Do you have a ramps or a rambo? If you want EXTRUDERS=1, then you’ll need to change the pins in the pins file. If you look at your pins_RAMPS.h in your 302 version, you can see the juggling it did, and it added an E2.
Ramps (well, MKS GEN L, but the same thing). I thought I compared that file and didn’t see much of a difference. But maybe I didn’t. I’ll take another look.
You should see the pins on E0 set to 70 and then a new E2 set to the pins from E0. You can make those changes yourself, if you find the right pins file.
So I notice E1 is different between them. So should I leave E1 alone in 425D, move E0 to 70 and E2 to the E0 pins? Or make E0, E1, and E2 all have the same assignments from the 302 version?
So, by doing it this way, did you disable the runaway and other heater safety features? It seems like Marlin would be angry that it wasn’t heating up… Oh wait.
Because the dummy thermistor is set to 170C, so it thinks that is the temp. So long as 170C is close enough to the set point, it won’t know the difference.
Both. Dummy thermistor set AND thermal runaway disabled.
Changes to the pins file made. Extruders set to 1. It compiled with no errors. I’ll flash it later today and see what happens. Once again, thanks so much for the help.