I have a second-hand Vertex with two extruders and extruder 1 (on the right, if you’re facing the printer) refuses to get hot.
The red LED that normally demonstrates that the extruder is heating does not come on.
It’s not sending any errors.
I thought it might be refusing to work because of a busted thermistor and no accurate temperature reading, but it seems to be reporting the temperature correctly - I blew some hot air over it with my heat gun and it reported the temperature increasing.
Everything appears to be wired up correctly; it spontaneously stopped working overnight after being totally usable.
Extruder 2 works fine.
Can anyone suggest next steps to diagnose the issue? Does the LED only come on if the heating element is OK?
Thanks in advance.