Welcome to the SeeMeCNC Community

So I have been using my ROSTOCKMAX v2 with my new HE280 for a number of projects over the past 3 weeks.
Probably put in 100 or more hours of printing with no issues at all.
All of a sudden, on my next print the hot end will not heat up.
When I manually adjust the extruder temp on the LCD panel, I can see the two red lights on the board start flickering
but the temp just remains at room temp.
The bed heats up with no issue.
I checked that the connector was plugged in properly and i checked and replaced the fuses just to make sure they were fine.
Wiggled the wiring around thinking maybe I have a loose wire but no joy.
Finally, I reset and reloaded the EPROM and it still will not heat up.
I do not even hear the fan load up slightly like it does when I turned the hot end on before the issue.
Any assistance would be much appreciated because we all know if a machine is going to give you issues, it will do it right in the middle of a project.

Thanks,
Tom

Did you check the thermal fuse in the heatsink of the hotend?

I did not.
How can you tell if it is bad?

One way would be checking it for continuity with a multimeter while the harness is unplugged.

If you remove the HE280's top cover (three screws holding it on), you can put your multimeter on the main + and - where the wires from the heater stick through the board. You can check these for continuity (should be a complete circuit and emit a tone) or resistance (3-4 ohms). If neither of those works, you've either got a blown thermal fuse or one of the ferrels that hold the heater wires together came loose.

If it's your thermal fuse, it blew because the fan on the heatsink wasn't running. When you turn on the printer, is that fan on the hot end running? Are there blue LEDs lit on the hot end when you turn it on?

Yes, the fan is running and the blue LED's are on.
I will check for continuity tonight.
Thanks.