Anycubic Kossel Linear Plus to Duet3D – Part 2: Stock “Gotchas”

The documentation for physical assembly and wiring is EXCELLENT.  Large illustrations of steps; hardware in bags. Assembly is straightforward and only took a few hours, maybe three or four, to first power up. There were a few things to note:

The first two “Gotchas” are with regard to the power supply wiring.  Anycubic sends it pre-soldered.  There are two problems with this.

1) Soldered power wires.
Soldered wires in a screw terminal results in the solder deforming over time and the connection loosening.  This leads to heat.  A vicious circle forms and there is at least some fire danger.   Bad, bad, thing in what is otherwise a very nice kit. Also, the soldered ends on the wires from the power supply are much too large to insert in the screw terminals.

2) Blocked access to power connector screw.
The pre-mounted main board is in a position that causes it to completly block one of the screw terminals for incoming power. Not that big a deal… loosen the board, connect the wire, re-mount the board, right? At the same time, this ENSURES that this particular screw will never be tightened after original build; couple that with solder/screw that works loose, and gotcha (1) and (2) synergize to be even more dangerous.

I ended up cutting the soldered ends off the power supply wires, and all the heater wires, and crimping on “Bootlace” terminals.  Some builders, maybe even most, will not have the crimp tool and terminals…

The third “Gotcha” is much more frustrating (and less dangerous).

3) Z-Probe doesn’t work.
The Z-Probe is “backwards” to the firmware with regard to “Normally Open” (NO) vs. “Normally Closed” (NC). The first runs of “Automatic Leveling / Set Z height” resulted in a Home, a bunch of wiggles, and a reboot. Sigh…

It is possible to correct this by inverting Z+ pin in firmware, or by changing the microswitch in the probe. I chose to change the physical probe. Mainly because it was shipped as NO and that is the same as a probe not plugged in at all… I specifically desired NC so that a broken wire or loose connection would behave as though the probe was already triggered. Keeping in mind the long range goal is to install a Duet controller, I wanted the probe to be NC for the Duet as well. The Duet will work with a probe either way; again, I want broken/missing to be detected, BEFORE a nozzle crash.

If you choose to modify the probe, open it up, then cut the trace going to the “furthest” pin on the switch, and solder a wire to the center pin instead. Use a SMALL wire; it has to fit in a channel in the aluminum chassis of the probe.

This is frustrating because the instructions are very clear about how to auto-Z-calibrate and auto-level. This is one of the most important features to make a Delta acceptable to people who’ve never had a Delta before. The failure mode, just wiggle at the top, is NOT illuminating to the actual problem… Sigh…


Click here for Part 3

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