Omnichrome 100 HeCd power supply info

Ok, so there are two different models, most know this. The a model is for the 39 and 56 models and the B is for the 74 model. I've just recently discovered an unknown C model. Mostly the only difference appears to be the ballasts as far as I know. The A model has 2 huge 10K 50W resistors. Does anyone know what it is in the B model? It's the large resistors in the back by the fan.

Thanks!