Thanks for your replies:
cabbage_breath: Yeah, that would definitely be a next step, but I was a bit reluctant to mess with the circuitry, lacking a system connection schematic. I found plenty of docs about the RAMBo, but perhaps I overlooked material that shows what’s connected to the RAMBo on the TAZ2. Such a document might usefully include brief advice such as equivalent circuits, e.g. “disconnect here, test with an ohmmeter, expect n ohms across A to B.” Did I just totally miss a document like this?
jebba: Thanks, that’s a wonderful offer. Glad it is not going to be necessary, as…
After some 7) head-scratching, I continued my trouble-shooting as follows:
- Eyeballed the termination at connecter X11, saw two red wires to that point stretched taut across the interior of the electronics box.
- Pulled the connector, loosened the 2 screws, examined wire stripped ends, re-seated wires, tightened screws.
- Tested hot-end. Hot! And OK in 2 following prints.
A potential intermittent open-circuit: the wire clamps at the X11 mating connector appeared to be clamped mainly on the insulation. Maybe that’s OK, maybe they are intended to clamp on BOTH insulation and stripped wire ends --I’m not familiar with these connectors – but in any case, re-seating the wires seems to restore hot-end heating. And restored some slack on those wires.
So… Problem appears solved. Thanks very much!