Heating/Graphic controller issue

Hi,

I have a setup with RAMPS 1.3/Arduino and I recently added a full graphic smart controller (reprapdiscount) to my system. When preheating, the extruder and the bed -almost- reach the targeted temps, but then the text gets very dim, and the entire display begins flickering, which seems to have some connection with PWM somewhere else in the system. If I let it continue to heat, sometimes I also get a "heating failed" error. I have looked many places online and I can't seem to find anyone who has had a similar issue. My configuration.h file is below if anyone would like to take a look, although I believe this is an electrical issue. Also, I noticed the flickering is reduced a bit when I remove the SD card (though the effect is still very prominent). Any help would be greatly appreciated.

Thanks!

--Nick


Configuration.h

I suspect that the voltage on the 5V rail is dropping due to the 5V regulator on the Arduino overheating. You can test this theory by monitoring the voltage on the 5V rail with a multimeter. Arduino/RAMPS can't safely drive a graphics display unless you provide external 5V power.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

dc42,

I appreciate your prompt response. How would I go about fixing this issue? Would I be correct in assuming I could power the arduino from my 12V power supply via the DC barrel jack? If this is the case, would any other modifications need to be made on the RAMPS board? I know the diodes 1 & 2 are involved in transferring power to the arduino, and I'm unsure about how the arduino would regulate it if the barrel jack and input from the RAMPS were both powered.

Thanks, dc

--Nick

Powering the Arduino with 12V through the barrel jack won't help. Powering it from 9V instead of 12V would. Or you can add an external 5V regulator using a 7805 or similar. But first, use a multimeter or check the temperature of the 5V regulator to confirm that this is the problem.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

dc,

Thank you for clarifying, I didn't quite understand the first time. I tested the voltage regulator on the arduino, and it was indeed the reason for failure. I ended up desoldering the D1 diode on the RAMPS board to prevent it from trying to power the arduino, and now the controller is being powered separately from a 9VDC wall wart. I had my first successful SD card print after using this configuration and everything seems to be performing well. The only downside to this new setup is that I must use 2 different power cords, one each for the controller and the RAMPS. I ordered a regulator per your recommendation so I could again try powering the controller from the PSU. I will update this thread once I am able to try out using the regulator.

Thanks again for your help,

--Nick

H Nick,

One nice way of doing it is to use a DC-DC converter and feed that in to the ramps where you removed D1. Here's a converter with built in display, or you can get cheaper ones without the display. You want to set the voltage high enough to ensure no drop-out from the 5V regulator, but as low as possible to reduce the heat that the regulator has to dissipate. I suspect between 7.5 and 8V is ideal.

JamesK,

Thank you for your suggestion. Coincidentally, that is the exact thing I ordered, and I look forward to trying it. I should have it by the end of the week. I will update to post my results.

I appreciate your response.

--Nick