Stepper problem resolved.. Now summer vs Mendel

The problem I described in my previous post has been resolved! It turns out that I didn’t fry *any* of the stepper driver boards, and now I have two to spare. 🙂

The boards I thought were bad were suffering from not getting 12V or GND connections on both sides of the board. Contacts would be made somewhere, but not everywhere. Enough was connected that the green power LED would light up, but no power would make it to the stepper motors.

I desoldered the screw terminals on both fully-modified boards and fixed them. To make sure I was getting contact on both sides of the board I figured I’d play it safe – I took one of the metal contacts I’d ripped out of an RJ45 jack and soldered it in along with the screw connector. First, I soldered it on the top:

Then I bent it beneath and cut it to length:


I soldered the screw connector on after that and everything worked fine!

I mounted the boards on the Mendel again, and stopped for dinner.

One point worth mentioning for anyone following down this path.. The way I was determining if a board was working was by connecting it via ribbon cable to the motherboard, connecting power, and then looking for lit LEDs next to the ABCD stepper motor connectors (such as the incredibly bright red LED in the first video above). However, I later discovered that this method only works when connected to the X or Y stepper driver port on the motherboard. The Z stepper driver board won’t light up those LEDs, even though the board is fine. (I went through a quick discouraging moment where I thought I had a bad cable or Z port on the motherboard). Actually using the RepRap host to move the motor, however, works.

Once I realized this, I remembered reading that the Z motor is only enabled when it’s needed (since it’s used far less during a print). I think that even might be configurable in the firmware, if memory serves. That’s also probably the enable line that everyone was talking about before (either in the comments in the last post, or in various threads on the Mendel forum).

Now my biggest obstacle is the summer. 🙂 Trying to get our pool usable is eating up daylight, and once it’s open, that will eat up more daylight. Maybe I’ll be building by night. 🙂

p.s. Just because this post is so short, here’s a quick video showing the acceleration that RepRapHost (or actually probably the FiveG firmware) does during simple move commands:

7 Responses to “Stepper problem resolved.. Now summer vs Mendel”

  1. nuttzy says:

    you’ll have to water proof your reprap so you can work by the pool 😉

  2. Come on! post something! I want to see that mendel working 😉

    nice job on this walkthru…

    • jkeegan says:

      😀 I so want to, trust me.. Last Friday I found out that a work deadline I thought was five weeks away was reduced to only two weeks away, so I’ve been working weekends and completely avoiding the RepRap timesink (which hasn’t been easy!).

      Before that I did get some wiring work done, and I have Z-axis somewhat working as long as I move slow enough.. If you want to spoil the next post, here are some previously updated (but not yet blogged about) youtube videos:

      After next Friday, I certainly hope to have more time! I’m pretty damned close! I wrote out a completely exhaustive list of EVERYTHING I have left to do (including building the extruder, all of the wiring, etc) and it looks like I have about 37-52 hours of work left (with lots of padding in there, so hopefully it’s a lot less than that).

      Thanks for caring! 😀

  3. nuttzy says:

    So, is that deadline this Friday or next 😉 btw, your blog has a nice mobile UI… good for my aging G1

    • jkeegan says:

      It was next (which is now this) Friday, but it just got moved to Tuesday (one week from today), which is good for me and bad for you the blog-reading public. 🙂 Actually if I don’t get everything done by Friday it might be bad for me too, since we already pushed off Father’s Day from last Sunday to next Sunday. 🙁

  4. I wish I was on the electronics part of my mendel… hope you find out what it the problem with the Z axis, looks like something it not squared…

    you can look at my blog and see the pics of my Mendel assembly…

    the text is in portuguese, but you can look at the pictures and tell me if its looking ok…


    Antonio Santos

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