<p>Yes you can, that is the purpose of diode <code>D1</code> on the RAMPS board.</p>
<p>It should be noted that if the RAMPS 1.4 does not have diode <code>D1</code> then the Mega2560 will/can not be powered via the RAMPS board and it is necessary to power the Mega2560 separately, for example via the USB.</p>
<p>See <a href="https://reprap.org/wiki/RAMPS_1.4#Power_for_the_Arduino_Mega_board" rel="nofollow noreferrer">2.7.1.1    Power for the Arduino Mega board</a> on the <a href="https://reprap.org/wiki/RAMPS_1.4" rel="nofollow noreferrer">RAMPS 1.4</a> RepRapWiki page:</p>
<blockquote>
<h3>Power for the Arduino Mega board</h3>
<p>The RAMPS 1.4 has a 1N4004 diode labeled D1 which allows 12V to feed
and power the Arduino Mega 2560 board. This diode is installed in most
pre-assemble boards, thus the Arduino board is powered by the Ramps by
default.</p>
<p>When the RAMPS is not powered or if the diode is not installed or
cut/removed, the Arduino gets its power from USB or a power supply
connected to its 2.1mm (center positive) power jack.</p>
<p>The Arduino provides a Vin connection to connect an external power
source that can be from 7V to 12V, remember the diode D1 can not be
connected if you plan to power the Arduino using its Vin.</p>
<p><a href="https://i.sstatic.net/Tk5Sr.jpg" rel="nofollow noreferrer" title="Where to find the D1 diode (note that D2 is shown at the left, not D1)"><img src="https://i.sstatic.net/Tk5Sr.jpg" alt="Where to find the D1 diode (note that D2 is shown at the left, not
D1)" title="Where to find the D1 diode (note that D2 is shown at the left, not D1)" /></a></p>
<p><em><strong>The Arduino Mega is not rated for voltages higher than 12V. If your board has a 1N4004 diode soldered in Diode D1 (which is the case with
most assembled board), do not apply more than 12V in the 5A connector
of your Ramps, refer to RAMPS 24v for more information.</strong></em></p>
</blockquote>

CC BY-SA 4.0
2022-03-09T06:21:34.600Z
2022-03-09T06:21:34.600Z
Greenonline
<p>Can I plug Arduino Mega USB input (to supply power) and RAMPS 1.4 power input at the same time?</p>
<p>This is because when I plug the PSU into the RAMPS 1.4 alone, the LCD keeps restarting and it just gets stuck at the Marlin logo but if I plug the USB to the Arduino Mega alone, it works perfectly fine except the motor won't move (maybe not enough power) or maybe there is any other suggestions?</p>

CC BY-SA 4.0
2022-03-08T17:41:51.573Z
Considering the amount of questions and problems with the RAMPS shields, I'd advise you to buy a proper control board and a decent power supply. The
RAMPS shields are pretty outdated nowadays.
0scar
CC BY-SA 4.0
2022-03-08T18:16:09.107Z
Can you suggest the proper control board?
Michael
CC BY-SA 4.0
2022-03-08T19:02:36.577Z
Any 32-bit board, look at the BTT SKR boards.
0scar
CC BY-SA 4.0
2022-03-09T06:29:37.043Z
"any other suggestions?" - Disconnect the heated bed (in order to reduce the current draw) and hopefully that will solve the immediate issue. Then use your second PSU to power the heated bed separately, using an external MOSFET, as per [this previous answer](https://3dprinting.stackexchange.com/a/18911/4762). You shouldn't need to provide a separate USB power supply once you have done that.
Greenonline
CC BY-SA 4.0
2022-03-09T07:00:01.273Z
But I didnt install any heated bed.
Michael
CC BY-SA 4.0
2022-03-09T09:12:25.480Z
Ah ok, but in your first question you stated "I total my heatbed + hotend + other components", so I assumed that you had. So, what exactly is connected to the PSU? Just the RAMPS and the motors? Anything else? Hotend? Maybe it is just me, but this is getting rather confusing, and it is unclear what is causing the current draw (if indeed that is the actual problem that's causing the PSU restarts). Also, do both PSUs behave in the same manner, both of them are stopping and starting?
Greenonline
CC BY-SA 4.0
2022-03-09T19:14:24.217Z
I install hotend, 4 nema stepper motor, cooling fan for hotend,lcd, RAMPS 1.4 and Arduino mega 2560 with the PSU. Both of the PSU will not on and off automatically if i only check the PSU with LED. But it will starting to on and off automatically if I plugged in the RAMPS 1.4
Michael
<diy-3d-printer><ramps-1.4><power-supply><ramps><arduino>
Can I plug in Arduino Mega USB input (to supply power) and RAMPS 1.4 power input at the same time?
Michael
# Can I plug in Arduino Mega USB input (to supply power) and RAMPS 1.4 power input at the same time?

