QFN Dead Bug - Page 1
Forum section: electronics / general

author: @rt
author_rank: Super Contributor
timestamp: April 12, 2019, 06:28:23 am
content: That was fun

author: capt bullshot
author_rank: Super Contributor
timestamp: April 12, 2019, 06:48:37 am
content: Ouch

author: OwO
author_rank: Super Contributor
timestamp: April 12, 2019, 07:20:34 am
content: What's wrong with just getting a breakout board

author: Berni
author_rank: Super Contributor
timestamp: April 12, 2019, 07:42:50 am
content: Yep i have done it before and it can get very annoying with the tiny pin pitch ones.Sometimes you don't have a breakout board on hand but really want to test out a chip this moment.

author: harnon
author_rank: Regular Contributor
timestamp: April 12, 2019, 07:44:24 am
content: I've always wondered how to do star grounding.

author: @rt
author_rank: Super Contributor
timestamp: April 12, 2019, 09:22:40 am
content: It’s an oddball. I’m not sure there is a breakout PCB for it.

author: Psi
author_rank: Super Contributor
timestamp: April 12, 2019, 09:25:47 am
content: Someone had to do it....

author: capt bullshot
author_rank: Super Contributor
timestamp: April 12, 2019, 09:41:17 am
content: Double^h^h^h^h^h^hthousandfold ouch

author: @rt
author_rank: Super Contributor
timestamp: April 12, 2019, 09:52:52 am
content: Have seen. Interesting way to address faulty BGA process.This one from 2 years ago still going strong.It got a blob of potting compound shortly after this pic was taken.

author: JPortici
author_rank: Super Contributor
timestamp: April 12, 2019, 10:09:17 am
content: Quote from: @rt on April 12, 2019, 09:22:40 amfucking sillabs. the guy who though and approved of this should be flayed.(I assume it's sillab as i had to prototype a RF transceiver with that same package. And obviously the pads underneath carry essential signals)

author: @rt
author_rank: Super Contributor
timestamp: April 12, 2019, 10:52:58 am
content: I don’t know what you call it, but even if breakout was available, I wouldn’t have waited the 1-2 weeks for it.

author: @rt
author_rank: Super Contributor
timestamp: April 12, 2019, 12:00:27 pm
content: The damn thing works! .. which is cool because it took hours.

author: Psi
author_rank: Super Contributor
timestamp: April 12, 2019, 12:01:12 pm
content: Quote from: @rt on April 12, 2019, 12:00:27 pmWas that with or without a microscope?

author: @rt
author_rank: Super Contributor
timestamp: April 12, 2019, 12:29:58 pm
content: I’m just a scumbag with a bifocal magnifying glass.

author: @rt
author_rank: Super Contributor
timestamp: April 12, 2019, 12:30:45 pm
content: from our good friends at Jaycar Electronics.

author: jonovid
author_rank: Super Contributor
timestamp: April 12, 2019, 12:48:41 pm
content: Quote from: Psi on April 12, 2019, 09:25:47 amtop marks!

author: Psi
author_rank: Super Contributor
timestamp: April 12, 2019, 01:02:24 pm
content: Wasn't me, just someone had to post that old pic in this thread

author: PA0PBZ
author_rank: Super Contributor
timestamp: April 12, 2019, 02:22:18 pm
content: Quote from: Psi on April 12, 2019, 01:02:24 pmNow you made me post this:

author: Canis Dirus Leidy
author_rank: Regular Contributor
timestamp: April 12, 2019, 03:36:47 pm
content: Japanese don't surrender!

author: @rt
author_rank: Super Contributor
timestamp: April 12, 2019, 04:43:39 pm
content: To be honest, with the right tools, I don’t see any difficulty in that last one at all, except maybe that NAND or whatever it is.

author: JPortici
author_rank: Super Contributor
timestamp: April 12, 2019, 06:08:12 pm
content: Yeah, more tedious than difficult

author: Berni
author_rank: Super Contributor
timestamp: April 12, 2019, 06:17:55 pm
content: Quote from: Canis Dirus Leidy on April 12, 2019, 03:36:47 pmIm guessing thats Elm Chans work. One of the few people that builds circuits like that and somehow makes it look so neat and tidy at the same time.

author: james_s
author_rank: Super Contributor
timestamp: April 13, 2019, 12:29:27 am
content: Elm Chan has astonished me for years, his work is absolutely amazing, I've built a lot of stuff by hand but I can't touch his level of neatness.

author: ElectronicSupersonic
author_rank: Regular Contributor
timestamp: April 14, 2019, 03:50:59 am
content: Although far less impressive, here are few pics of my attempt at recovering EMMC from Samsung tablet.

author: Berni
author_rank: Super Contributor
timestamp: April 14, 2019, 07:26:25 am
content: Ah yes i already recognize its a eMMC from that damn evil footprint.Difficult to even solder on a PCB. So many tiny pitch balls, yet 90% of them are just NC. Why not just use a damn QFN if you only need 10 pins.

author: @rt
author_rank: Super Contributor
timestamp: April 14, 2019, 08:23:43 am
content: Quote from: Berni on April 14, 2019, 07:26:25 amI assume that was for data retrieval.

author: PA0PBZ
author_rank: Super Contributor
timestamp: April 14, 2019, 09:21:27 am
content: Quote from: @rt on April 14, 2019, 08:23:43 amI assume that comment was for the manufacturer.

author: @rt
author_rank: Super Contributor
timestamp: April 14, 2019, 09:50:50 am
content: Ah, well most pins won’t be connected, but neither will Samsung be using JTAG or SPI interfaces with their own chip in their own consumer device.At least I hope not, these should have 8 bit or 4 bit interface as well.

author: Berni
author_rank: Super Contributor
timestamp: April 14, 2019, 12:32:49 pm
content: Yeah that was aimed at the manufacturers of eMMC.The pin out of the thing is ridiculous. Not only have they used a package with 10 times more pins than they needed, used an unnecessarily tiny ball pitch that makes it a pain in the ass to solder, but the pins are not even arranged in a pattern that would be easy to fan out. A brain dead monkey randomly plonking down pins would create a better pinout than this.At least for data recovery he only needed Vcc Ground Clock Command Data0.

author: ElectronicSupersonic
author_rank: Regular Contributor
timestamp: April 14, 2019, 05:08:20 pm
content: @ @rtQuoteThe intention was to revive it, not so much as to use it, but rather to learn something new (a challenge to myself if you will). Unfortunately it wasn't a success story. Usually then such eMMC failure occurs, it can be "revived" with USB SD card reader, or if things are bad enough with PCI-E SD card reader (at least by the info I've found online). USB SD card stage was somewhat successful, but the tablet didn't work in the end. That can easily be my "top notch" BGA soldering skills though.Decided to proceed to PCI-E stage. A PCI-E card reader was needed and there was one in my notebook, but it had few pins bent and wasn't working. Attempted to fix it, but construction of the reader was such that one had to destroy it to fix it. In an attempt to replace the reader, the motherboard died (it was on its last leg anyway).The end result is a dead Samsung tablet (i.e. not fixed), a dead notebook and new (well a used one) notebook which I had to repair (corrupt BIOS) for which I had to make an SPI programmer and to debug an issue of BIOS not updating ("dirty" ME region problem).Bottom line, one can never know/predict how things may develop and what one can end up learning.