Tuesday, April 29, 2014

Delta Bot: First Motion!

I've been fighting with the Arduino Mega and RAMPS 1.4 electronics for the last month or so on the RepRap Rostock clone I'm building. Every time I plug everything in - RAMPS into the 12v power supply, Arduino into the PC via USB cable - the 5V voltage regulator on the Arduino overheats. And not just a little- enough to get hot enough to smoke and eventually pop. I burned out the regulator on one Arduino by leaving it plugged in too long. I ordered a strip of replacement surface mount 5V regulators from ebay- hopefully replacement on the burned out Arduino isn't too hard.

Burned out Arduino Mega 2560 5v regulator- upper left next to the power plug. Note the big hole blown in it!

I tried searching the forums and general google searching to try and find the root cause. No luck- and forum responses were generally about making sure the power supply polarity was correct, etc. After finishing the searches and looking through reprap.org's RAMPS 1.4 page, I thought a possible cause might be some mismatch between the 12v power supply and the power supplied by the USB cable from the PC. The D1 diode on the RAMPS board allows the 12v power supply to also supply power to the Arduino. If the D1 is cut, the Arduino must be powered off the USB- but it wouldn't receive any potentially troublesome power from the RAMPS board. So, I decided to cut the D1 diode. Worst case I can solder in a new diode.

It was pretty tough to actually cut the D1- it's tucked way down next to the stepper driver sockets. (under the "x" and "y" stepper drivers) I ended up cutting it using the tip of an x-acto knife.


D1 is the small black / silver cylinder in the center left of the frame
I plugged everything back in- and no smoke! I left it plugged in with the 12V power supply and USB connected for five minutes, and monitored the 5F voltage regulator temperature with my finger. It seemed to stay cool- so I fired up Repetier Host and tried to make it go:




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5 comments:

  1. fixitMay 10, 2014 at 4:07 PM

    Having the same problem here. Just powered on and it smoked. All wiring is correct. Was just using pwr from the Ramps 1.4 - I guess it just cannot handle it. Thanks for the tip I will try it, usb power is just fine with me.

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  2. M. BogomolniAugust 4, 2014 at 5:53 PM

    Hey there .. I'm switching out many of the parts of my WolfStock for the SnowStock. Do you have your updated files published up on Thingiverse?

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    1. Andrew ForsbergAugust 5, 2014 at 1:16 PM

      The files on thingiverse are the latest version: http://www.thingiverse.com/thing:214848

      I have yet to add an extruder design to the collection. I've been busy with summer and tweaking my MendelMax 1.5 for improved quality.

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  3. AnonymousAugust 11, 2014 at 12:58 PM

    In any project, seeing smoke or a burnt smell is not a good sign. But it’s a learning process. And the best thing to do is to research it online to know what caused it. I just hope the replacement for the burned regulator came on time, so you can adjust it properly. Also, I hope the power supply and other materials are on all compatible. How’s it going, btw?

    Kelley Burton @ Aim Dynamics

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    1. Andrew ForsbergAugust 11, 2014 at 3:43 PM

      Thanks for the comments! I haven't had much time this summer to make much progress on the design & building needed to finish up this printer. Any home hobby time I've had as of late I've been using to make improvements to my MendelMax 1.5 to yield better quality parts for the Snowstock delta build and other uses. I have the new regulators on my work bench- I just need to solder them in and cross my fingers!

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