Powering my ramps 1.4/arduino/lcd

I am working on a reprap with my son as a father/son project.

So far we have the reprap built, and the arduino/ramps1.4/graphic lcd programmed. When powering the arduino via USB everything looks good, menus work, everthing displays properly. however now that I am wiring it all up I'm having problems.

I'm using a 12v 10A power supply(I know I need a bigger one) but nothing powers up. I tested with my DMM and I'm getting 12.3V from the supply with no load. I know the steppers and arduino run on 5V, but I have no 5V power so I think that is the problem.

Is there a way to let the 12V step down to 5V to power everything? I'm expecting a jumper somewhere, but I've been unable to figure it out.

Is diode D1 installed on your RAMPS? You need it to pass the 12V supply on to the regulator on the Arduino.

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I'm pretty sure it was, but I'll check again when I get home.

Make sure it's oriented correctly too. It should be installed so that the stripe is on the left side, towards the fuses.

Also your steppers run at whatever voltage you have supplying the ramp board. The drivers are controlled via 5V signal coming from the Mega board.

The diode is in. Does this look correct?



Jumpers? Power?

You are currently only powering the heated bed as wired. With only a 10A power supply, you need to move your supply wires to the other two terminals which supply power for everything but the heated bed. If you had a larger power supply, you could supply power to both pairs of connectors.

Also, remove the green jumper that's connecting PS_ON to 5V. If anything, it can connect Vcc to 5V. But if you aren't using any of the servo connections, you can just leave it off or hanging on 1 pin. It definitely shouldn't be how it is and may lead to future issues.

do you know much about electronics? you could either purchase a voltage regulator that brings voltage down to 5v, or make one using a 7805. not much should be powered from the arduino 5v regulator, at least with out a fan facing the circuit board and a heat sink on the voltage regulator on the arduino board. although for genuine arduino boards i guess people have been doing it without issues for some time. but as displays are getting bigger and additional add on electronics that use more current appear i would imaging that at some point it will all not work so good.


another trick is to have the arduino powered by a usb wall adaptor, 500-1000ma provided by most of those is enough, more current the better, and leave d1 diode out of circuit. the issues is that 12v to 5v drop is alot of power to absorb, even more so if you up the voltage to more than 12v. having the 5v regulated off the arduino board solves some issues with increased power usage.


here is a web sight that shows where the voltage regulator is located. this is where the voltage is reduced to 5v.[www.jameco.com]

Edited 3 time(s). Last edit at 03/03/2015 11:25AM by jamesdanielv.

I do know a little about electronics, the RAMPS board is new to me though. My concerns here was that if I hookup 12.3V to the 5V terminal I would fry something. Also I thought the steppers were run off the 5V terminals, a 7805 wont be able to handle that, they are only good to ~1A

Can I put 12.3V on both terminals? Will the ramps board drop it to 5V for the arduino?

sounds like I need to do the following, please correct me if I'm wrong

1) leave the 12.3V connected to the heatbed.
2) rig up a power regulator that puts out 5V from 12V, for the other two terminals????

#2 is not an issue really, but it would have been nicer if the RAMPS board simply took 12V across the whole thing. That would mean I only need one power supply.

Quote
BitRacer
Can I put 12.3V on both terminals? Will the ramps board drop it to 5V for the arduino?

sounds like I need to do the following, please correct me if I'm wrong

1) leave the 12.3V connected to the heatbed.
2) rig up a power regulator that puts out 5V from 12V, for the other two terminals????

You want 12V on both supply inputs. 12V will be supplied to the Mega board and it's voltage regulator will regulate it down to 5V. This is the typical way of doing it and won't damage your Mega board. This will also run your steppers at 12V which is what you want.

10A is NOT enough to run electronics, your steppers, hot end, AND a heated bed. 10A is barely enough to run a heated bed alone. Until you get a larger power supply, just forget about running a heated bed as it's not going to happen.

thats great, I'm still getting everything wired up right now anyway. I'm hoping I can see the steppers move this weekend, and I should have a 30A power supply in the next day or so.

Maybe I'm being overly cautious, better safe than sorry right?

Got the power supply today and I should have a spool of filament tomorrow.

The 30A supply is working well, the ramps board and lcd power right up when I put 12V on both rails.

Hopefully I can get an auto home test tomorrow or friday

thanks for the assist guys