So, what did Zenith do to make their CRT's fail quicker?

[MRX37]

I think we all know that in the early 1990's, Zenith decided to make their CRT's last only about ~3 years before becoming too dim or failing outright. What I've wondered is exactly how they went about doing this? Did they use less emission materials in their color guns? Did they use under rated color guns (Like color guns meant for a 19 inch TV put into a 27 inch CRT)?

I've heard that weakening the vacuum in a CRT will make it fail quicker. Could this be what they did?

[zenith2134]

I doubt it was done deliberately!

Once heard that LG (or Goldstar in its original manifestation) sabotaged a batch of their CRTs. Of course, they took over Zenith soon after, and stopped providing buybacks of the modules and other Zenith practices.

[Carmine]

Originally Posted by zenith2134

I doubt it was done deliberately!

Once heard that LG (or Goldstar in its original manifestation) sabotaged a batch of their CRTs. Of course, they took over Zenith soon after, and stopped providing buybacks of the modules and other Zenith practices.

You would be amazed at how many people believe manufacturers build things to "fail" at some pre-determined date. You'd think they'd be laughed-off like Elvis sightings, but sadly, no.

Now it's quite possible that somebody said "We don't need this much vacuum" or "This cathode would cost $.0003 less if we made it thinner" etc. But a "goal" of early failure? No.

[MRX37]

Originally Posted by Carmine

You would be amazed at how many people believe manufacturers build things to "fail" at some pre-determined date. You'd think they'd be laughed-off like Elvis sightings, but sadly, no.

Mmmmm hmmmm...

I fixed a car door that fell off because the bolt between the two hinges had been designed with the center much thinner then the rest of the bolt. There was no reason I could find for this choice in design, other then eventual planned breakage. A 25 cent bolt from the hardware store fixed that, and it's still working fine. Lord knows how much the dealership would have charged, and they would have of course used another bolt designed to fail after a few years.

More on topic: pre 1992-1993 Zenith CRT's are still for the most part going strong nearly 20 years later, yet those from 1993 onward are weak and dim, if they're still functioning at all.

I wholeheartedly believe modern products are designed to fail after X amount of hours of usage. I've recapped lots of motherboards with caps that decided to fail right around the time when a new upgrade became available (sometimes as early as 6-8 months)

[Carmine]

Originally Posted by MRX37

Mmmmm hmmmm...

I fixed a car door that fell off because the bolt between the two hinges had been designed with the center much thinner then the rest of the bolt. There was no reason I could find for this choice in design, other then eventual planned breakage. A 25 cent bolt from the hardware store fixed that, and it's still working fine. Lord knows how much the dealership would have charged, and they would have of course used another bolt designed to fail after a few years.

It's tough to figure out what you're talking about, but it sounds like you are describing a "hinge pin", and the reason it was thinner in the center was likely because it was worn out! Is this the $500 T-bird you're always griping about?

As to the CRT failures, it's quite likely they made a production change for one reason or another (either cost, production speed, or new material) and it didn't go so good in the long run. Happens all the time.

Seriously, what kind of sense would it make to purposefully design a CRT that fails after 3-years? Not very likely you'll get a return customer!

You think a conspiracy makes more sense?

[MRX37]

No, the hinge pin didn't have wear on it. First off there was nothing to contact that area to cause wear. Secondly, the pin had a light coating of paint, and none of that was worn away.

I think you're being sarcastic, though it's hard to tell.

[MRX37]

I also remember reading on the repair FAQ website that someone from Thomson said their CRT's were designed to last around 15,000 hours. With a year being around 8000 hours, one of those 15,000 hour CRT's might last around 6 years if watched for maybe 8 hours a day, and by then of course something new would be out with all kinds of new features.

[andy]

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[Carmine]

Originally Posted by MRX37

I think you're being sarcastic, though it's hard to tell.

No, I'm not being sarcastic. But who cares? You've got your smoking-gun, er..uh "bolt", as evidence of the plot for unjustified failures. For some reason, your conspiracy theories about things you have no background in, irritates me.

