VFD display only working when bent?

[coppercone2]

So I have a old sony audio thing I wanted to fix with a VFD on it. It's 90's tech and I got a new one now that looks similar, but the problem with the old one was that it was only working when I pushed the front panel in

When I took it apart I redid all the solder joints in the area and some of them in the VFD made quite a bit of noise when they were soldered (like tension being reliefed), but afterwards it would not work at all, before it worked with mild pressure)

I threw it out (I don't need 2, the new one is better), but can those complex VFD displays get bad bonds in them that can lead to this symptom? I figure its pretty stiff because its a glass tube but its also thin and long so I don't know if it can be bending inside.

Basically it was a job that I set out about 2 hours for before its not worth it and that time expired, so I will just take the transformer and anything interesting in there

It was making ALOT of noise considering it was just joints being remelted (it almost sounded like tiny tiny wire snapping) so I figured for the 50$ it is on ebay, if I ever want one I can just buy it. It sounded like pink pink pink, you can imagine it sounding like a tiny suspension bridges wires popping off, at least thats what I imagined, it seems like a very bad noise to hear around electronics, because I resoldered big ass chips (dip 80 I think) before in older equipment from the 80's and I never got that kind of noise even though they are similar size. like the noise you get in a movie with water pushing out rivets in a submarine or something big on a wire bridge or something like that, very dramatic

[helius]

The (directly heated) cathodes in a VFD are "tiny wires" suspended from fingers at the sides. It could be that they snapped when you reflowed the pins, check with a flashlight if they are still there (every pair of fingers will have a wire across the panel).
The other possibility is that the vacuum seal was broken, look at the blob(s) in the corner of the front glass, those are barium getters that scavenge gas molecules. When the vacuum is broken and air gets in, they turn from dark silver to white.

[coppercone2]

ah I will see if I can look at the tube sideways before I throw it away, the transformer is more useful then the whole unit to me right now... i think the new ones have 24bit DAC and some other nice stuff.. its a sony receiver

I think it has 3x power op amps too