ok... what you have there is a very pretty plant while blooming, nice orange/redish/greenish flowers. one of my faves. and one of the oncidiums that has given me some real trouble growing it. i keep mine in a south facing window. they do like a bit more light than phals. yours is very overgrown. it is growing in sphagnum moss most likely, the roots have just completely obscured it. which makes repotting very annoying. i have bought a few other oncids in this condition. i have never had one survive when i just stuck it in a larger pot and filled around it. your plant is basically 'mounted' but on a ball of moss. rotting moss most likely. i would try to pull as much out of it as you can from the bottom or by gently untangling the roots. you can soak it first in water for a few hours to loosen things up. and after the moss is removed, give it a soak in weak bleach water. it only takes like a teaspoon in a sink of water to sterilize, so not too strong is ok. the existing root ball has been growing on the moss-mount, up against the plastic pot. but that is still a huge amount of air to the roots. almost as much as being mounted in a high humidity place. repotting it could and probably will harm those roots somewhat. i would wait until those new growths are forming good roots, if possible. and perhaps place some pebbles or something in the bottom of the pot to prop the plant a little higher so those new growths don't get pinched. i have decided the next time i get one like this, i will gently untangle roots and remove the moss and try semi-hydro. another option is to remove the moss, make a moss-ball and do the same thing to it, using a slightly bigger pot. take the pot, cram it tight with the sopping wet moss, and allow to dry. it will form a brick. wrap the plant/roots around it and place back into the pot. mine has been very slow growing and fussy. but the flowers are beautiful. i have heard of others telling theirs was fast growing and sturdier. i may get another. mine was in rough shape when it arrived, wrinkly, and it took repotting harshly coming out of the moss to a bark mix.