How much time an '50's-early '60's color C.R.T. was expected to last (i'm talking especially about C.R.T's used at "R.C.A." CT-100... CTC-13...16 and "Zeniths"s)

Plenty were replaced, and I think that in a time when a typical family had one TV, excess usage took its toll. I repaired plenty of early & mid-60s color sets during the 80s & 90s, with original CRTs. So it's very feasible to say that a 21FJP22 could last 20 years with moderate normal use. I think that lots of CRTs were replaced unnecessarily back then. Easy job; big $. Typically it would bill out at around $200 to replace a 21" color tube in the 80s, and a rebuilt tube was $39.50 cost. Time to install & align was about 30 minutes.

Charles

I did a reasonable amount of servicing in the early 70's and getting the three electron guns to track and give good convergence was probably the cause of a lot of replacements. The "Mask" that the electron beams had to accurately shoot through, at the front of the tube was a big problem in those early days also.
The only products out that had any stability to them were Zeniths, with the big heavy power transformers and later in the 70's were the Sony Trinitron.
Broadcast monitors at that time had pix tubes costing $2000.

Fred

I think that the average life of a CRT tube is approximately 8000 hours

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I know we're talking about '50s and '60s vintage tubes here, but I'm amazed every day that the 27" Magnavox POS I bought as a store demo unit in 1985 and has been in constant use every day since then still shows a half decent picture.

--Dave

I think that the average life of a CRT tube is approximately 8000 hours

I think that's what you can expect out of most non-power handling tubes, about 10,000 hours. The currents from CRT cathodes are fairly low. Comparable if not lower than what a tube in the IF strip would see.

I think that lots of CRTs were replaced unnecessarily back then. Easy job; big $.

My favorite story about that is from around 1980 when I was working in the headquarters of a large corporation and one of our Sony monitors started misbehaving. We had that type of stuff serviced by a local TV repair guy. He took the set and brought it back a week later with a new Trinitron picture tube installed and a $300+ repair bill. Only problem was, the symptom was that the picture had collapsed into a horizontal line. Still, no one except me cared and he got away with it. I made sure we never used him again.

--Dave

Could tv shops sell your old tube as well? Or at least get it rebuilt and charge another customer for it when they replace another crt? I guess they could also say: "well, it will cost X to replace your old picture tube...of course, one of the tvs on our showroom floor could be had for just a few dollars more, which includes that fancy warranty..."

I heard of some tv shops installing used crts in sets . A friend of mine kept good used crts from junkers and installed them on customers sets when a crt was needed . However he specified that it was a used crt and didnt charge them for a new one . It usually saved the set and the customer wound up fixing it becuase they didnt have to spend X amount of dollars on a older set .

Could tv shops sell your old tube as well? Or at least get it rebuilt and charge another customer for it when they replace another crt? I guess they could also say: "well, it will cost X to replace your old picture tube...of course, one of the tvs on our showroom floor could be had for just a few dollars more, which includes that fancy warranty..."

It's illegal to sell used TV parts in California, according to the rules in the Bureau of Electronics & Appliance Repair standards. However, I've sold plenty of used parts & CRTs to people who were fully aware they were getting used parts, at a big savings.

Charles

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I think that's what you can expect out of most non-power handling tubes, about 10,000 hours. The currents from CRT cathodes are fairly low. Comparable if not lower than what a tube in the IF strip would see.


actually, it's the current density required to get a sharp spot that determines cathode life, not the total current per se.