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It has been about a week since I booted into my Raspberry Pi.

This evening when I booted it, raspberrypi.local could not be detected on the network.

However the card was burning burning hot

I plugged SD card into different USB drives on both computers at home and it could not be detected.

I saw similar question on SE (cannot find link now) and the solution was to replace the SD card and use SD card from reputable company

My SanDisk Ultra SD Card was purchased from Amazon exactly a year ago.

Before I purchase a pack of SD Cards, please recommend most reputed SD Card for Raspberry Pi

Here is the one I purchased a year back

enter image description here

Marium
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1 Answers1

2

the SD card was burning burning hot

Question

Why my SD Card gets hot?

Short Answer

Because somewhere in the electronics circuit inside the card is shorted, causing a big current flowing, heating up things, therefore burning hot.

Long Answer

Literature Search

I googled forums for 5 minutes, but found wasting my time. :(

Example forum discussion on burning hot SD Card problem

So I googled schematics, and found the following looking good. :)

rpi model b sd card

SD Card Death Rate

I counted the micro SD acrds I have been using for 4 years (Rpi 2/3 since 2015) , and found the following statistics:

Good = 21

Bad = 4

In other words, the bad probability for a Rpi hobbyist is

(4 / (21 + 4)) = 16%

And bad cards per year is

4 / 5 = 0.8 ~= 1 bad card / yr.

bad micro SD cards

Bad rate of SD card makers

I counted the non SanDisk cards and found I used 3 Kingston cards, and 1 Toshiba. So the ridiculously small sample size lying statistics is:

Bad SD Card Maker Statistics

Toshiba ~= 0%

SanDisk = (4 - 1）/ 24 ~= 13%

Kingston ~= 33%

Postmortem

Now I am going to use my cheap cheap multi-meter to do open/short resistance check to make a quick and dirty conclusion of why they were burnt to death.

Update 2019apr21hkt2219

I did not find any of the bad cards short circuited somewhere. So I guess they are burning hot not because of short circuited current causing heating up. To investigate further, I decided to buy a couple of new SD cards and see if copying Raspbian image also causes heating up.

sd card pinout

I copied the Raspbian 2019Apr image to four cards, as described by the picture below.

copying image causing heating up

sd card adapter

I also watched the following video to see what is inside the card. I found it too complicated for me to dig deeper. So I just make some conclusion and guideline for myself and other hobbyist programming newbies like me.

Inside the SD Card - Data recovery of 'burnt' card - PITS 2018mar31

Recommendations to newbies on buying, handling, and using micro SD card

/ to continue, ...

tlfong01
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