If the yellow component is a Bourns MF-R185 PTC as I speculated, would these be the correct ratings of 1.85A Hold, 3.7A Trip and 30V max?
If the unit is used, as the OP may be implying, could it be that a previous owner installed it and left the original (possibly blown) fuse in place?
EDIT: The Bourns MF-RHT200-0 is a 2A PTC fuse and may be better suited for the Legacy Base2 transformer.