Nozzle heat issue

[nic-roche 0]

Ultimaker Classic, w heated bed...

I have an unusual problem that has plagued me for days.

The observed symptoms are after a few layers the filament feed starts slowing to eventually no feed over one layer.

The temperature (on LCD) seem OK for Nozzle and Bed (245, 100) but as the nozzle travels across existing tracks it grinds through (not melts through), suggesting the nozzle temperature is incorrect. Looking at the filament at the feed mechanism shows a grinding of the teeth on the filament.

I have:

- changed Nema 17 motors (thinking the motor may have lost power)

- assessed and cleared extruder as functioning

- changed the circuit board on the hot end

- changed the K type thermocouple

I did not have a spare heater element to verify this part. Does it look like the heater element has gone? Why would the nozzle temperature be misreporting?

Thanks,

Nic