Virus or bacterial infection?
 

My oncidium has these black spots and yellow areas. Could it be a virus, bacteria infection or sun damage? I’m somewhat new to orchids. I have 3 phals that I received as gifts in 2018. But, this oncidium is a first for me. I got it from a friend that was “splitting” her big plant.

Is there anything that I should be doing to treat it?

First, Welcome!

You can't identify virus by looking, only by testing. I suspect that it is a localized infection, maybe due to water splashing on leaves and getting cold. The dry brown streaks in the last photo likely sun/heat or cold damage. Oncidiums (and other thin-leaved plants) do tend to get "ugly leaves" pretty easily. I'd just keep an eye on it, if it doesn't spread it is likely self-limiting. I'd keep it away from other orchids for awhile while you're observing it.

Thank you for your reply. What exactly does “away” from other orchids mean? It is currently in my bathroom with one of my phals, but it’s several feet away. Is that okay, or should it be in another room?

If your space constraints are anything like mine, "not touching" is as good as it gets. Several feet, a bonus.

Welcome to the Orchid Board!

Many Oncidiums have a lot of small brown/black spots. Some kinds are more susceptible than others.

The transverse pleating and puckering in some of the leaves means the plant was not getting enough water when those leaves formed.

Any chance the white damaged area could have been caused by a cat?

Probably! The gal I got it from does have two cats. They have done quite a bit of damage to her other plants.