Root's 1969 Zenith 14Z8C50 Restoration & Troubleshooting Thread (Help Wanted!)

[videoroot]

Hey everyone! I'll go ahead and get my question out of the way first. If you wanna read more background info, I'll leave that for the end of my post.

The "horizontal output efficiency coil" on my 1969 Zenith 14Z8C50 is currently detached from the chassis. Over the years the plastic has just grown brittle and shattered. See the link below for photos of what I mean. In my (uniformed) opinion, there are two ways I could go about fixing this: I could replace it or just hot glue/epoxy it back in place.

The manual doesn't seem to give me any more information on what the coil is (are all coils the same? I have no idea). Its part number is S-77975. There's one for sale on eBay on the moment, but that also doesn't say anything more about what the coil is. Furthermore, eBay isn't listing any previously-sold units for viewing and Google isn't helping either. Any idea as to what I could go about replacing this with? If the damage is just cosmetic, would hot glue/epoxy be a good enough fix? Thanks!

Here's some photos of the damage: Click Me!

Some background: I got this old Zenith console back around new years after deciding I wanted to try restoring one. I have a soft spot for these old all-in-one tv/radio/record player consoles and for all sorts of old tech in general. I hope to eventually get this set up in my living room. I don't watch much TV, but this should be fine for my purposes.

I knew the TV part of this all wasn't working when I got it. The original owner's son, whom I bought it from, made it seem it was last working sometime before 2010 (at least their dad was last trying to find a repairman who'd work on it around then). The radio section had a few newer parts in there as well, so it's possible someone touched the TV section also at some point in its life. Like many of these old units though, it's gonna need work. I doubt the coil alone would be the sole reason it's not working, and that's fine with me. I really enjoyed working on the radio section, so I'm eager to start on this eventually as well.

With all the tariff stuff going on, this has sat on the back-burner since then though. I was hoping this all would sort itself out by now, but that doesn't seem to be the case. What's more, I have a couple different electronics projects all on hold at the moment, all of which need some parts ordered. I figure one of these days, I'm just gonna give in and order them all anyways, hence why I'm finally getting around to making this post here.

In the meantime though, I picked up a scanner from a family friend. Once I get that working, I'm gonna scan the three service manuals that I have to share with you all.

Hoping to use this thread as a centralized location for all my repair questions and progress updates. Hopefully doing so will make it easier for future visitors with the same unit to get help on their repairs too. Thanks for checking this out!

[zeno]

For your coil rewind it on an old form from a junker thats not dried up.
Use the old slug. Not perfect but will be close enuf. Adjust it per manual.
If you dont you risk the hoz out tube ( 6LB6 ??) overheating. Its an expensive tube.
Good luck
Zeno
LFOD !

[old_coot88]

It's also called the 'horz linearity' coil. If you're lucky enuff to find an NOS replacement, by all means go for it! When replacing it (or doing a rewind), it MUST be 'dipped', that is, tuned for lowest cathode current in the horz output tube. You open the cathode leg and insert a millimeter, and tune the coil for the lowest 'dip'.

Failure of this coil was the Achilles heel of Zenith color sets, with the exception of the old roundies which used a brown phenolic form that wasn't prone to cracking. I would never buy a Zenith without first ascertaining that this coil is intact.

[Electronic M]

Originally Posted by old_coot88

It's also called the 'horz linearity' coil. If you're lucky enuff to find an NOS replacement, by all means go for it! When replacing it (or doing a rewind), it MUST be 'dipped', that is, tuned for lowest cathode current in the horz output tube. You open the cathode leg and insert a millimeter, and tune the coil for the lowest 'dip'.

Failure of this coil was the Achilles heel of Zenith color sets, with the exception of the old roundies which used a brown phenolic form that wasn't prone to cracking. I would never buy a Zenith without first ascertaining that this coil is intact.

I've got enough spare Zenith convergence boards that use coils that use the same form that I'm confident I could strip the winding off one and wind the line coil onto a replacement form.

[Doug]

Are there any crosses to merit or others?

[old_coot88]

I've never done it, but wonder if an RCA type of horz.lin coil has the same inductance and would work if adaptively mounted.

[videoroot]

Thank you all for your suggestions! Sorry for taking so long to get back to you too.

In additional to all that you've shared, I've been considering attempting to 3d print a replacement as well (3d printing just so happens to be another, new hobby that I already want to start working with). Anyone know if this is even technically feasible? Surely, someone must've tried it, I figure. I may try it regardless, provided I can somehow verify it won't harm any other components in a circuit. I'll figure out the details later and share them here...