I should get some sleep.

What year was this automobile anyways?

I'm sure someone will soon arrive to explain how Zenith decided it would be in their best interest to design a CRT that fails in three years. Or maybe you'll accept the idea that it was simply a bad design that didn't reveal itself until it was in the field for a while.

[David Roper]

My System 3 27" set mfd in 1996 has had as much use as you would expect a primary set of 12+ years to have and is bright as the day it was delivered. I guess it failed to fail.

[radiotvnut]

Originally Posted by David Roper

My System 3 27" set mfd in 1996 has had as much use as you would expect a primary set of 12+ years to have and is bright as the day it was delivered. I guess it failed to fail.

There's a slight chance that your tube was made by someone else besides Zenith. I seem to remember seeing a couple Zenith's from this period that used the bonded yoke style CRT's like what Thomson/RCA used. Some of the last Zenith CRT sets used Philips CRT's. Or, maybe Zenith "screwed up" and actually made a good tube. It happened once in a blue moon.

[zenith2134]

LOL

Reminds me of an album by 80s band National Pastime called "Built to Break"

Anyway, again not likely they did this on purpose. But slip-ups do happen when designing a product, and its quite possible that these faulty tubes were indirectly a result of cost cutting.

Cars are a different story though, and a pisspoor example IMO..... Different price point, different use, different MTBF and a hell of a different principle of operation.

Any manufacturer who knowingly markets a crap product that they know will die before it's out of warranty is a thief IMO. This is the main reason why I stopped shopping at Target, Walmart, etc.... its all shit.

[radiotvnut]

Originally Posted by andy

I've heard various stories about contaminated materials and components used in the guns, but nothing certain. Those CRTs didn't really wear out, they failed. They almost always had shorted guns, or low emission on one gun. I only saw a few that were just weak with no other failure.

I heard somewhere that the aquadag coating inside the tube would flake off and make it's way to the electron gun, causing it to arc/short. As far as the low emission, who knows?

A warning to any "newbies": If you find a '90's Zenith with a shorted voltage regulator, fried resistors, and a blown apart driver transistor in the power supply; just go ahead and trash it. There's a 99% chance that the CRT arced and did it. A shorted CRT can also take out the video driver transistors. I'll never forget the first set I found that suffered from that condition. It was a two year old set with no green. The green driver transistor was leaky. I soldered in a new one and was greeted with a nice picture. After playing it all day without problems, I sold it to a friend. Two weeks later, the set came back to bite me in the butt with a "no green" condition and a blown green driver transistor. Turned out the CRT was the culprit. Back in the '90's, I was getting bad CRT Zenith TV's by the dozens from the local dealer. Many were only 2-3 years old. Heck, I've seen Zenith's right out of the box that looked like the CRT was shot.

[MRX37]

I could see a design goof up if the bad CRT's from Zenith stopped shortly after 1992-1993. However, this continued throughout the rest of the 90's at least. Every 1990's Zenith or Zenith made TV I've come across had a weak CRT in it. The one exception was a 27 inch Sentry 2 from 1992. From 1993 onward: bad CRT's, and not just the 27 inch ones. 19 inch CRT's, and even 36 inch CRT's... all weak.

Also, not too long ago I found three JVC TV's from around 2003-2004. not only were the CRT's shot, I couldn't adjust the G2 voltage to brighten the picture very much. The flyback's themselves had something inside them limiting how much the knob could turn. I could turn that knob maybe 1/4 of a turn in either direction.

Finally, A Philips TV from 2005 that i worked on had a "feature" to make it shut down if the screen was too dim. That sure as hell wasn't a cost cutting measure!

EDIT: Also, if a company is trying to save money, why not take a reliable design and stick with it for as long as possible? Why spend the money designing a new chassis and CRT every year? Change the case and update the look/features, but keep the important internal electronics the same.

[andy]

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