# How to fix ngspice simulation of Cree XLAMP CXB1507

I'm trying to simulate the 36V Cree XLAMP CXB1507 (spice model) using kicad+ngspice.

When I try simulate it gives the following error:

.model cxb1507 36v d is=6.15257e-19 n=32.22321 rs=9.82504 xti=1282.00581 ... Unknown model type 36v - ignored

If I delete the 36v in the spice model the simulation runs, but I'm not sure if it's accurate.

Aplologies if this is simple/obvious, I'm new to circuit simulation.

The .model card has this syntax: .model <model_name> <type> <parameters>. In this case, the model is CXB1507, the type is a diode (d), and the parameters are the list that follows. 36V is not part of the syntax, so it's discarded, or gives an error. It's safe to remove that since it looks like it's meant to be a tag-like notation. Or you can add an underscore between the model and the offending characters, and it will count as a single model line: CXB1507_36V (don't forget to rename the diode using that .model, too).