Early tv techs faced color challenge

[Adam]

Was there really that much tube failure in the old days? I find most old sets don't really need many new tubes, when I repaired my 721TS, I mainly just replaced capacitors, a few wires with the insulation comming off, 3 toasted resistors, and only one tube, the 6K6 audio output, and it even worked ok with the super weak one that was in there. And I've been watching my little 1956 8" RCA in bed every night for a while now and many of the tubes in that set are original. I will say that color sets always seem to need more tubes replaced, particularly tubes in the color circuits are often bad - those 6GH8s are usually bad among others.

[Chad Hauris]

I do think that when the sets were "younger", tube related problems were the most common, as other components had not aged enough.
Usually the biggest problem today is age-related problems like bad capacitors, bad wiring, etc. and tube related problems are fewer as the sets have been idle many years and have not been using the tubes.
TV sets seem to be often designed right to the edge of tube capabilities and when the sets are run for 10 or 12 hours at a time every day, some tube failures seem to happen after about a year or so of this kind of use.

[El Predicta]

I remember reading somewhere that more tubes were sold in 1957 than any other year. Interesting in that solid state was at least another 1o or so years down the road. Also remember reading that the average consumer back then averaged slightly more than 2 service calls per year on tvs.

[peverett]

I wonder if the peak in tube sales was due to the radios beginning to transition to solid state. The sales of 50C5s and 35W4s(the most commont tubes to fail in table radios of the time) would have began declining.

[3Guncolor]

KIeep in mind we run our tube equipment very little today. So as Chad said age related problems are what we face. We changed a lot of Horiz outputs etc as I remember in the 70's. Even the Zeniths needed about one service call a year if it was used hard.

[oldtvman]

Originally Posted by Chad Hauris

I do think that when the sets were "younger", tube related problems were the most common, as other components had not aged enough.
Usually the biggest problem today is age-related problems like bad capacitors, bad wiring, etc. and tube related problems are fewer as the sets have been idle many years and have not been using the tubes.
TV sets seem to be often designed right to the edge of tube capabilities and when the sets are run for 10 or 12 hours at a time every day, some tube failures seem to happen after about a year or so of this kind of use.

But conversely today's components don't fail as much as the solder connections that hold them together. Back in the day it was pretty unusual to find cold solder connections, today it's not that uncommon at all.

I do agree that back then most of the problems were 1st echolon problems such as tubes, crts, dirty tuners and controls. I don't expect that the designers had a clue some of these guys would be alive and kicking today.

[oldtvman]

Originally Posted by peverett

I wonder if the peak in tube sales was due to the radios beginning to transition to solid state. The sales of 50C5s and 35W4s(the most commont tubes to fail in table radios of the time) would have began declining.

I worked at an Rca parts distributor as service manager. The most popular tube was the 6gh8, followed by the horz out and damper tubes and of course the 3a3 and 6bk4

[peverett]

Oldtvman, in the TV repair field your list is exactly what I would expect. Although I worked in a TV shop for a very limited time in the 1970s, this is exactly what I remember.

I was just speculating that since radios were becoming solid state, the sale of the few 50C5s and 35W4s used in radios would be decreasing. I thought that this might explain why 1957 was the peak year of tube sales.

A couple of other things going on were:
1. Car radios were transitioning from tube to solid state. I had a 1960 Falcon-it had 12 volt tubes and 1 transistor. I also had (and have) a 1963 Falcon, it has a solid state radio. (My grandfather's 1953 Ford was all tube with a-almost always non-functioning-vibrator).
2. The low voltage rectifier tubes, 5U4s, etc were being replaced by diodes. The same is true with some of other diode type tubes such as the dual diode used in some TVs horizontal sections. (However, I would expect the increase in tube count due to color sets would more than offset this).

[peverett]

A couple more items were also changing in the late 1950s.

1. There were more multi-function tubes being developed such as the compactron and many 9 pin dual section tubes. Where a TV previously had a seperate tube for the sync seperator and video amp, one now might be used.
2. Higher gain tubes were being introduced. Where a TV might of had 3 IF stages (some had four), in the middle 1950s, by the mid 1960s, many B&W sets had only two IF stages.

I suspect that these also contributed somewhat to declining tube sales (in raw numbers) in the 1960s.

[dtuomi]

Originally Posted by Chad Hauris

I do think that when the sets were "younger", tube related problems were the most common, as other components had not aged enough.
Usually the biggest problem today is age-related problems like bad capacitors, bad wiring, etc. and tube related problems are fewer as the sets have been idle many years and have not been using the tubes.
TV sets seem to be often designed right to the edge of tube capabilities and when the sets are run for 10 or 12 hours at a time every day, some tube failures seem to happen after about a year or so of this kind of use.

I'm not sure. I think its probably dependent on a lot of factors. My experience is that its always a bad cap, almost never the tube. In fact bad caps blow tubes. Rarely the other way around.

I've got a little Portacolor on my desk at work that I bought from Adam over a year ago. Its sat there running everyday for 14-16 hours a day and still operates the same as when I got it. I use it to monitor the station I work for. But, other than snickering from some fellow employees I have had no problems with it. So I guess millage will vary.

David



-And no, I don't work for KTLA, I made that picture from a broadcast commemorating a local news anchor passing away.

[peverett]

It has been my experience that component construction, especially capacitors, improved greatly after around 1960. The "orange drop" type capacitors, etc began to appear.

This is probably one reason that the little Portacolor keeps on going. I also have one, a 1977 model, the works fine after clearing up a carbon trail in one of the adjustent conrols.

(GE was kind of strange when it came to CRT construction-I have seen some of the CRTs, from the Portacolor and some B&W sets with huge cathodes-these tubes seem to last forever. I have seen other B&W crts from them with little tiny cathodes-these are almost always very weak).

[Adam]

It's good to see that portacolor is still working, I bought that in a thrift store in MI a few years ago, and I don't think I ever even had the back off, it probably still has original caps, tubes and everything.

[andy]

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[oldtvman]

Originally Posted by Adam

It's good to see that portacolor is still working, I bought that in a thrift store in MI a few years ago, and I don't think I ever even had the back off, it probably still has original caps, tubes and everything.

I still have one of the first porta-color sets up in the attic from 1965, I remember I paid $249.95 for the set. Those old Ge sets would run forever.

[radiotvnut]

I used to see a lot of PortaColor's and most of them were easy to fix. I should have kept one of the late '76 models I once had since that was the last American tube TV. I think the best Solid State GE chassis was the PC chassis of the '80's. I used to drag a bunch of those home and mostly what was wrong with them was a 100 uf cap in the vertical circuit or bad power supply caps.