Followed those 3 bullets "

[_] An invalid node connection or parameter value, resulting in that value returning as 0/black.

[_] No backdrop (skydome, etc) for reflections to "see", so you get nothing/black.

[_] Insufficient number of transparency bounces and/or transmission bounces (for refractive glass), resulting in an incomplete raytrace."

Looks okay now. Was a nod "Fresnel" connected to "Fac". Delete that for light bulb. Now, will try "seachnasaigh", render settings.