For one, that set uses selenium rectifiers. That chassis was their budget set.
Yes, RCA sets started having DC restoration, but, they just got cheap on construction.
Not saying it's not worth fixing. It probably is. But, the later, the more trouble they are.
Bill Cahill

Well it can't be any worse than my KCS 103, relatively speaking. :)

The RCAs from the kcs28 started using DC ideo amplifier coupling. This means that the DC component remains and a separate DC restorer is not necessary. The result is a better amplifier frequency-phase response and the pictures on these sets are amazing.

From the kcs45, the design went back to the DC restorer. The design was cheapened: the peak sync AGC amplifier disappeared and the AGC became cheap with simply a rectifier. Less sync amplification and the sync take off was after the contrast control to make up for the lost gain. Lastly, a high impedance horizontal deflection coil to match the horizontal output tube was introduced which was bad news.

From the kcs66 was an improved design. I like especially the return to DC video coupling and the introduction of keyed AGC to reduce airplane flutter.

From the kcs66, RCA had a wider range of sets from the very good to the pretty bad. The kcs 28 to the kcs 42 were all good.

Terry

[QUOTE=Adam;3014076]I like Zenith b/w sets from the late 50s through the early 70s (the years they used the horizontally mounted steel chassis, I think 59-74?) I've been using many of those as daily watchers for years, and find them to give me the least trouble of any sets I've owned. I currently have 9 of them. My '66 19" Zenith remote-controlled steel cabinet set is currently my main bedroom set.
I think this is the truest statement of any, included on this thread. These sets were state of the art at the time. Many had frame grid IF tubes and the almost indestructable gold video-guard tuner.

The early Zeniths were too overbuilt, leading to lots of headaches. By the mid-50s or so they really had their act together, though. I have noticed a lot of very weak crts in pre-60s Zeniths.

I've had good luck with the split-chassis, which is basically like recapping 2 radios. Their later one-piece chassis seemed straightforward, as did most of the mid-50s RCA sets I've looked at.

<chuckle> I have four of them, three still power up and function to some degree. They all need cosmetic help.:D

Seems like plain old parts count should have some bearing on reliability. My 1946 RCA 630TS has 30 tubes. My 1958 Philco Miss America has 18 tubes. I don't know offhand which is better engineered, but the 630TS has more potential failure points.

Phil Nelson

The 52 models had the selenium rectifier, heater transformer arrangement also. Some of the models had a 6BQ6 for a vertical output, which I found strange. All their models from 1952-54 had that power supply arrangement.

Just like GM, Chrysler and Ford had some really good cars but also had some really bad ones. TV manufactures had really good reliable sets and some not so good. And yes I doubt you will see a Predicta listed as a reliable set!

Personally any vintage set with phenolic circuit boards should not be considered reliable for the long haul.

What about the higher priced sets such as DuMont and Setchell-Carlson? Seems like those were built like tanks and meant to last forever! Some S-C consoles had the chassis above the crt and the top of the cabinet lifted like a car hood for servicing. I'd love to have one of those!

Im rather amazed by the simplicity of my 56 packard bell 24s, 18 tubes and only 26 caps. Its had three "oldschool replacement caps", but was working when i got it, it shows they must have been rather reliable. Its half as complex as my 1950 motorola.

Sorry everyone, im not up to your levels yet where i can talk knowledabley about them. Im still at the "stare at the schematics and replace one part at a time and pray for it to work" stage.

All of us wisely still use schematics, and, one part at a time. Nothing wrong in that.
As far as reliability, I'd like to find a good 1956 21" console deluxe RCA in good repairable shape. I really want one.
Bill Cahill

I have a couple of the early 1950s Hoffman Mark V sets. These seem to be very good sets with power transformers, 4 IFs, etc. The rectifier is a 5U4.

The also have true limiters on the sound systems, greatly reducing the annoying buzz (from the AM of the video leaking into the sound stages). That buzz is almost impossible to get out of some the later 1960s sets with the set running off of the strong signal from converter boxes, dvd players, etc.

As to which 1950s/1960s sets would possibly die the soonest, I have an answer to that also. I got some early 60s small GE portables from a TV shop that I cleaned out. GE mounted all the tubes on printed circuit boards(even the combination horizontal output/damper). A couple of these had not been used much, so I got them going again. The others had totally charcoaled boards.

Knock on wood, my split chassis Philco and my 54 Admiral are what I watch the most. They have been very reliable since I finally got them where I want them.

It always seemed if it could be built cheaper, GE would find a way. The later hybrid portables had a fiberglas based PC board that seemed fairly rugged.