Probably belongs in Craft Punk since it’s their chair, but it seems a bit weird there.
I pulled out the batteries yesterday and gave them a full charge, which took most of the day. When I put them back in I found it was giving the four-flash error code when trying to drive it, so I started to debug that.
And then there was a small fire.
Aaron mentioned to me that the bus connector that was in the joystick module was crackling a bit - turns out that’s because the bus wire has high-current leads directly to the batteries, and they were starting to touch. Then I moved the wire the wrong way and they welded together and started to generate quite a bit of smoke. I managed to pull the cable out of the connector and stop it before it got out of hand. It was a real pain getting the connector apart and repaired though; so don’t break it again!
In the process of fixing the wiring, I found the manufacturer for all the chair electrics, and a chunk of documentation: http://dynamiccontrols.com/en/downloads/dx
Included in this was an explanation of the error codes. Four flashes means the right motor is busted (and it’s covered in duct tape and zipties, so it’s had an accident before) - and sure enough, when I check it with a multimeter it’s open circuit. Shaking the chair makes it occasionally make contact again, though, so it’s probably repairable, though it’s a bit much for me to take the motor out by myself.
I also found an explanation of the charging system, which is the XLR socket that’s on the front of the joystick module. I’ve grabbed a matching connector out of the boneyard so we can make up a charging cable.
Joystick module: http://dynamiccontrols.com/en/downloads/dx/obsolete-dx-product/66-dx-remg80-a-variants-installation-manual/file
Actuator module: http://dynamiccontrols.com/en/downloads/dx/obsolete-dx-product/70-dx-tam-two-actuator-module-installation-manual/file
Power module: http://dynamiccontrols.com/en/downloads/dx/dx-power-modules/50-pmbpmb1pmb2pmb-s-installation-manual/file
Wheelchair parts/assembly manual: http://www.invacare.com.au/ass/content/584/605/m1-spare-parts-manual2.pdf