LCD / motor / hotend / thermistor issues


Hi all, I’ve just finished building a self-sourced Wilson 2, but am running into a number of issues.

I can connect to the printer in Pronterface, but the LCD doesn’t function. The backlight powers up, but the display doesn’t initialise (two horizontal bars across display). Also, both thermistors are intermittently reported as MAXTEMP, indicating a short, however I’ve disconnected them from RAMPS and they measure a nominal 100k at their DuPont connectors.

All of the steppers have issues, too. They either make a single clicking noise and then fail to respond when stepped in the positive direction from Pronterface, or else they stutter, or move in one direction but not the other.

The SD card also intermittently fails to initalise. I can tell the hotend to heat up, but the temperature never actually rises.

What is even more puzzling is that I’ve replaced all the electronics in an attempt to solve the problems (new Arduino Mega 2560, new RAMPS 1.4, new A4988 stepper drivers, new RepRapDiscount Smart Controller and interface board), and the same issues persist.

I’ve tried disconnecting input power to the 5V PSU that is powering the servo, guessing that maybe RF interference from the LM2596 buck converter is to blame, but this had no effect.

This leaves either the 12V PSU as the culprit, or some issue compiling/uploading the Marlin firmware. The 12V PSU measures mine at both terminal block power inputs to the RAMPS, and doesn’t sag when I have the heatbed turned on. I’m using Arduino IDE 1.6.8 and the Wilson2 Marlin fork from February this year.

I’d really appreciate any suggestions - this has been quite a puzzling one for me!



I think Marty’s latest GIT build is including the PINs file for his PICO board and the pin mappings are off. I used a PINs file from another Marlin build and that took care of my MAXTemp error.



Thanks for the pointers, Denny. I think I’ve found the issue - my RAMPS board wasn’t seated properly into the connectors on the Arduino. After applying a bit more force and powering back up, everything seems to be working!


That’s great news. I was coming back to say, I no longer think it’s the PINs file.

I’m not entirely sure what fixed it (I changed a few things), but I ultimately commented out line 87 of the Configuration.h, which defined motherboard as Pico and my problem went away.