Both LEDs flashing, no startup

[JohnnyCheesedog]

First time user of any incarnation of the Raspberry Pi, and I had hoped to get a 3 model B on which to install Retropie 3.7 using this guide: http://lifehacker.com/how-to-turn-your-raspberry-pi-into-a-retro-game-console-498561192

After trying with two separate Pi 3s and several different micro sd cards all with fresh writes of the Retropie files, however, I keep encountering the same error message. The red led flashes twice, and then the green flashes once with the red. I cannot seem to find this error reported anywhere else and am frankly a bit flustered. My television seems to intermittently detect the Pi, flashing the hdmi indicator, but little else seems to happen. Any helpful suggestions?

[herb_fargus]

@JohnnyCheesedog did you follow this guide? https://github.com/retropie/retropie-setup/wiki/First-Installation

possible you picked the wrong SD image, have a faulty cable or sd card or power supply

[JohnnyCheesedog]

@herb_fargus I did encounter that guide, yes. Though I've noticed my power supply is only 2A - I assumed it would be the requisite 2.5 seeing as it shipped with the chipset. If I were only attempting setup with a keyboard plugged in, would that difference still be enough to cause problems?

[Finhead]

@JohnnyCheesedog

I would def get the proper power supply. 2.5 amps is what you need for the Pi 3.

[herb_fargus]

@JohnnyCheesedog even if its underpowered it should still boot in theory, I think its still more likely an SD card or hdmi cable issue but I'm not positive. Only way to check is to try other hardware just in case.

[JohnnyCheesedog]

@herb_fargus The micro sd is new as of today after exchanging the previous one, so I'd hope that's not the problem. Seems the hd cable works with my consoles, too. Thanks for the suggestions, though. I might have to chalk it up to the power supply.