Last night my F1 Fuse blew during a print, reset and showed the typical 2000C. I've ordered some self-resetting fuses and plan to do that modification. However before doing so, I would of course like to find the root cause.
VSSA to GND is open, and the F1 fuse is too.
I've visually inspected all related wiring and cannot see any melted sleeving or frayed wires etc. And I've also done some resistance measuring and everything is within spec, results are as follows;
Hotend Thermistor - 123k
24V 50W Heater - 10.8
Heater lead to outer casing - 3M
Heater block to Thermistor - Open
Bed Thermistor - 129.1K
Bed Heater to Bed Thermistor - Open
I'm not sure what else I can check while waiting on the new fuses? And if I can't find the cause, what order of operations would you recommend for systematically testing? Attaching both thermistors and one other component at a time, and running, repeating until something trips? And if it doesn't, could this just be component degradation, or are their other failure modes that are not described in https://duet3d.dozuki.com/Wiki/Connector_and_spare_part_numbers#VSSA_fuse ?
Thanks for reading, and I hope that we can get to the bottom of this.