Author Topic: QFN Dead Bug  (Read 1743 times)

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Offline blueskull

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Re: QFN Dead Bug
« Reply #25 on: April 14, 2019, 07:31:27 am »
EFM8 or CP210N?
 

Offline @rt

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Re: QFN Dead Bug
« Reply #26 on: April 14, 2019, 08:23:43 am »
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.

I assume that was for data retrieval.
 

Online PA0PBZ

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Re: QFN Dead Bug
« Reply #27 on: April 14, 2019, 09:21:27 am »
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.

I assume that was for data retrieval.

I assume that comment was for the manufacturer.
Keyboard error: Press F1 to continue.
 

Offline @rt

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Re: QFN Dead Bug
« Reply #28 on: April 14, 2019, 09:50:50 am »
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.
 

Online Berni

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Re: QFN Dead Bug
« Reply #29 on: April 14, 2019, 12:32:49 pm »
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.
 

Offline ElectronicSupersonic

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Re: QFN Dead Bug
« Reply #30 on: April 14, 2019, 05:08:20 pm »
@  @rt
Quote
I assume that was for data retrieval.
The 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.  :)
« Last Edit: April 14, 2019, 05:59:53 pm by ElectronicSupersonic »
 


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