Repair diagnosis for cdp with humming tranny

Raysonic is long out of business and doubtful there are any parts available for them.  Perhaps check ebay?

Transformers hum because they DO. Loose windings, poorly made, nothing really can be done electrically. but you might try tightening up the frame of the transformer. even adding clamps to the frame (if you can) or isolate it. Rubber under it, around it. Seal just the transformer in a canister somehow. or just dampen it with something pressing physically on it.             
How hot does it get is the only reason to back off on dampening material.Even Blu Tack type putty added around it. Polyurethane for bathroom cracks outdoor cracks.. But that stuff is permanent. So be sure it ain't gonna over heat before you glop it up with polyurethane.  
I could see making a card box to fit over it, fill it upside down with transformer in the polyurethane, let it st a week. peel off the card.

Just teach him the lyrics.