While inspecting the flyback transformer from my Predicta Debutante (10L43), I found a 1/4" or so chunk missing from one side of the flyback. It doesn't look burnt, it just appears that the rubber dried, crack and fell away.
I've read where guys have removed all of the rubber then sealed the windings airtight with silicon (I assume a high temp variant?).

Can anyone describe a good technique (assuming that this flyback is still serviceable) and what products you used? Thanks!

If it works I would leave it be.

Here is an example of flyback that works fine, not a predicta, but you get the idea.

If however you choose to redo the fly, I have heard that you have to be careful about what kind of silcone you use, to avoid chemicals in the product from attacking the fly.

From your description it does not sound bad enough to warrent fooling with.

I wouldn't be sure of which silicones to stay away from, but if you open the tube and it burns your eyes, that may be a baseline!

Flybacks are delicate as they are anyways and DaveWM brought up a valid point.. That one in the picture would have me wondering what to do though as it does make me cringe a bit!

Make sure Horizontal Output Current is in spec so that you can prolong the Flybacks' life as much as possible!

And even though I wonder if I did the right thing with mine I sealed it up but I used windshield silicone sealer. It's quite "liquidey" and will flow through the windings. I took the end of a plastic caulking tube (cut to size) and cut a slit in it for the plate cap wire. (fits perfect). I laid it sideways and filled one side and the next day filled the other. I did have to fill the slit area first to make a seal.

It's been working ok, made for a nice repair. As I've mentioned elsewhere, they do like to run on the warm side and it's temperature stays consistant if I have it on for an hour or two.

So, it's good to monitor it but I'd leave it for now. But this is a good topic to discuss.

how about a contest, your worse looking fly that still works :)

I have made my entry...Magnavox C36 chassis

Seems low priority to me. I have TVs with horrible looking flybacks that work fine day in, day out.

You can always revisit the issue after you finish restoring everything else. What is the state of the TV, otherwise? For example, do you know whether the CRT is dead or alive? I'd focus on making it work and worry about a little piece of insulation later.

Phil Nelson

Seems low priority to me. I have TVs with horrible looking flybacks that work fine day in, day out.

You can always revisit the issue after you finish restoring everything else. What is the state of the TV, otherwise? For example, do you know whether the CRT is dead or alive? I'd focus on making it work and worry about a little piece of insulation later.

Phil Nelson

I'll finish testing the resistors tonight, so far 7 are out of tolerance, I'm waiting on the caps & electrolytics to come in, and I do not have a CRT tester so that will have to wait until I'm ready to power up the set. I've just been addressing things I can do while I wait for the parts to arrive. The Army Post Office is sloooooow.

Here's a pic of the flyback. It isn't very bad, and when compared to the Dave's from his Magnavox, it's downright pristine :-)

http://i523.photobucket.com/albums/w353/chemo64/Predicta/Picture3-1.jpg

yep I would leave that alone. you dont want to mess about too much around there and end up breaking some fine wire.

you can check the windings for resistance while you're waiting. just be careful of that lead coming off the top of the fly going to the plate cap of the HV rectififer. I would not risk moving ANY wires around that thing esp since you dont know if its working yet.

That Fl y in the predicta looks like the added sealant has eroded away, the actual fly looks fine as the wax is still surrouning the core. Agreed, I wouldn't worry about it.
As well I am not seeing any goo arond the base of the fly either representing excessive current. You should be fine. If in question you can always test the HOT cathode current just for peace of mind.

Thanks fellas. I appreciate the advise and I will leave it as is. But there is a tiny bit of exposed wire where the wire for the HV comes out of the top of the fly. Should I try and cover this or not worry about it either?

leave it be until you get a chance to test the set to see if there is a HV problem. Try not to handle that wire to avoid breaking it.

That's a good lookin' Flyback! Least of your concerns..