Zenith 16D25 Keystoning issue

[sambo521]

Morning all,
I have successfully awakened my old zenith. really looks good for its age.
vertical linearity is a little weird and horizontal linearity is a tiny bit off but the biggest issue is fairly bad keystoning on this rig. Everything seems to check out electrically and i don't see any smoking gun.
I suspect the yoke and or magnets have succumbed to age and is distorting the image. Granted back in 1959 you didn't have 16:9 transmissions and scaling so this may be normal for this simple set.
I haven't tried using stick on magnets yet to see if that would help but i wanted to show you guys what it looked like and see what you think.
Thanks
http://www.videokarma.org/attachment...1&d=1629899950

[Notimetolooz]

It's a bit hard to tell from the angle of the picture and the reflection, but I don't thing this is keystone.
Looks like the geometry is off though so it probably is something to do with the yoke position or correction magnets.

[sambo521]

I called it keystoning or it could be called pincushioning but the only adjustments for this on b/w sets is the yoke magnets and centering rings, at least if I remember my theory correct right?

[Yamamaya42]

If it is anything like what is seen here on my arvin model 5204cm,

https://i.imgur.com/NBLz7Zf.jpeg
then the 2 things on the side are for Pincushion adjustment and as stated, the rings for centering.

[zeno]

It is hard to see in the pix
I dont see any classic keystoning like from a bad yoke.
First try just NO signal on the TV & see if the screen is full
of snow.
BTW Most B&W Zeniths have what is called either a width or lin sleeve.
Its a thin sleeve between the yoke & CRT neck. Its for fine adj.
Lazy techs sometimes through it away to get a bit more width.
Set will run fine without it.

73 Zeno
LFOD !

[Electronic M]

Definitely turn up the brightness and remove signal and see if the whole screen illuminates...It looks sort of like it will based on your picture.

If you are watching that image over the air/over a subscription service what could be happening is the show is 4X3 but the station wants to transmit it as 16X9 so they accomplish that by pillarboxing it (adding black bars to the sides of the transmitted picture. Most DTV tuners and cable/sat boxes that support analog TVs will take what the station sends as a 16X9 signal and letterbox it (add black bars above and below the transmitted picture) to make it fit the 4X3 TV....When both letter boxing and pillarboxing get applied to a 4X3 signal before it reaches a 4X3 TV you end up with a small picture with a black border all around. (I've seen it where both letter and pillarboxing were applied more than once in the commercials of a cable TV system and the commercials were TINY little squares 1/4 the screen size).


The solution is to go into the menu in your DTV box (or whatever it is) menu and select CROP instead of letterbox.



There may also be geometry issues (you really should get a test pattern generator or DVD to make the extent of the issue easier to visually quantify ) but others have already fielded good advice.

[sambo521]

I have full screen but the picture is still not square, and the sleeve is missing.
I believe that I will live with it as it will be probably sat aside now that I'm done with it, may make a shop tv out of it, don't know yet.
Guess its been too long since i worked on these things but I don't recall a sleeve but then again its been 40 years since i touched one of these things.
Thanks

[kramden66]

This set has the two metal t bars on the sides of the crt near the yoke ? They might control that bending issue on the side , I see it on the left of the screen

[djski]

Side pincushioning. Could be a capacitor.