Please Help

[StophosG]

I recently purchased an iduino mega r3, a ramps 1.4 to, 4 stepper motors, and an LCD 2004 to build a 3D printer for my school science fair project. When I send power to the iduino alone it lights up and works fine, but when I attach the ramps 1.4 and the rest of the electronics and give power nothing works. This project is due Wednesday and I don't know what to do. Please help.

[zhangxueyou]

Could you please take some pictures of the board?
Please swap the connection of 2 cables behind LCD, see if works.

[StophosG]

I can post pictures tomorrow morning. I have a feeling that the problem goes further than the LCD cables being switched. To try and see if the problem was one of the smaller items I removed everything I had connected to the ramps 1.4 including the LCD and the stepper motor drivers and just applied power to the connected ramps and iduino and still none of the LEDs lit up or anything.

[zhangxueyou]

Is the power from power supply? Did you plug USB cable when giving power?

[StophosG]

I cut the end off something like this, stripped the coating of the ends of the positive and negative wires and screwed them into the ramps 1.4.

[zhangxueyou]

Yes, the power come from that 4 wires. Is the input AC volatage to power supply as same as the AC voltage in your district? If yes, we need to check the connection of endstops, stepper drivers, jumper caps under stepper drivers.
So I need some pictures of mainboard.

[midiman310]

I recently purchased an iduino mega r3, a ramps 1.4 to, 4 stepper motors, and an LCD 2004 to build a 3D printer for my school science fair project. When I send power to the iduino alone it lights up and works fine, but when I attach the ramps 1.4 and the rest of the electronics and give power nothing works. This project is due Wednesday and I don't know what to do. Please help.

I cut the end off something like this, stripped the coating of the ends of the positive and negative wires and screwed them into the ramps 1.4.

What is the rating of that power supply? When plugging into the RAMPS board 12V connections, with 4 steppers wired in, that power brick needs to feed approximately 4Amps without a Heat Bed and Hot End Attached. The motors enabled will drag the voltage of the power brick down below the operating voltage if it cannot provide the current. The image is too small, so I cannot see what current the power brick you have in the picture is rated at. That brick appears to be too light in power. When you plug that power brick in, what voltage are you seeing at the screw tops of the green connectors '+' and '-' terminals. If it's somewhat near 12V, then make sure the RAMPS is 'married' properly to the MEGA board. If the power brick is rated properly, and connection between the RAMPS and MEGA are solid, double check the installation of you Pololu Stepper drivers to make sure there's no dead short.

[StophosG]

Here are some pictures. Let me know if you need anymore.

[StophosG]

Here are some pictures, let me know if you need more.

[zhangxueyou]

Juper caps are well plugged, and steeper drivers have been plugged correctly.
But I find that you only use one group of power for mainboard, and the current is far less than the needed current. The mainboard needs a couple of Amps current. You can see midiman310's suggestion.
The mainboard needs 2 groups of input voltage with 12V, as you can see there are 4 connectors for connecting power supply.
We use such a power supply,with 2 groups of 12V output voltage, to give power to mainboard:

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