Samsung 960 Pro 1TB NVME - Page 1
Forum section: electronics / repair

author: kahuna0k
author_rank: Regular Contributor
timestamp: May 07, 2019, 10:10:07 am
content: I'm trying to replace the SMD "thing" marked with a red circle in the attached image (is another drive, same model). It seems that I hit it with something when building a desktop with old parts and it just got lost. Right now the NVME drive is not even detected, maybe there are more things damaged by that missing resistor but I'll try the obvious thing and if not forget about itWith an LCR meter the two below it seem to be resistors, the meter starts metering 40K and decrease down to 27K. I'm planning to desolder one of the two and measure it isolated. I don't know for sure if they are the same, but the thing is not going to be covered by the warranty, so that's my only opportunity. Any clue on how to figure the actual component that goes there? Trying to find the schematics for the drive has proven _hard_.

author: wraper
author_rank: Unknown
timestamp: May 07, 2019, 10:25:07 am
content: MLCC ceramic capacitor. Should have the same capacitance as nearby cap. You can desolder and measure that.

author: ataradov
author_rank: Super Contributor
timestamp: May 07, 2019, 06:24:40 pm
content: Missing capacitors are not very likely to result in a completely dead unit. There is probably something else is wrong with it.

author: DaJMasta
author_rank: Super Contributor
timestamp: May 07, 2019, 06:29:49 pm
content: Any high resolution photos of the module available in a review or something? Could give you an idea. If you have an inspection scope or a jeweler's loupe, it's probably worth investigating the pads around it too to see if anything else was damaged and to confirm that specific one was the missing one.If it is, that's what, an 0402 size? Doable by hand, but you're going to want some magnification to inspect it, at least. Could be a decoupling cap or something, but as mentioned, generally there's more tolerance for that sort of thing and missing one wouldn't immediately brick it.

author: Jeroen3
author_rank: Super Contributor
timestamp: May 07, 2019, 07:59:31 pm
content: Quote from: ataradov on May 07, 2019, 06:24:40 pmMissing inductors do. And those are also available in that form factor.

author: kahuna0k
author_rank: Regular Contributor
timestamp: May 08, 2019, 07:02:51 am
content: I don't have a way to take pictures through the AmScope I use to solder, I've attached the best macro I've been able to take of the zone after desoldering another component, trying to measure it outside the circuit. I'm using the LCR Pro1 SmartTweezers, and they are unable to identify the piece in Auto. Outside the circuit I get the same behavior that in-circuit. The tweezers in A will show a variable resistance oscillating from 100Ohm to 50 mOhm, depending on the frequency. Forcing the mode to L I get around 100nH (this could also fit Jeroen3 comment about inductors being more critical). Now I need to wait for a 0402 inductors kit to arrive, I have resistors and capacitors in 0402, but inductors ... yes you always lack what you need.

author: wraper
author_rank: Unknown
timestamp: May 08, 2019, 11:24:58 am
content: That's a ferrite bead. You should not use inductors there. They have too small current rating and too big resistance for the size and not that good for such use to begin with. In your first picture it did not appear black so I thought it was MLCC.

author: Miti
author_rank: Super Contributor
timestamp: May 08, 2019, 02:25:55 pm
content: Try a solder blob instead of the ferrite bead to validate that you're on the right path. If it is detected, you can install a proper ferrite bead later. If not, well, you may need another drive.

author: kahuna0k
author_rank: Regular Contributor
timestamp: May 08, 2019, 05:09:38 pm
content: How can I characterize the ferrite bead? I mean how can I know what I need to buy if I want to replace it with exactly the same piece? Should I measure the DC resistance and resistance at 100Mhz? These are the parameters I see at digikey, but I understand that the band of frequencies attenuated is not just 100Mhz and could be something completely different. Should I characterize it as a RF filter with a tracking generator and a spectrum analyzer? First time dealing with SMT ferrite bead.Thank you all for the good info.

