I'm using a Raspberry Pi 3 model B with Raspbian (latest, with PIXEL) with a 16 GB MicroSD Class 10
I've been using the Raspberry Pi since last May (so about 5 months or so) and it's working just fine until September, when it apparently "shuts down" on it's own. The PWR light turns on but the ACT light doesnt. The mouse and the keyboard does not appear to be on. I managed to fix this issue by formatting the SDCard, and write the image to the SDCard. But after a few days the issue appeared to have returned. My friend suggested to boot from the USB and fsck
the SDCard, in case the SDCard was broken, or something. But it won't boot from the USB (perhaps it was because I did something wrong)
Recently I noticed that the ACT light flashed in a specific pattern every few second. I checked the internet and apparently it could mean that the board can not read the SDCard.
I've always plugged out the power supply after the ACT light stops flashing (irregularly) to make sure that the SDCard isn't corrupted. And the usual temperature for the board is around 40°C.
What is happening? How do I fix it and what caused it?