96 25" Zenith TV that some how still has a good CRT

[liammc00]

Found this today at Goodwill for $2. These TVs have reputation for having bad CRTs. To my surprise that the CRT was still good for being a pretty high hour set. I did readjust the focus and G2. The TV is pretty low end set from Zenith as its RF only and mono sound. I'm currently using the tv in my bedroom for the time being. If this TV fails I won't fix it unless it's a cheap repair like a cap going bad as these sets have tubes that like to short and blow up the set or go weak way faster then it should.

[Yamamaya42]

Originally Posted by liammc00

Found this today at Goodwill for $2. These TVs have reputation for having bad CRTs. To my surprised that CRT was still strong for being a pretty high hour set. I'm using the tv in my bed room for the time being as I often swap out sets as I have many sets. If this TV fails I won't fix it unless it's a cheap repair like a cap going bad as these sets have tubes that like to short and blow up the set or go weak way faster then it should. Here is challenge and it is If you can guess what old 90s show I'm watching on this set from the picture below

what picture?

[dishdude]

They started getting better around '96. '93-'95 were by far the worst.

[Jeffhs]

Given the high failure rate of 1990s Zenith CRTs, I am amazed a few of them (1996 and beyond) survived this long (until 1993-'95, when the tubes strted failing again). I have a 19" Zenith color set, SMS1917SG table model, that's still going strong, including the CRT. The last time I tried it, several years ago, the picture and everything else were every bit as good as they were when the set was new. The TV is now in my bedroom and isn't used much (or at all, to be perfectly honest) these days except for an occasional test.

Heater-cathode electron gun shorts killed most '90s Zenith CRTs; these shorts often took most of the set's HV plant as well when they did, before or after blowing the HV fuse in the HV cage. Being Zenith, I would have expected these CRTs to last years or even decades without problems (as did earlier Zeniths), but I get the feeling by the late 1980s or '90s these tubes were being outsourced from foreign countries (!) and were no longer Zenith-built products, even though they may have had the Zenith label on the CRT bell.

[Pio1980]

A friend had a module era Zenith color port in storage, asked me to get it working again for nostalgia. Cleaned the troublesome module connectors and fired it up. Heard sparking as if in a bottle, the CRT had lost vacuum in the meantime. Dunno how common that is.

[Electronic M]

Originally Posted by Pio1980

A friend had a module era Zenith color port in storage, asked me to get it working again for nostalgia. Cleaned the troublesome module connectors and fired it up. Heard sparking as if in a bottle, the CRT had lost vacuum in the meantime. Dunno how common that is.

If the safety caps on these fail HV can climb over 100KV and heat the CRT till it cracks. Repair techs of the 70s modular era will tell you that it wasn't uncommon for it to saw off the neck and the yoke to drop off when that happened and the owner wasn't in the room to stop it quick enough...

[JohnCT]

Originally Posted by Electronic M

If the safety caps on these fail HV can climb over 100KV and heat the CRT till it cracks. Repair techs of the 70s modular era will tell you that it wasn't uncommon for it to saw off the neck and the yoke to drop off when that happened and the owner wasn't in the room to stop it quick enough...

I saw one like that. Most of those 4 lead caps shorted and killed the HV. The one that took the tube out also took the yoke and the vertical module. Zenith paid for the work even out of warranty.

Even though Zenith recalled the TVs, a lot of them back then weren't registered and the owners never got the notice. The vast majority of them never failed at all, but we'd still change them when they did show up.

John

[Pio1980]

Originally Posted by Electronic M

If the safety caps on these fail HV can climb over 100KV and heat the CRT till it cracks. Repair techs of the 70s modular era will tell you that it wasn't uncommon for it to saw off the neck and the yoke to drop off when that happened and the owner wasn't in the room to stop it quick enough...

I don't think in retrospect that was the problem with this set, no signs or smells of overheating or ozone production or anything else unusual other than the bottled arcing.
Still, good to know.

[zeno]

I worked most of my life for a large Zenith dealer. The really bad
ones were low end 19 & 25 " sets. Also there were 2 styles of chassii at the
time. A one board set & a 2 board set often with sub boards for special
uses. The 2 boards were high end & got good jugs as a rule.
Zenith did make good on piles of them for up to 5 yrs. But if you had
the cheapest 19" you got a free jug but for a short time. Labor was
often waved by the SELLING dealer. Big box sets were billed out at list,
Mom & pops were best as always. Low end sets NEVER got the 5 yr
extension on the CRT warranty. ( norm was 2 yrs CRT, no labor after 90 days ).

73 Zeno
LFOD !

[dishdude]

Originally Posted by zeno

I worked most of my life for a large Zenith dealer. The really bad
ones were low end 19 & 25 " sets. Also there were 2 styles of chassii at the
time. A one board set & a 2 board set often with sub boards for special
uses. The 2 boards were high end & got good jugs as a rule.
Zenith did make good on piles of them for up to 5 yrs. But if you had
the cheapest 19" you got a free jug but for a short time. Labor was
often waved by the SELLING dealer. Big box sets were billed out at list,
Mom & pops were best as always. Low end sets NEVER got the 5 yr
extension on the CRT warranty. ( norm was 2 yrs CRT, no labor after 90 days ).

73 Zeno
LFOD !

Now that you mention it, I did see a lot more of the BOTL sets with bad jugs than the higher end stuff.

[liammc00]

After using the tv for a while I have deaced to part it out do to the set haveing purity problems and awful convergence among other side effects of getting tired CRT. the purity makes all red look yellow from left to the middle of the screen. That tv is going to the trash and I will keep the main board and speaker everything else goes bye bye.

[jbattles]

you know that tube is strong. it just needs a setup just do a set up on it. convergence and purity is easy to do. the rings on the tube probably moved around from jarring the set. the glue that put on the rings is old. a setup can be done set the purity and convergence and the to keep rings from moving use finger polish. use any color you want and put a line along the rings from front of tube of to the end of tube and that will keep then in place. now just the just the rings try that before its condemned. i can tell from the picture your contrast is to low. brightness is to high grayscale is off need a little more blue. g2 might be to high and before g2 is adjusted grayscale has to be set first. that is the last of zenith before gold star came in, if that was the tube to short it would went in the a long time ago.

[liammc00]

Never seen this happen before as the plastic tabs that held on the rings have broken off which allowed me with no force to slide ring assembly off of the neck of the tube. so I guess that explains why the picture looked so bad and It also looked like they never glued the rings in place form the factory as I can't see any signs of glue on the rings to hold them in place. I'm going to try and glue it back on to the tube.

[jbattles]

you can use any ring from set a set that has 25" tube, if it fits the neck it should work. it gets really hot by the heaters and it bake the plastic. there were glued it probably fell off. its hard to believe, but that set is around 27 - 28 years old. hopefully you can replace the ring or maybe put that one back together. it will make a good picture.

[liammc00]

Well I got the ring clued back and redid the convergence to the best of my ability as I have never done it before and I had to use my Genesis with the 240p test suite as a pattern genturatur. I also put a new degusing thermistor with one out of a 27" 2004 funai chassis that I scraped for not having vertical and that fixed the purity porblem.