Out of curiosity, Does anyone know the expected or average lifetime of a CRT before it starts to degrade?

Reason I ask is my daily driver in the bedroom which is actually now technically a "nightly driver" is starting to lose its "depthness" to the colors. its hard to explain. the picture is still sharp, but the colors are going.

Anyways, its a 1994 BPC era Magnavox 25" table set that I have had since new. When it was new, I watched it way more often than just nighttime as I was a kid then, but as I grew into an adult and it has moved with me a couple times, its just become a bedroom at night TV. I have seen this same chassis and tube used for late wooden floor model sets as well. Have serviced a few with the same common faults.

So doing the math at 10 hours a night every night since 1994 puts it around 87,600 hours. thats a ton! and thats not even accurate because if I would account as a kid its more close to 100,000 hours or so.

But I have had to service it a couple of times. the 100uf cap in the horizontal stage is known for failure in this model and it failed twice before I beefed it up, and then I had to change some caps in the STR regulator circuit along with the STR and its fuse.

its been stable for 12 years since that failure.

Just wondering what your thoughts are and how long yours have lasted? For my set being made in a BPC era, its incredible that its lasted this long and STILL running.

It depends on the quality of the CRT plant (cleanliness, degree of evacuation) as well as on the quality of the cathodes. These things varied from maker to maker.

IIRC, at one time (when viewing was mainly the three major networks), TV makers figured 2000 hours per year average use, with an average receiver life of ten years. Some of the crappier CRT plants (e.g., Admiral) would produce color tubes that had a significant percentage of failures in the first two years.

Also, consider some TV chassis designs drive a CRT very hard in the name of brightness and picture quality, Sylvania SuperSets being a major offender.

I was figuring with mine being in the black plastic crap era when zenith was failing like crazy that the life would be much poorer than it has been. Its just surprised me.

It depends on the quality of the CRT plant (cleanliness, degree of evacuation) as well as on the quality of the cathodes. These things varied from maker to maker.

IIRC, at one time (when viewing was mainly the three major networks), TV makers figured 2000 hours per year average use, with an average receiver life of ten years. Some of the crappier CRT plants (e.g., Admiral) would produce color tubes that had a significant percentage of failures in the first two years.

Wow thats a shame. My zenith has an admiral tube in it.

I was figuring with mine being in the black plastic crap era when zenith was failing like crazy that the life would be much poorer than it has been. Its just surprised me.

You said it's a Magnavox - Philips tube?

Wow thats a shame. My zenith has an admiral tube in it.

Depends on the vintage. IIRC the bad admiral tubes were mid 60's to early 70's...Also check the EIA code. Many tubes were labeled as the brand that sold them NOT the brand that made them, but the EIA always tells the true maker.

Zenith CRTs were probably industry worst in the 90's (EPA regs changing materials they could use threw them off their game), yet were basically industry best in the 70's (some of their 70's tubes have had almost continuous regular service then till now and still can muster a decent picture). The longer-lived brands are like wine: there are good years and bad years.

Has anybody given any thought as to how long the epoxy seal holding the faceplate to the funnel will last. Especially with the weight of the yoke and funnel pulling it down.

Magnavox/Philips 32" lasted over 100,000 hours on CRT, after 200,000 the second tube was OK but the chassis died (flyback), was not worth fixing since NAP had closed down and parts were not available. The replacement 48" flat screen in much better !!

You said it's a Magnavox - Philips tube?

I believe it is a Philips tube. Bonded yoke with no convergence rings.

Depends on the vintage. IIRC the bad admiral tubes were mid 60's to early 70's...Also check the EIA code. Many tubes were labeled as the brand that sold them NOT the brand that made them, but the EIA always tells the true maker.

Zenith CRTs were probably industry worst in the 90's (EPA regs changing materials they could use threw them off their game), yet were basically industry best in the 70's (some of their 70's tubes have had almost continuous regular service then till now and still can muster a decent picture). The longer-lived brands are like wine: there are good years and bad years.

Know where the EIA code would be located? it was a replacement I got from a guy named Jack where I used to live, back in 2004 or so.

Wow thats a shame. My zenith has an admiral tube in it.
I really doubt it came from the factory with an Admiral CRT, unless someone pulled the CRT from a scrap set.
IIRC, Admiral sold replacement CRT's of the common types.
I did see some Zenith's come through with RCA CRT's.

Know where the EIA code would be located? it was a replacement I got from a guy named Jack where I used to live, back in 2004 or so.

Is there a manufacturer's label? It should be on there as "EIAxxx"

Has anybody given any thought as to how long the epoxy seal holding the faceplate to the funnel will last. Especially with the weight of the yoke and funnel pulling it down.

That is not epoxy, but rather Frit glass. Frit glass is a special type of glass with a lower melting point that allows joining the face to the funnel without softening/melting the face/funnel glass, burning the phosphor or heating the shadowmask to the point of warpage. Should last indefinitely...It has been in use since the 50's and does not really fail on those tubes.

