Block QNUMBERS in SPheno.spc file

[saiyad]

Pythia requires a block called 'QNUMBERS' which contains few quantum numbers like electric charge, spin, color rep., etc for BSM particles in the param card (equivalently the SPheno.spc.model_name), but in my case, there is no Block QNUMBERS in the spheno.spc file. Is there any flag to write these blocks in the spc file? If not, then what should I do to write these blocks in the spc file?

[MDGoodsell]

This is an issue I've come across too, and solved it indeed by adding the appropriate QNUMBERS blocks myself. You can copy and paste them from the blank param_card.dat that madgraph generates when you generate a process. Also, you should comment out the MODSEL block, otherwise pythia will just think you have the MSSM and set some default masses ...