Talk:PCB adaptions for Mendel
Jkeegan 04:24, 30 November 2009 (UTC) - Here's just a little feedback from someone going through all of this for the first time. Not wanting my first RepRap experience to be a SMT-soldering exercise, I'm one of the people in the boat you describe here - someone with pre-built generation 3 boards, but who is building a Mendel. While this issue (makerbot wiring vs mendel wiring) hasn't actually kept me awake at night with worry, it has at least caused me some worry and has slowed down my plans a bit. It certainly has to be having the same effect on others as it has had on me - it's yet another thing to have to worry about (and decide on), at a time when there are so many other unknowns to a RepRap beginner that it just amounts to a big unwanted distraction.
At the very least, it would be good to know which of these modifications are separate from each other, and which are at all required. Someone building their first RepRap probably wants to get something working first rather than having it look pretty and trimmed when it does work, and can push off the beautification aspects until later. That's certainly what I've been tempted to do with the RJ45 connectors on the extruder controller and motherboard, for instance - leave them alone for now, even with a long dangling patch cable in there, and fix them up later.
However, it doesn't seem to me (please correct me if I'm wrong) that it's a clean cut decision of "use RJ45 or use headers". In this same document describing the replacement of RJ45 jacks, there are also replacements of power connections, additional capacitors, and clipped resistors. Question: Is the power cable issue actually a non-starter for Mendel, vs just not looking pretty? Will I actually not be able to create a workable Mendel with all default-configuration boards (RJ45 jack, chunky 30 ohm resistor, and all) because normal power supply cables won't be able to reach the motherboard or stepper driver boards in their proposed location, for instance?
Once you're through a project and have it working, small/medium modifications to it can be an interesting additional project. Before you've ever had the project working though, those same modifications can seem huge and add to one's uncertainty and initial fears. I'm not tooooo worried about myself, really, I'm more worried about what percentage of people we have coming in trying to build this that it turns off or confuses.
I'm mostly sure that once I'm through this and wired it up, I'll look back and say "Wow that was a pathetic thing to worry about". But right now, where I'm at, the thought of ratcheting up power connectors side by side from my three hard-to-acquire SMT stepper driver boards (while desoldering them) sounds like quite a diversion from where I want to go - to a working RepRap that can print. So I want to avoid as much modification as I can, yet I still want this to be laid out as a functioning Mendel, and worry whether ATX power supply cables everywhere actually require this modification.
Anyway, that's what it feels like where I'm sitting right now. Identifying which of these modifications are really needed for Mendel (and which go with which - these components are for the power connector replacement, etc) would help a lot, IMHO.
Jkeegan 02:07, 8 December 2009 (UTC) - Even though Opto Endstops aren't shipped pre-built, this would still be a nice page to show how they're supposed to be wired. It would also be nice to have a quick bill of materials for this page, such as:
Stepper Driver Boards (3) ========================= 3x: 3-pin 2.54mm-pitch pin-strip connector 3x: two-way 5.08mm-pitch screw connector (for 12V wires) 3x: 4-way 3.81mm-pitch screw connector Motherboard (1) =============== 1x: 3.3 volt regulator (78L33 - get the TO-92 packaged one) 1x: 100 μF capacitor 5x: 2.54mm pin headers (2 pins, breakaway headers are fine) tiny bit of insulated wire to connect power to USB Extruder Controller (1) ======================= 1x: 2.54mm screw connector for 12 volt power 1x: 2.54mm 2-pin header (for RS485 comunications) Opto Endstops (6) ================= 6x: 3-pin 2.54mm-pitch pin-strip connector (plus some ribbon cable and compatible connectors for the opto endstops?)
Jkeegan 22:12, 21 May 2010 (UTC) - I want to add a big warning to this page that warns people to be extremely careful, as it's very easy to fry a stepper controller board, but I don't want to introduce unnecessary FUD (fear, uncertainty, and doubt). I've fried three boards already, even when trying to be careful.
