Check the main fuses and also the battery wires. The pop was either a fuse blowing or an electrical arc (spark across an air gap) The smoke you mentioned makes me think of wires near the battery. It would take a huge discharge to make a pop and smoke from electrical stuff usually comes from burnt wire insulation. My quick guess would be a loose battery wire arced and singed a bunch of insulation. Now its connected but there is probably some carbon buildup and if the wire is loose you won't have efficient power flow hence the dim lights