Know where the EIA code would be located? it was a replacement I got from a guy named Jack where I used to live, back in 2004 or so.
It is usually on the main sticker that has the CRT type number and most of the other info. Sometimes they put EIA in front of it so you know what it is, but often it is just a string of 3 or 4 numeric digits placed somewhere such that if you did not know about EIA numbers you'd guess it was some random meaningless number.

Google 'EIA numbers' or 'EIA (+ number on your tube)' to find the maker the number crosses to.

Well if there was any sticker that contained an EIN number its long long gone.

Only thing I see is a silkscreen printed ADMIRAL CODE H03 on the CRT bell and thats it.

Magnavox/Philips 32" lasted over 100,000 hours on CRT, after 200,000 the second tube was OK but the chassis died (flyback), was not worth fixing since NAP had closed down and parts were not available. The replacement 48" flat screen in much better !!

I must be misunderstanding something here.

So you had 100,000 hours on the original CRT, and 200,000 on the replacement for 300,000+ total hours? 300000 divided by 24 hours in a day divided by 365 days in a year would come to more than 34 years if the set was never turned off. They didn't make 32-inch TVs back in 1984, did they?

What year was your TV built, and how many hours a day was it used?

.

We got between 4 and 5 years out of a tube. And that was in 24/7 operation. Since there are 8760 hours in a year, I figure that about 35,000 hours or so.

Sounds like the Zenith jug got changed. Zenith always used Zenith
tubes ( EIA 343 ) or Rauland tubes (EIA 1101). Zenith owned Rauland
since the early 50's. IIRC the only exception was the first 14" color
that used an RCA ( EIA 274 ). In later years B&W tubes were mostly
Clintons. Small colors ( 9") also used an outside tube.

The NAP sounds like an RCA tube ( EIA 274). If its a NAP / Sylvania
EIA is 312.

TV life is based on the CRT. It was said a good set & jug should go
8 yrs. Average life must have gone to 20 yrs from the mid 70's
on with RCA , Zenith and some Sylvania tubes.

Last thing is the "bad" early 90's Zenith tubes. Zenith did extend the
normal 2 yr warranty on them. Up to 5 yrs on high end sets. The
tube would be free or at reduced price depending on age & price
of the set new. The dealer was also asked to pitch in with reduced labor.
No big deal, by then a CRT could be changed & set up in 15 mn.
The ones that got screwed were Sears customers. They bought most
electronics & self insured them. If your jug went in 2 yrs & 1 day
you got NOTHING from Sears or Zenith.

73 Zeno:smoke:
LFOD !

Sounds like the Zenith jug got changed. Zenith always used Zenith
tubes ( EIA 343 ) or Rauland tubes (EIA 1101). Zenith owned Rauland
since the early 50's. IIRC the only exception was the first 14" color
that used an RCA ( EIA 274 ). In later years B&W tubes were mostly
Clintons. Small colors ( 9") also used an outside tube.

73 Zeno:smoke:
LFOD !

Additional exception: Zenith's first consumer color TVs had IIRC RCA 21FJP22 CRTs in them...I've got one or two CRTs with the Zenith sticker but a non-Zenith/rauland EIA.

I know it was changed. I said in my post I replaced it with an Admiral I obtained. I just dont know what EIN it is.

Edit: Nope. I failed to mention that until a few posts down. Whoops.

We got between 4 and 5 years out of a tube. And that was in 24/7 operation. Since there are 8760 hours in a year, I figure that about 35,000 hours or so.

Nice. So I have basically doubled that on the CRT thats in my "nightly watcher"

It's good to have a baseline. I know that projection CRTs last far less time, I have had to retube an RPTV once.

Edit: My grandmother had one of the last RCA floor models, CTC203 I think it was. it never had any electrical faults, but back in 2013 or so the CRT got weak, as the picture is fuzzy with bad color bleed especially on reds and greens, the sun looks like its got flames on the right side.

How about those 16x9 color HD CRT's? I've got three of those sets.
Seems to me they might not last as long as a 3x4 regular CRT.

Also, consider some TV chassis designs drive a CRT very hard in the name of brightness and picture quality, Sylvania SuperSets being a major offender.
Considering that and the worst cabinet build quality I've ever seen, Mexican chassis assembly and an unobtanium 35 meg focus control, I eventually wrote mine off as a hopeless pile of junk. The only thing I liked about it is that it was a remote set with a motorized varactor tuner; fortunately I have plans for that and the attached remote system chassis.

My oldest sets (1982 and 1986) seem to be just fine, and I used the 1986 set all the time as a kid (the 1982 set wasn't originally mine). I wouldn't be surprised if they eventually had cap issues though.

Wow, I have in the basement a Magnavox 25" and a 19" Admiral in bedroom. Probably the Magnavox from 1993 and Admiral from late 90's. Still working well.