(Asked by: username_0 on 2022-03-08)

Can I plug Arduino Mega USB input (to supply power) and RAMPS 1.4 power input at the same time?

This is because when I plug the PSU into the RAMPS 1.4 alone, the LCD keeps restarting and it just gets stuck at the Marlin logo but if I plug the USB to the Arduino Mega alone, it works perfectly fine except the motor won't move (maybe not enough power) or maybe there is any other suggestions?

**Tags:** diy-3d-printer, ramps-1.4, power-supply, ramps, arduino
> **Comments:**
> **username_1**: Considering the amount of questions and problems with the RAMPS shields, I'd advise you to buy a proper control board and a decent power supply. The RAMPS shields are pretty outdated nowadays.  
> **username_0**: Can you suggest the proper control board?  
> **username_1**: Any 32-bit board, look at the BTT SKR boards.  
> **username_2**: "any other suggestions?" - Disconnect the heated bed (in order to reduce the current draw) and hopefully that will solve the immediate issue. Then use your second PSU to power the heated bed separately, using an external MOSFET, as per [this previous answer](https://3dprinting.stackexchange.com/a/18911/4762). You shouldn't need to provide a separate USB power supply once you have done that.  
> **username_0**: But I didnt install any heated bed.  
> **username_2**: Ah ok, but in your first question you stated "I total my heatbed + hotend + other components", so I assumed that you had. So, what exactly is connected to the PSU? Just the RAMPS and the motors? Anything else? Hotend? Maybe it is just me, but this is getting rather confusing, and it is unclear what is causing the current draw (if indeed that is the actual problem that's causing the PSU restarts). Also, do both PSUs behave in the same manner, both of them are stopping and starting?  
> **username_0**: I install hotend, 4 nema stepper motor, cooling fan for hotend,lcd, RAMPS 1.4 and Arduino mega 2560 with the PSU. Both of the PSU will not on and off automatically if i only check the PSU with LED. But it will starting to on and off automatically if I plugged in the RAMPS 1.4  

---

## 1 answers

### Answer by username_2 on 2022-03-09. Score: 1

Yes you can, that is the purpose of diode `D1` on the RAMPS board.

It should be noted that if the RAMPS 1.4 does not have diode `D1` then the Mega2560 will/can not be powered via the RAMPS board and it is necessary to power the Mega2560 separately, for example via the USB.

See [2.7.1.1 Power for the Arduino Mega board](https://reprap.org/wiki/RAMPS_1.4#Power_for_the_Arduino_Mega_board) on the [RAMPS 1.4](https://reprap.org/wiki/RAMPS_1.4) RepRapWiki page:

> ### Power for the Arduino Mega board
>
> The RAMPS 1.4 has a 1N4004 diode labeled D1 which allows 12V to feed
> and power the Arduino Mega 2560 board. This diode is installed in most
> pre-assemble boards, thus the Arduino board is powered by the Ramps by
> default.
>
> When the RAMPS is not powered or if the diode is not installed or
> cut/removed, the Arduino gets its power from USB or a power supply
> connected to its 2.1mm (center positive) power jack.
>
> The Arduino provides a Vin connection to connect an external power
> source that can be from 7V to 12V, remember the diode D1 can not be
> connected if you plan to power the Arduino using its Vin.
>
> [![Where to find the D1 diode (note that D2 is shown at the left, not
> D1)](https://i.sstatic.net/Tk5Sr.jpg "Where to find the D1 diode (note that D2 is shown at the left, not D1)")](https://i.sstatic.net/Tk5Sr.jpg "Where to find the D1 diode (note that D2 is shown at the left, not D1)")
>
> ***The Arduino Mega is not rated for voltages higher than 12V. If your board has a 1N4004 diode soldered in Diode D1 (which is the case with
> most assembled board), do not apply more than 12V in the 5A connector
> of your Ramps, refer to RAMPS 24v for more information.***


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