

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 Post subject: Re: Samsung 840 EVO 512GB - burned - pls need advice
PostPosted: June 29th, 2015, 14:11 
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Joined: June 25th, 2015, 16:16
Posts: 23
Location: Czech Republic
Hello,

sorry no measurement yet, no time :( Tommorow replacement will arrive from Farnell, i try it and let you know. Thx. Daniel


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 Post subject: Re: Samsung 840 EVO 512GB - burned - pls need advice
PostPosted: June 29th, 2015, 14:45 
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Joined: September 8th, 2009, 18:21
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Location: Australia
I notice that the 850 Evo 500GB has an unpopulated electronic fuse and a 5V TVS diode. The 5Vin and 5Vout are bridged with two components.

http://www.thessdreview.com/our-reviews ... lc-v-nand/
http://tssdrcdn.thessdreview1.netdna-cd ... B-Back.jpg


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5V_TVS_diode.jpg
5V_TVS_diode.jpg [ 12.87 KiB | Viewed 4416 times ]
e-fuse.jpg
e-fuse.jpg [ 32.7 KiB | Viewed 4416 times ]

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 Post subject: Re: Samsung 840 EVO 512GB - burned - pls need advice
PostPosted: June 30th, 2015, 16:03 
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Joined: June 25th, 2015, 16:16
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Location: Czech Republic
Hello!

replaced with STEF4S and its working!!! So many thanx to all, especialy to fzabkar, you are really master!
Hope it will help to someone in future ...
Nice day to all!

Daniel


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 Post subject: Re: Samsung 840 EVO 512GB - burned - pls need advice
PostPosted: June 30th, 2015, 16:52 
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Congratulations. BTW, what are the markings on the STEF4S chip?

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 Post subject: Re: Samsung 840 EVO 512GB - burned - pls need advice
PostPosted: July 1st, 2015, 9:45 
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Joined: June 25th, 2015, 16:16
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Location: Czech Republic
Heelo, see photo. Nice day. Daniel


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 Post subject: Re: Samsung 840 EVO 512GB - burned - pls need advice
PostPosted: July 4th, 2015, 15:48 
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Joined: September 8th, 2009, 18:21
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Thanks. I wish I had your soldering skill.

BTW I'm now seeing e-fuses everywhere.

Here is an example from an Intel S3700:
Attachment:
e-fuses.jpg
e-fuses.jpg [ 198.25 KiB | Viewed 4310 times ]

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 Post subject: Re: Samsung 840 EVO 512GB - burned - pls need advice
PostPosted: July 10th, 2015, 15:37 
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Joined: June 25th, 2015, 16:16
Posts: 23
Location: Czech Republic
Hello

I thanks, wish I had your knowledge ...
Monday, maybe I will post another SSD problem, with Vertex 2. Solid green, but even after 200 restarts and connections, no detection ... I will start new thread.

Nice weekend.

Daniel


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 Post subject: Re: Samsung 840 EVO 512GB - burned - pls need advice
PostPosted: August 28th, 2015, 4:33 
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Joined: August 28th, 2015, 4:31
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Location: italy
could you kindly confirm that the component is this one? thanks

http://uk.farnell.com/webapp/wcs/stores ... reId=10165


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 Post subject: Re: Samsung 840 EVO 512GB - burned - pls need advice
PostPosted: August 28th, 2015, 6:45 
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Joined: June 25th, 2015, 16:16
Posts: 23
Location: Czech Republic
Hello, yes, the right one ... Daniel


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