I'm in the process of upgrading my RepRap Pro  Huxley to Marlin thanks to

I’m in the process of upgrading my @RepRap_Pro Huxley to Marlin thanks to a new 1284p chip. So far it compiled and transferred to the chip, but I’m having problems with the extruder. On a G1 E5 F500 it simply starts the extruder and doesn’t stop, the wheel is just turning and turning until I reset the controller. My current config (and firmware) can be seen here: https://github.com/splitbrain/Marlin/tree/master/Marlin

Does anyone have an idea how to fix this?

also posted here http://www.emakershop.com/forum?vasthtmlaction=viewtopic&t=941#postid-4968 with a bit more info

I blew up my last micro controller. This might be a good option for the repair.

Can you do a diff on the fork you have made from our repo and so we can see what you have changed? BW Adrian

@RepRap_Pro sure, here the diff: https://gist.github.com/splitbrain/4988597 - no changes except config parameters. The only other thing I had to change was one line in the Sanguino sources to compile on my Ubuntu system as described at http://arduino.cc/forum/index.php?topic=76299.0 Maybe the problem lies there? I used Arduino 0023 + the suggested zip file from http://reprap.org/wiki/RepRapPro_Huxley_maintenance

the arduino forum seems to be down. My change was to comment out the following line in hardware/Sanguino/cores/arduino/wiring.h:
#define round(x) ((x)>=0?(long)((x)+0.5):(long)((x)-0.5))

@RepRap_Pro @Adrian_Bowyer I’m still struggling with this. Can you give me any idea what might be wrong? Is there some way how I can debug this? I’m confident in reading source code but am an absolute noob in electronics so any pointers would be greatly appreciated.

Hi Andreas, I have downloaded your software and I am running through some experiments.

Best wishes

Hi Andreas, I have downloaded your fork of our Repo and uploaded it into one of our Sanguinololus. The extrude functions works fine for me so we know it is not your branch of the firmware that is causing the problem. That just leaves electronic problems. I suspect an intermittent connection with the new chip. Can you look down the rows of pins from the end of the circuit board by the temp connections and see if any pins are bent. This can happen easily when such a big chip is plugged into its socket.

Best wishes

@RepRap_Pro @Adrian_Bowyer thanks for the reply and tests. Yes, seems plausible that it is an electrical problem since I didn’t change the software. So here is what I did:

  • disassembled the board from the printer and checked all soldering joints for bent connections or obvious shorts -> found nothing
  • looked if the chip is inserted correctly -> looked fine
  • carefully removed the chip again and checked for bent pins -> all as straight as new
  • inserted the chip again, messed up and bent a pin -> now I know what you where looking for :wink:
  • straightened the pin and reinserted the chip carefully and correctly
  • reassembled everything

The problem unfortunately still persists. Everything is fine except for the extruder spinning endlessly until reset. (BTW: it might be useful to know that it will only start spinning when the correct gcode was sent, not on it’s own when powering the board).

To make absolutely sure there is nothing wrong with any of the other electronics, I removed the 1284p again and reinserted the old chip. I checked all axes and the extruder and everything works exactly as it should so the electronics are fine.

So any other ideas what could cause the problem? From what I understand the firmware is checksumed when transferred to the chip, so we can be sure their wasn’t a problem on the transfer, right?

Could the chip itself be defect?

It certainly looks to me like the chip is at fault. One final test before we conclude that though - can you swap to the Pololu driver for the extruder with the driver for one of the axis and see if the problem stays with the extruder or moves to the axis where you put the driver. If it moves the driver is at fault, if it doesn’t, the chip is at fault and we will of course replace it.

Best wishes

@RepRap_Pro @Adrian_Bowyer well, since the extruder works just fine with the old chip, I guess we can exclude a faulty driver. Thanks for your help, I’ll mail the chip back to you.