I don't have specific advice to give you. But a few of the videos on the Posy YouTube channel are highly relevant. He has fixed some vintage HiFi gear displays.

I don't have specific advice to give you. But a few of the videos on the Posy YouTube channel are highly relevant. He has fixed some vintage HiFi gear displays. Not in depth technical in the videos but maybe he has a community or something? EEVBlog forum would have knowledgeable people too.