Ok I've been combing through the firmware and think I've spotted a potential problem. The comments on temp sensors reads:
1 : 100k thermistor - best choice for EPCOS 100k (4.7k pullup)
this is what was stock and what my extruder 0 runs
20 : the PT100 circuit found in the Ultimainboard V2.x
this is what I've been told to change to and what the e3d wiki says, but I was under the impression that the ultimakers didn't need the amp board to work. So does that mean this option should only be used on ultimakers?
There's also this:
* 1047 : Pt1000 with 4k7 pullup
* 1010 : Pt1000 with 1k pullup (non standard)
* 147 : Pt100 with 4k7 pullup
* 110 : Pt100 with 1k pullup (non standard)
Now I believe the 3 temp sensor connectors on the board (E0, E1, bed) are all 4.7k pullup, so could I use 1047 or 147 as temp sensor and plug the pt100 right into the E1 plug, without the amp board? I'd rather get it working the way I have it wired now, with the amp board and signal to pin A3.