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I started new with Raspberry Pi 2 a few weeks ago and I noticed something strange. Sometimes when I want to switch it ON, it does not switch ON, and instead both the red and yellow LEDs go ON, no blinking tho. But if I take out the power and eject the SD card and then insert the SD again and I try then it will turn ON.

What causes this? And how can I prevent this in case my raspberry pi is supposed to restart automatically repeatedly?

  • Which model Pi? – joan Jul 13 '15 at 8:44
  • Sorry forgot to mention that. I will edit the question now. – Ahmed Al-haddad Jul 13 '15 at 8:45
  • It might be worth looking through elinux.org/R-Pi_Troubleshooting if you haven't already. – joan Jul 13 '15 at 8:47
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    Maybe the SD card (holder) is slightly loose? – goldilocks Jul 13 '15 at 11:52
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I had the same problem in my Raspberry Pi B+, the reason of no blinking LEDs is that there is power but the SD card isn't being read at that time. So Pi is nothing but a brainless powered card. You should make sure SD card hub is clean and dustless, it might cause corrupt connection which will end with the situation you have.

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I've run into strange issues where the RPi is not getting enough power. I wouldn't power the RPi from a USB port on your laptop and make sure the wall plug supplies at least 2 amps.

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If you've got a display connected to your RPi, check to see if you have a little 4 color square in the top-right of the display when it does boot. If so, that's a sure indication you have inadequate power.

A lot of cheap power adapters have sufficient specs, but cheap cables or other factors result in inadequate power making it to the RPi. I recommend some of the heavier-duty adapters from Adafruit and other RPi sellers.

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Thanks to everyone who helped. This should give an extensive answer as taken from http://elinux.org/R-Pi_Troubleshooting#Pi_boots_sometimes_but_not_always

With a known good power supply and known good SD card, the R-Pi boots occasionally, but other times shows only a tiny green flicker from the "OK" LED and it fails to start, even with no USB devices and no Ethernet. This has been reported several times[6] [7] [8] and remains an open issue. Low voltage or an improper SD card can cause it. Some SD cards will work until they warm up slightly, and then fail[9]. When exposed to 21 C room temperature the warmest part of an uncased working R-Pi should be 41 C[10]. The wiki has a list of working SD cards. Buy from a reliable vendor as it has been claimed that 1/3 of all "Sandisk" labelled memory cards are counterfeit.

  • It could be that the SD memory card is not making proper contact with the Raspberry Pi. Look at the SD card holder on the Raspberry Pi carefully. At first glance it may look fine, but the contacts must be springy and they must protrude at least 2mm as measured from the lower edge of the holder to the top of the contact bulge. Variations happen due to the solder process and the type of holder used. Some of the solder residue falls into the contact cavity, restricting the springiness and the height that the contact protrudes. You can fix this yourself, but remember you can void your warranty. The contacts are delicate, so be careful. Insert a needle pin under the contact bulge and pull lightly up until the one end of the contact unclips. Clean the cavity where the contact unclipped from any solder or other residue by blowing into the cavity. Clip the contact back into the cavity by lightly pushing it into the cavity. Do this for all the contacts. Refer to these photos: Media:SDcardHolder.JPG, Media:UnclipContact.JPG, Media:UnclippedContact.JPG

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