Wired up everything. Made a ground-rail with six plugs, just enough. Several things still use temporary cables. Had to chop off one of the Z stage opto pins to have room for the extruder stepper. Made the little board for the temperature measuring. Tested all four motors running at the same time, using the stepper library (which doesn't actually have opto endstop inputs). Tried lowering the Z stage to be in proper extrusion height, but found the back of the extruder mount hit the Z stage frame as well as the Z stage threaded rod support. Cut back the support (it's cardboard) and marked where to remove some aluminium from the frame.
Next time: Bring Dremel and dremel out two notches for the extruder mount.
Noticed that the Z stage goes much slower up than down. I should give it some oil and make sure the skate bearing at the bottom is as centered as possible. If that doesn't help, I may have a serious weight problem.
The wiring is still somewhat of a mess, and I had to remove the extruder stepper motor driver from where I had mounted it on the side of the extruder mount, as it was going to hit the bearings for the Z stage plate. Now it's just hanging loose on the back.
The opto endstops are in a somewhat sorry state. The Z bottom stop is not there, and the top one doesn't seem to work, plus it has nothing that moves into it. I should probably find a way to mount the lower one, since knowing when we're at the plate is more important.
When running the Z stage up and down, I noticed the power would go out after about 30 seconds. When I was doing the all-motors test, that didn't happen. So most likely one of the idle stepper motor drivers gets overheated. I may have to look into enable/disable toggling, at least for the Z stage when extruding (since then the X, Y and extruder stepper motors will be running much more than the Z). I could possibly remove the X and/or Y opto endstop, they don't have that much to do when I just start a print somewhere on the middle.
I might want to hook up something I can use to move X and Y manually.