[Vlad95]

Thanks RpdB
I don't think there's much difference with interstage transformers of different models other than dimersion. But I try to localize the problem internally first.
In my experience, the most common cause of thin wire breakage is corrosion at the solder joint to the output wires or lamellas. These terminals are usually on the outside and can often be found and repaired.
Also, I'm not sure shipping to Canada is easy. But if I did not fix it I will contact with you about transformer.

Arran, yes, finally if I did not get fixing result I will look on market for transformers.