@dc42 I am using the Toolchanger config.g that you provided (in a different thread to someone else some time ago, before the current repository) for 4 titans but not centred. There were still changes you were making I think as I still get the occasional message that I should replace a "G1 S" code with G1 H in various macros. I will look at your later version and make adjustments.
For Titan tools I currently use extruder acceleration 2500, max speed 5000, and jerk 200. I would like to use higher jerk but that makes some Titans noisy.
I've taken this as 'Cured'. Greg suggested the problem as being self generated static and recommended I take my shoes off.
it worked, suggesting that it wasn't static arcing from the TC to me but very much the other way round. Fixated as I was on 'the machine' I didn't reason it out. The reason I was getting such a reaction was that the earth is very effective, from the top plate down a back pillar through the earthing strap to the PSU and then down the power cable Earth.
I'd also forgotten that a Core XY printer uses both X and Y motors for any change in the XY position, where a Cartesian Printer is isolated in X or Y. If one motor isn't pulling its weight, the other will see the drag as potentially a stall (and the config I downloaded has a number of notations where DC42 had made variations from the 'standard' values in the config.g example. The 'Homing buttons tend to bang into the end stops and I haven't yet tuned stall detection.
Yout trigger heights look very high too. Please check that the two white IR LEDs and the black phototransistor at the bottom edge of the bard are not contaminated with filament or anything else. You can clean them using a cotton bud moistened in isopropyl alcohol.