Not power on

[DarkSSide]

Ok so I did all the soldering and all the hook ups but when I plug into the outlet the little red led just flashes once and nothing comes on. Any help is appreciated.
Thanx

[Felix]

Blink once means momentary button mode.
Did you press the button?

[DarkSSide]

Ok I resoldered the connections at the USB connection. That seemed to do it but now I get the rainbow color box at the top right corner.

[DarkSSide]

Also it just reboots even if I hold down the button for 2 seconds or more. It won't totally shutdown.

[Felix]

Watch the video to see the diff between reboot and shutdown, and the delays. Keep the button at least 3 seconds until the Button-LED starts to pulse.
What PSU do you have?
There are some notes in the guide that explain what you need to do to minimize the effect of poor wiring and causing the rainbow (voltage warning). Use thick and short wires for power. If its not a good PSU, combined with voltage drops introduced by long thin wiring or poor solder joints, it will result in the rainbow.

[DarkSSide]

Right now my PSU is the Cana plug that's 2.5.

[Felix]

That's a good one.
Can we see closeups of the board and your wiring to the Pi?

[DarkSSide]

Got it to power down.
Here is a close up of the board.

[Felix]

I cant really tell too much detail from that, but assuming soldering is good... I would like to see the status LEDs with the Pi fully booted.
So SHUTDOWN works now?