You're far more likely to find the entire power board OR the entire product as salvage and pull the power board or just transformer (since the transformer itself is an unlikely failure point) out of it.
I second duke37's question, what led to the conclusion that the transformer failed, how did it happen?
If all else fails, you could substitute a different power board with the same voltage and equal or greater current specs, and if it doesn't have the minor (lower current and voltage) power rails then you can take those off the output of the major power rail voltage.
If it is not required to have the replacement PSU be contained within the original product then it becomes even easier to source a PSU for a tethered-brick arrangement where the replacement PSU is external to the product.