[Vlad95]

Thanks RodB for the help.
But this is not a real solution to this situation, not even a temporary one. Because the first output stage will only work in single-ended mode, not in push-pull. But the output voltage setting of the tube is in "B" mode, and you need to change the grid voltage setting to switch to "A" mode. Otherwise, the audio output will be heavily distorted and very low power. And only one of the two tubes will work. In other words, it will cause more problems than it's worth.
But in any case, the output transformer is also dead and needs to be rewound or replaced. So I still can't revive the radio this way, even temporarily.