[mornflt]

I have found that the audio transformer in my Philco 49-607 is open. Are most radio audio transformers the same or will I have to find a match?

[morzh]

You will have to find a match.

There are universal ones with taps allowing impedance match, like 125 series.

[codefox1]

Agree, but just about any tube era transformer will work once set is otherwise fixed, maybe volume might be a little less if large mismatch, but for ordinary radios, no harm in t rying anything you can scrounge up. By the way, since you have nothing to lose, try opening up the "bad" one carefully and see if there is a faulty connection beween the windings and the leads. Happens a lot, easy to fix.

[morzh]

There is a risk to that though. Yes I've seen it happen a few times also, but this is mostly due to oxidation, when you see the green copper, and when you fix this, you cannot be sure the oxidation has not progressed beyond that point and won't break the wire again soon.
One hope is, the oxidation might be due to the flux residue, and so it is limited to the solder joint, but also might be due to moisture.