126: PMO

PMO is modern vernacular, short for "Pissing Me Off", or sometimes in past tense, "Piss(ed) Me Off". I had something PMO today, because my electric skateboard is broken until further notice. I learned this this morning, when I went to ride it to Wind Power, and it only spun one of the motors. I didn't have time to deal with it then, so I ran back upstairs, switched it out for the longboard, and then skated to the club meeting.

I hadn't ridden my manual board in a while, and it was honestly kinda nice. The wheels are significantly smaller, so it doesn't drive over stuff quite as well, but I'm familiar enough with campus now that I know where to go and where to avoid, as well as the places that are just going to suck regardless.

I got home at like 2, after we blitzed through the 12-3 lab, and then my 3-6 lab was cancelled today (Huge!), but I've spent essentially the last 8 hours working on the board. I had to take it all the way apart first, which took a while, and then I opened the box that held the ESC and controller, and it had water in it. There's corrosion on the board, and from the behavior of one of the motors, a couple of the pins are shorted internally. I couldn't tell if the chips were dead, or just corroded together, but the outcome is the same.

I tried cleaning the board with IPA, which worked a little, but these chips are small enough that I couldn't resolder them by hand, so there was only so much I could do (it did not work). The board is also bonded to a big chunk of aluminum, so I don't know if I could actually get it hot enough to desolder the components; it might just sink all of the heat into that block and call it a day.

I'm not giving up on this board yet, I just didn't want to make the trek to the hangar for troubleshooting right now. I might make it tomorrow, honestly, because the timeline for a functional replacement is pretty long.

The system is made up of two boards, effectively a control board and a power board. The control board doesn't seem to have received any damage at all, but the power board got corroded on one side (the side that didn't work this morning). I looked at replacing all of the chips on the damaged board, but it would be like $70 in chips, and that's not a guaranteed fix, so I'm not going to buy anything until I've had the chance to desolder and resolder all of the components, because I suspect (by which I mean hope) that only some of them are bad. Desoldering the MOSFETS (power delivery chips) will also allow me to test them, since I'm actually in a class about those right now, so I know how they work.

I also spent an inordinate amount of time trying to get the tool for the other ESC (electronic speed controller) I have working. I have another board that is almost the same thing, but intended for robotics, and if I configure everything right, and get a remote, I could just drop it in as a replacement. That "configure everything right" is doing a lot of heavy lifting though, because the company that made this robotics controller (Odrive) has terrible documentation, and their systems are all very clunky, so it genuinely took me like an hour and a half of troubleshooting just to get the damn thing installed. Even then, I couldn't do anything with it, because the board can't run on just computer power, it needs to be powered externally, and I don't have a power supply in my room. I will also likely try and get that working in the Wind Power room in the near future, since it has all of the tools and power supplies I would need to get that tested. I actually trust that I could get the Odrive working, the problem comes from getting a remote, because the Odrive is a unique controller, it wouldn't play nice with anything else, so I don't know if I could get any fancy features (like board battery levels) working with the controllers. Controllers are also kind of expensive, the one I was looking at that would be really nice if I can get all of the systems working is almost $100, and even the cheapest option is like $40. I didn't end up ordering anything there either, since I'll hopefully get to fix the controller I have, and put off the Odrive conversion project for a while (because I do want to convert the board to that eventually, it gives me so much customization potential).