Zenith Advanced System 3 picture tube testing

[zeno]

Nice work ! Nothing wrong with that CRT, the purity is
off a little on the bottom right, see if a little magnet on
tape fell off the CRT bell & is laying on the bottom.
Beyond that I would leave well enuf alone.

73 Zeno

[duckland 23]

Good job fixing that television you saved it from the scrap yard . That's always good when People care to fix a television and not buy that Chinese flat panel junk that breaks after 3 years or right after the warranty from the manufacturer .I always thought Zenith was a very High End set , But I also Like Sony Trinitrons Televisions . I got A 40 Inch set for free from a guy in Waukegan .Illinois that Didn't want to fix it . I need the famous Mz3001d chips in her . But the set is working Not and has been turning on and not giving me any trouble knock on wood .I have the chips and if needed I can replace them now .

[Kevin Kuehn]

I've started to notice some light-dark horizontal streaking in the picture. Also some light green retrace lines are visible when the set is first turned on, as well as the screen collapses to a green dot when powered down. So it seems there may be some heater to cathode leakage after all. So far I haven't been able to capture the green retrace lines on camera, only the light-dark streaks. What do you guys think?

[duckland 23]

You have directv hooked up to it . My Sony television will do the same thing too . Try a dvd player and see how the picture is . Im betting it one of your coax cables causing that bad picture or something in the tuner getting the signal . Check your cables

[Kevin Kuehn]

Actually it is a DVD player with separate RCA audio and video cables hooked to the TV.

[zeno]

An odd symptom. If it comes & goes try light tapping
of the CRT neck & see if it flashes. Can also swap the
transistors around & see what happens. Also run your tester
up a little on the filaments & see if it smokes out leakage.
Try it at 8V. These sets did some strange things when the
CRT's were bad.............

73 Zeno

[Kevin Kuehn]

Whatever it is it likes to manifest itself on mostly light blue screens. The moire effect makes it a little tough to see below. The color rendering looks great to me. I'll try testing the CRT again later.

[Kevin Kuehn]

More pictures...

http://i452.photobucket.com/albums/q...ps91760968.jpg

http://i452.photobucket.com/albums/q...ps178f8654.jpg

http://i452.photobucket.com/albums/q...ps505032fb.jpg

http://i452.photobucket.com/albums/q...ps814fa621.jpg

http://i452.photobucket.com/albums/q...ps15b27b4a.jpg

http://i452.photobucket.com/albums/q...ps4ac0770b.jpg

http://i452.photobucket.com/albums/q...psdd1916eb.jpg

http://i452.photobucket.com/albums/q...psdbda94d2.jpg

[zenith2134]

The minor purity issue really isn't showing too badly on a red raster. It's a non-issue from where I'm sitting. Usually the red raster is the one to exploit 'impurities' in the crt setup.
One of my neighbors still uses this exact type of system 3 on cable. I don't recall there being any problems with it. I believe it was a 1992 model.

[zeno]

You caught an awesome example of moire, best ive ever seen.
The Zenith folks described it as looking like a finger print
when we first encountered it on the old 14" tube jobs. We
had someone with a new 14" Zenith we sold bring one in for it.
After that it could be spotted in other sets even much older
ones.
One things for sure, all 3 guns have great emission. Like I
said these jugs did odd things when bad, you couldnt glance
at them & say "bad CRT" a lot of times. Sometimes it was like
someone was in back changing the grey scale slowly so
you couldnt do a set-up. Good one minute & bad the next but
not by much.
For the purity take a little magnet from a junker, put it on
the corner of the bell. Slide it in & out & rotate it for good
purity, works most the time.

73 Zeno

[sampson159]

i have a working chassis for that same set.sold the crt to another aker.it was excellent.this one looks good too.love that movie!worlds fastest indian.in my top 10 of all time

[Kevin Kuehn]

I had a friend stop in today that sold these sets back when new. He thought the picture looked fine, and that the horizontal shading effect was normal for these CRT's. Some side effect from the shadow mask he thought. Unfortunately I never really payed to close of attention to how the picture looked back when my folks bought it, so I have no clue if that makes sense or not. I sure don't recall seeing any other color set do this though.

Samson, I agree The Worlds Fastest Indian is a great movie.

[Zenith26kc20]

make sure the screen control on the flyback is not too high. It can cause the tracking to get squirrelly if it is too high (look for retrace lines with the brightness and contrast at minimum. If you see retrace it is too high. If too low, it may not track the black and white properly.
Good job on the cap replacement! You are a patient person to dig all of the "fish oil" caps out! Don't you love the smell when you are unsoldering them?

[Electronic M]

Originally Posted by zeno

You caught an awesome example of moire, best ive ever seen.
The Zenith folks described it as looking like a finger print
when we first encountered it on the old 14" tube jobs. We
had someone with a new 14" Zenith we sold bring one in for it.
After that it could be spotted in other sets even much older
ones.


73 Zeno

So that is what it is called! My 23" 1971 CCI hybrid does that only to a much more tolerable extent. The moire tends to shift around quite a bit, and produces some cool moving effects when I connect a video camera to it and create a feed back loop by pointing the camera at the screen...

[Kevin Kuehn]

Originally Posted by Zenith26kc20

make sure the screen control on the flyback is not too high. It can cause the tracking to get squirrelly if it is too high (look for retrace lines with the brightness and contrast at minimum. If you see retrace it is too high. If too low, it may not track the black and white properly.
Good job on the cap replacement! You are a patient person to dig all of the "fish oil" caps out! Don't you love the smell when you are unsoldering them?

Thanks!

Yes that smell is very nasty. Seems caustic in nature and I suspect it's not good to breath.

Turning up the screen(G2) control produces green retrace lines, advancing further and the screen washes out towards green. Possibly the horizontal shading(stripes) are the result of it attempting to blank the retrace lines under certain scene conditions?