author: DaJMasta
author_rank: Super Contributor
timestamp: May 08, 2019, 05:20:06 pm
content: DCR won't give you a lot of information, it's going to depend mostly on the ferrite material used, which is never marked and could be difficult to just guess. The right way to find out would be to measure impedance at 10/25/100MHz or thereabouts, then look through datasheets for ferrite material type impedance graphs and just try a best-fit. Given the tiny size, though, even the most permeable ferrite material is going to do only a tiny amount. I would find a suitably sized middle-of-the-road ferrite and just stick it in.That said, it's probably worth looking up any application notes for the NVME interface or comparable flash memories (probably behind NDAs, in that case) and seeing what ferrites they use. Could give you a better match for what it's used in. Given the size, I would assume it's on a signal line and not just trying to take the edge off a power supply rail, so it's meant to filter a little bit extra of the fast transients, but probably has to pass some decent bandwidth through it without significant losses.

author: kahuna0k
author_rank: Regular Contributor
timestamp: May 09, 2019, 06:29:41 am
content: Well, at the end I found that one thing is desoldering a 0402 and another very different soldering it back. I've done 0603 without much problems, but 0402 is clearly beyond my skill ... I suppose I will be much more careful when handling exposed electronics inside a computer ... too many years doing it and you loose any respect :/

author: pix3l
author_rank: Regular Contributor
timestamp: May 09, 2019, 06:56:31 am
content: With some hot air, flux and tweezers it's not too hard ;-)

author: Jeroen3
author_rank: Super Contributor
timestamp: May 09, 2019, 10:03:07 am
content: When it's small, add more flux. Let the surface tension do the work.

author: beepl4n
author_rank: Newbie
timestamp: May 09, 2019, 01:18:32 pm
content: Don´t exaggerate guys, even 0201 can be reworked with a normal soldering iron. Fine tip and tweezers, some flux and go for it!You have a change to find the value and type of missing component, if you can read the part number for the small chip near it (probably a voltage regulator) and try to find its datasheet and application circuit.But at first look i also agree it has a good chance to be a ferrite bead.Good luck!

author: EOC_Jason
author_rank: Contributor
timestamp: May 09, 2019, 05:53:54 pm
content: That SSD is only about a year old... It has a 5 year warranty... That seems about the easiest route, unless there is some critical data on there that you don't have backed up...

author: maginnovision
author_rank: Super Contributor
timestamp: May 09, 2019, 06:43:22 pm
content: Quote from: EOC_Jason on May 09, 2019, 05:53:54 pmI don't think they're going to cover damage by user. I hope not anyway. Good way to ruin your business.

author: kahuna0k
author_rank: Regular Contributor
timestamp: May 10, 2019, 08:42:58 pm
content: Well at the end soldering 0402 blobs was doableIt works!!! just replacing both ferrite beads (the one I damaged and the one I removed) with blobs and the drive is recognized and I still have the data there. Pretty amazing. I will run some benchmarks and checksums to see how the lack of those ferrite beads affect signal integrity.As I side note, these drives are designed to dissipate heat efficiently what makes soldering those components extra hard, as the left pad seems to be connected to a ground plane that probably is also connected to the integrated heatsink in the back.I will struggle with the 0402 form factor once the new ones arrived, but for now I'm super happy, first time this hobby saves me money instead of eating it

author: wraper
author_rank: Unknown
timestamp: May 10, 2019, 08:46:57 pm
content: Quote from: kahuna0k on May 10, 2019, 08:42:58 pmUseless waste of time. It will just work. What checksums when controller does error correction. Reliability might be reduced though.

author: Rasz
author_rank: Super Contributor
timestamp: May 10, 2019, 11:44:08 pm
content: Quote from: kahuna0k on May 10, 2019, 08:42:58 pmthats why preheating is a thing, makes life a lot easier on multilayer boards. Knowing the limits of materials also helps, sometimes its worth to find a similar/same model broken unit just to learn how it reacts/train on it with hot air in advance. Nothing worse than doing something requiring super precision on $$$ stuff for the first time.

author: Miti
author_rank: Super Contributor
timestamp: May 11, 2019, 01:00:31 pm
content: Quote from: kahuna0k on May 10, 2019, 08:42:58 pmRead my post above. I tooold ya...If I were you, I would completely forget about the ferrite beads. Most likely they are there for some very subtle EMI tests to pass and have nothing to do with data integrity or reliability. Your drive will live happily ever after, longer than Samsung says it will.