1967 Black and White Zenith tube tv chassis 13X16(Z)

[Lain94]

I now have my first ever Zenith Black and white tube tv to add to my collection. I have already recapped it, checked CRT emissions, tested all tubes, and did cleaning along with deoxit. TV was having arcing issues in the HV cage and I later found out it was due to secondary the two wire winding on the flyback having a hole punched through it from the HV leaking out causing the high pitched buzzing noise. Recapping did not fix issue, tried cleaning and using corona dope but no luck still, and eventually replaced flyback with NOS one and am going to further look at the old flyback and keep it for refurbishing as I do with any of these old parts. Nothing gets thrown away due to the rarity of these. Arcing issue now gone. Emissions of CRT are great! TV now works but I notice a brightish white vertical line in the center of the screen. Unsure of what may be causing this issue.

Chassis number is 13X16Z

Very simple to work on and much less complicated than the color tvs I have looked at in the past.

https://imgur.com/a/kL1cx76

[jhalphen]

Hi to all,
Hi Lain94,

Photos 1 & 2, Zenith B&W TV.
Photo 1 is a good TV picture.
Photo 2 shows the horizontal brightening.
Seems to be linked to the white text displayed.
AGC issue? what do the experts think?

Does audio buzz when text is displayed?

Photo 3, EHT & H Scan cage section.
Red anode connector wire seems to have a cut or brittle plastic breakup.
See zone highlighted by red circle.

Best Regards
jhalphen
Paris/France

[zeno]

In some pixs the HV cup looks quite messy & HV rect socket turning green.
The filament winding arc is common, replace with flexible 20 KV wire.
I see two pix of white lines. One hoz & the other vert. The kind
of problem that nobody wants, at least without a full suite of
test eqt. & tube collection.
Good little sets IIRC only built for a year or two.

Zeno

[Electronic M]

Originally Posted by zeno

In some pixs the HV cup looks quite messy & HV rect socket turning green.
The filament winding arc is common, replace with flexible 20 KV wire.
I see two pix of white lines. One hoz & the other vert. The kind
of problem that nobody wants, at least without a full suite of
test eqt. & tube collection.
Good little sets IIRC only built for a year or two.

Zeno

+1
I've replaced the 2 wire HV rect filament winding of the flyback and or the HV lead to the CRT on several sets. A good source is curb find 90s CRT sets. Whenever I see a curb BPC that's sat a few weeks (garbage men can't legally take them) without being rescued I steal the HV lead and a handful of other parts.

[Lain94]

Originally Posted by Electronic M

+1
I've replaced the 2 wire HV rect filament winding of the flyback and or the HV lead to the CRT on several sets. A good source is curb find 90s CRT sets. Whenever I see a curb BPC that's sat a few weeks (garbage men can't legally take them) without being rescued I steal the HV lead and a handful of other parts.

So the two wire winding is usually a pretty simple fix then? Sounds like I am better off replacing the wire in that situation as opposed to using lots of corona dope to fight with the old wire insulation. What is the gauge typically of this wire? Why does it seem to me that anytime I have had flyback arcing occuring in one of these old tvs, it seems to always happen from the 2 wire winding as opposed to the main rubber tire (that is what I call it, or if I have not had lunch yet a chocolate mini hostess donut)

[Lain94]

Originally Posted by jhalphen

Hi to all,
Hi Lain94,

Photos 1 & 2, Zenith B&W TV.
Photo 1 is a good TV picture.
Photo 2 shows the horizontal brightening.
Seems to be linked to the white text displayed.
AGC issue? what do the experts think?

Does audio buzz when text is displayed?

Photo 3, EHT & H Scan cage section.
Red anode connector wire seems to have a cut or brittle plastic breakup.
See zone highlighted by red circle.

Best Regards
jhalphen
Paris/France

Audio does not seem to be buzzing to any extent that I am able to notice even when audio is turned up a ton. No issue in that area, audio is pretty clear despite no work being done with tuning. I may attempt to fiddle with the AGC controls on the back more and see how this affects it. I was using VHF channel 4 and another time 6. Using one of those RF modulators that lets you choose a channel. Very handy for looking at UHF tuner I might add. Will take a look at red wire and follow up. Wouldn't be surprised though as the red anode wire is still original. I have some spare HV voltage anode wire I can replace with if needed luckily.

[Electronic M]

Originally Posted by Lain94

So the two wire winding is usually a pretty simple fix then? Sounds like I am better off replacing the wire in that situation as opposed to using lots of corona dope to fight with the old wire insulation. What is the gauge typically of this wire? Why does it seem to me that anytime I have had flyback arcing occuring in one of these old tvs, it seems to always happen from the 2 wire winding as opposed to the main rubber tire (that is what I call it, or if I have not had lunch yet a chocolate mini hostess donut)

Yes replacing the wire is better and easier...Just access the solder lugs on the HV rect socket, desolder the old wire, make sure the new wire makes the same number of turns around the flyback frame and solder in the new wire. Some techs will just delete the rect heater winding and install a SS tube replacement and I've had luck with that too.
I have no clue what the guage is (it only carries the rect filament current so it doesn't have to be particularly thick), but the insulation HAS TO BE rated at least 20KV (30KV is preferable) for monochrome and 30KV (40KV is preferable) for color.

The reason the filament winding arcs to the frame but the doughnut rarely does is that the frame is grounded and the filament winding has the full 8-25KV of the set on it with only one piece of insulation separating it from ground. The center windings of the doughnut have the lowest voltage on them (sometimes their grounded, but often their 100-450V above ground) so if the higher voltage windings of the doughnut closer to the outside have insulation failure they're usually more likely to arc to the lower voltage windings... Eventually creating a carbon track which eventually shorts out the flyback and kills it.

[Lain94]

Replaced old HV wire and anode those goes to CRT with new replacement. Sadly issues is still persisting. Straight white bright vertical line on crt that is mostly in the middle sometimes a bit slight to the left. A bit stumped on this one and annoyed after being so close to fully restoring. No other symptoms. Anyone have any idea what could be causing this?

[old_tv_nut]

A blurry bright vertical line near the middle of the picture may be due to a horizontal drive issue. Does the set have an adjustable horizontal drive coil? How about a horizontal linearity coil?