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Samsung 840 EVO 512GB - burned - pls need advice

June 25th, 2015, 16:42

Hello to all, my 1st post.

Can you please help me with burned Samsung 840 EVO 512GB.
It has burned some 10 pin chip, first in 5V way. Marked JS4NAM, but can find nothing about it.
Its square, about 5mmx5mm, height about 1mm ... 5 pins on both side.
See photo.
Maybe some diode block?
Thx for info.

Daniel
Attachments
IMG_20150625_162222.jpg
IMG_20150625_162146_1.jpg

Re: Samsung 840 EVO 512GB - burned - pls need advice

June 25th, 2015, 17:46

I suspect that the component could be bypassed with a wire link, but we need to take some measurements first.

What is the resistance between the 5V pins and ground?

What is the resistance between ground and the group of 3 pins on the other side of the IC?

What is the resistance between the group of 3 pins and the 5V pins?

Which of the IC's other pins are grounded?

Re: Samsung 840 EVO 512GB - burned - pls need advice

June 26th, 2015, 4:01

Hello,

Thx for your help. I measure it - see photo diagram.
I add another 2 photos with IC, from USB microscope.
Have a nice day and thank you.

Daniel
Attachments
PCB.jpg
IC1.jpg
IC.jpg

Re: Samsung 840 EVO 512GB - burned - pls need advice

June 26th, 2015, 4:22

I have replaced these before, it's quite a straight froward procedure. But TBH, you really need to find out why this has blown before you replace it, and whether the failure has been caused power side or drive side....

Would really not recommend 'bridging' it with wires until the facts of how it occurred in the first place are known. Having said that, I have just replaced these in the past and the drive worked fine afterwards with no other components seemingly affected....

Good luck... :)

Re: Samsung 840 EVO 512GB - burned - pls need advice

June 26th, 2015, 4:36

Touchclarity wrote:I have replaced these before, it's quite a straight froward procedure. But TBH, you really need to find out why this has blown before you replace it, and whether the failure has been caused power side or drive side....

Would really not recommend 'bridging' it with wires until the facts of how it occurred in the first place are known. Having said that, I have just replaced these in the past and the drive worked fine afterwards with no other components seemingly affected....

Good luck... :)

Thanks for the input. Do you know what the device actually is? I thought it may have been a power switch of some kind, but that would require some kind of control signal, or at least a connection to ground. If it's just a switch, then it would be OK to run a wire link (or fuse) between the two pads alongside the IC, provided that there was no short circuit on the load side, as appears to be the case. In fact ISTM that the PCB's designer gave the factory the option of either installing the link (zero-ohm resistor?) or the JS4 protection (?) device. Alternatively, I was thinking that the component may be a PolyZen, or similar, but that would require a ground pin.

Re: Samsung 840 EVO 512GB - burned - pls need advice

June 26th, 2015, 8:26

Touchclarity wrote:I have replaced these before, it's quite a straight froward procedure. But TBH, you really need to find out why this has blown before you replace it, and whether the failure has been caused power side or drive side....

Would really not recommend 'bridging' it with wires until the facts of how it occurred in the first place are known. Having said that, I have just replaced these in the past and the drive worked fine afterwards with no other components seemingly affected....

Good luck... :)


Many thx to you experts,

SSD history is unknown, but now is mine, my PSU and MB is 100% OK. But you know, what if ...
Touchclarity, pls what replacement part I must buy and pls where ... ALI, ebay, no problem ...
Fzabkar, polyzen, as I read, really use ground pin, I can desolder burned IC and post photo of PCB under ...
Nice day!

Daniel

Re: Samsung 840 EVO 512GB - burned - pls need advice

June 26th, 2015, 8:48

you could also try and buy a secondhand SSD from ebay and canabalise the part.
I have an evo here, I will rip it open when I return home from a very unwanted late night ice cream run .. grr..
(I think it is a secret coup to get me off the computer)

Re: Samsung 840 EVO 512GB - burned - pls need advice

June 26th, 2015, 9:41

SSD from ebay are very expensive, even in "for parts" state.
If I cant find replacement part, I will try wire bridging.
Pls see photos with unsoldered IC.
Can anyone advice which pins to wire? Ideal colour lines in Windows paint.
Next fot is from 850Pro ( from web ) - same part but only first 3 leters JS4 are same
Anyone any clue where to buy it? Or some replacement ?
Thx.

Daniel

PS: HaQue, happy ice cream run :) Thx for any info and advice.
Attachments
850Pro.jpg
Unsoldered.jpg

Re: Samsung 840 EVO 512GB - burned - pls need advice

June 26th, 2015, 10:44

Well,
Why did You Remove The Capacitor .Also The Bottom Of This Definately Has Voltage IMHO As There Are Capacitors Bridged To Ground From There .

