[Vlad95]

Today I tried to restore the output audio transformer. The primary windings were completely open. Usually in 50% of cases, in my experience, such a problem is a consequence of corrosion of the soldering points of the primary wires with the output terminals or wires. Usually the ends of the windings are brought out to the outside of the coil, and not inside (in this case, only a complete re-winding can help) and already from the outside they are soldered to the terminals.
Okay, I'll try.
First, I disassembled the transformer and removed the top layer of insulation.

   

Yes, I was right. The soldering points are completely eaten away by green copper corrosion. New additional connecting wires were created for soldering the very short remains of the ends of the windings.

   

   

Soldered them all

   

   


And ...
Yes, now they are not completely open, but the resistance is about 200 kOhm - 1 mOhm.
In any case, apparently, there are corrosion breaks inside the windings. There was no easy way. More brain-twisting and headaches will be required.
Fun continue.