Project: 3D Printer from scratch. Part 3 – Electronics, issues and blowing fuses

The last parts were delivered from ebay on the 3rd of march. This took a bit longer than usual as I managed to order during the chinese new year.

With all the parts at hand i decided to start building, while the paint on the frame dries I started working on the electronics.

I converted a old Corsair cx430 to work with the printer. At 12v and 430W the supply can output about 35 amps which is more than enough.
Here is a picture of the Mega 2560+RAMPS 1.4 with 5 stepper drivers mounted, 5 motors connected and the hotend connected.
IMG_0701

The firmware I’m using is Marlin. Marlin is a deviation on Sprinter and has LCD support amongst other improvements.

Image of the motors, both Z axises are running.
From left to right:
X axis, Y axis, 2x Z axis, Extruder motor.
IMG_0702

When connecting the LCD I noticed something was off, the display shows garbage and nothing can be read from it.
IMG_0709
The almighty google suggest multiple possible errors.
First thing to troubleshoot is to see if there is any noticable soldering junk creating crosstalk, I checked both the LCD PCB and Mega2560+RAMPS PCB but I could not find any. I then proceeded to checking the Marlin code to see if I had made any configuration errors.
Unfortunately I had no luck there either.
As a LCD is not required I decided to move on. When the printer is up and running I will probably deal with the LCD errors.

Then I went ahead and configured the endstops. This proved an issue. I’m using 4 pin Mech Endstop v1.2. I had a hard time figuring out which pin did what and after more google I found out more people had made the mistake to wire them wrong and burn the arduino board.
My approach was to connect a LED to the endstop and a tiny bit of voltage from the PSU.
Unfortunately my calculations were off and I managed to burn the fuse on the PSU! 🙁
Here is an image of the PSU, next to the big brown cable is the burned fuse.
IMG_0707
Soldering off the power cords and fuse and from the PSU was easy, however with the PSU built to be compact it was not easy to solder a new 3A fuse.
Here we can see the PSU out of the case with the old fuse on the side.
IMG_0713

With the endstop issues solved and PSU works great the main job left is to assemble the printer.
More updates to come!

Ps. More images
IMG_0710 IMG_0703 IMG_0700 pronterface

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