Cracked flyback core?

[metertech58761]

So, I have a vintage 1980 'dumb' terminal that was adapted for use by the deaf in talking to each over a landline.

The core technology was developed by Micro-Term of St. Louis, but I do not know if these were assembled by them, a subsidiary, or sold as kits to the company that made these terminals.

ANYWAY, these terminals used pre-assembled CRT modules built by Zenith - they have an edge connector on its main board.

Pretty straightforward; it just needs +12, ground, H & V sync, video, and brightness pot.

Thing is, all but one of these I've seen over the years has had the nuts on the clamp U-bolt torqued down JUST a bit too much to where there is a visible crack in the ferrite core.
(the one I currently have, has two)

Depending on the location and severity of the crack, the cracked core manifests as anything from visible 'ringing' at the left side of the screen to severe horizontal foldover spanning a good third of the screen. This one is surprisingly one of the better ones; it merely has a bit of ringing visible. I should add, this was with it on for a few minutes; it occurs to me the possibility that the ringing would eventually erupt into full foldover if ran long enough...

Am I correct in assuming there is no 'magic' method to heal the cracks, and that if I monkey around with the tension on the clamping bar nuts I risk completely ruining the flyback?

Picture is of a terminal and spare module I had years ago. The flyback on the unit I have is mounted on the main plate, not up on the upright as in the picture.

[moffy]

Once it cracks it is never the same, perhaps some super glue if you can bond it well without air gaps and if you can relieve the mechanical stress on the core.

[Phil1977]

I´d use super glue only as a very last resort - if the glue fills up any crack then the ferrite core may be completely destroyed. As long as you just press the broken parts together and keep the gap as small as anyhow possible there is a better chance of keeping the magnetic properties in an acceptable range.

I had best experiences with tightly applied kapton tape. Maybe you can use glue on the outside of the tape to further stabilize everything.

[metertech58761]

I guess I kinda answered my own question... I see that the ferrites are partially potted into the flyback too. NUSPI. 

OTOH, the CRT is still good and may be of use to someone to "repower" a worn monitor.

Years ago, I had scavenged a good GREEN CRT (the bulk were the plain ol' monochrome ones) and an undamaged flyback I planned to put into one of these terminals.
Unfortunately, the museum was 'cleaned out' for move to storage before I could get back in to work on the terminal. 

Oh well - thanks for confirming my suspicions.