Re: Samsung 840 EVO 512GB - burned - pls need advice

June 26th, 2015, 11:06

"JS4" is probably the part number. The remaining characters are probably the date or batch code. FWIW I have seen "JS3F A" on other similar Samsung PCBs.

Re: Samsung 840 EVO 512GB - burned - pls need advice

June 26th, 2015, 11:24

Amarbir wrote:Well,
Why did You Remove The Capacitor .Also The Bottom Of This Definately Has Voltage IMHO As There Are Capacitors Bridged To Ground From There .

Which CaPaCiToR are you talking about?

Re: Samsung 840 EVO 512GB - burned - pls need advice

June 26th, 2015, 11:38

fzabkar wrote:
Amarbir wrote:Well,
Why did You Remove The Capacitor .Also The Bottom Of This Definately Has Voltage IMHO As There Are Capacitors Bridged To Ground From There .

Which CaPaCiToR are you talking about?


Frank ,
I Was Refering To The Image That He Has Got Off The Net .But i See Thats Not There In The Patient He Has . Can You Please Check If The Bottom Is Short To Ground " danikd " .

PS : danikd Can You Please Check The Bottom Of The IC To Ground .IMHO IT Should Be Ground Not Voltage As i Ref To Earlier .

Re: Samsung 840 EVO 512GB - burned - pls need advice

June 26th, 2015, 11:59

The chip on my EVO 128GB is FN4MAJ

Re: Samsung 840 EVO 512GB - burned - pls need advice

June 26th, 2015, 13:53

HEllo, tomorrow I will check the PCB, the if the under the IC is ground. I let you know. Anyone from you professionals can sell the IC - have broken Samsung SSD ? Thx for help. Daniel

Re: Samsung 840 EVO 512GB - burned - pls need advice

June 26th, 2015, 16:05

HaQue wrote:The chip on my EVO 128GB is FN4MAJ

Could the "4" be part of the date code, ie 2014? That seems to fit with the JS3 and JS4 examples that I have found.

As for the grounded underside of the package, I would expect that it is intended for heat dissipation and would have no electrical connection to the chip's die. Perhaps this chip is different?

Would you be able to measure the voltage on the output side of this chip? I expect that it would be 5V, ie the same as the input side.

Re: Samsung 840 EVO 512GB - burned - pls need advice

June 26th, 2015, 16:29

I'm guessing that the circuit could be bridged as follows:
Unpopulated_fuse.jpg


A 1A polyswitch (resettable fuse) might be a good choice. These can be scavenged from around the USB ports of old motherboards. It would be a good idea to take some additional measurements around the two regulators (AKE4JR and GUILL). We would need to see the underside of the PCB, though.

Re: Samsung 840 EVO 512GB - burned - pls need advice

June 26th, 2015, 16:49

Here is a typical motherboard polyswitch (for USB, PS/2 keyboard):

http://media.digikey.com/photos/Tyco%20 ... SERIES.jpg

Re: Samsung 840 EVO 512GB - burned - pls need advice

June 26th, 2015, 17:03

I suspect that the "GUILL" chip is responsible for the 3.3V supply to the NAND array.

Can you confirm whether the 5V input is connected to the "5V out" of the JS4NAM chip?

Can you measure the resistances across capacitors C1 and C2? This will tell us whether there is a short circuit on the load side of the chip.

The underside of the PCB would have several more supply rails, and the same tests would need to be done for each of those.
Attachments
3V3_reg.jpg
3V3_reg.jpg (49.09 KiB) Viewed 11706 times

Re: Samsung 840 EVO 512GB - burned - pls need advice

June 27th, 2015, 1:05

fzabkar wrote:
HaQue wrote:The chip on my EVO 128GB is FN4MAJ

Could the "4" be part of the date code, ie 2014? That seems to fit with the JS3 and JS4 examples that I have found.

As for the grounded underside of the package, I would expect that it is intended for heat dissipation and would have no electrical connection to the chip's die. Perhaps this chip is different?

Would you be able to measure the voltage on the output side of this chip? I expect that it would be 5V, ie the same as the input side.


Well,
In This Case It Seems Ground As You Can Clearly Seem Capacitors Connected To The Same .I HaVe NeVer SeEm CaPaCiToRs CoNnEcTeD HeAt Source Lol

Re: Samsung 840 EVO 512GB - burned - pls need advice

June 27th, 2015, 2:34

The mystery part looks very much like this electronic fuse, except for pin 5:

STEF4S, STMicroelectronics, Electronic fuse for 3.3 V and 5 V lines, Output clamp voltage 5.7V in 5V mode, Protection trip current 5A:
http://www.st.com/web/en/resource/techn ... 095426.pdf

The EN-able pin (7) is probably tied to VIN (5V) by the external circuit.

The trip current rating of 5A seems much too high for an SSD that would probably draw less than 0.5A.
Attachments
STEF4S.jpg
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