Hazeltine developed the "Neutrodyne" TRF radio design and held a patent on the AGC circuit used in receivers. They also partnered with Leonard Kahn to develop the Kahn-Hazeltine AM Stereo system, which was invented in the late 1950s and was used by some stations the 1980s and early 1990s, until the FCC made the Motorola C-Quam system the single standard for AM Stereo in 1993.
I looked up Hazeltine Corp. and found they were primarily a defense contractor but did do some work in designing radio and TV circuits which they would patent and then license out to various TV and radio manufactures. They were also known for developing the Hazeltine computer terminal which was a crt and keyboard combined into one unit. When I was in High School in the early 80's we used Hazeltine branded terminals connected to a Digital Equipment Corp PDP system in my Data Processing class.
National was known as a very well built product that used a lot of government surplus parts from WWII. Those parts were well made to strict government specs.
I came across some engineering data while I was reviewing some information on vintage TV's and it was common for manufacturers to include two speakers, one emphasizing base tones and the other treble tones to provide tone control in the TV. The tone control itself was a potentiometer connected across the speakers thereby determining which tones would be shunted to ground. I found that interesting.
I suspect that was for sets from the 60s or 70s. The earliest set I know of with a woofer and tweeter is the GE Coaxial line from 1958-60 but those didn't have a tone control.
Bob, Fantastic series of videos you have. I have been watching them on the edge of my seat for a week now. Now this is real "Reality TV". One question, can you sometime talk about the differences in old picture tubes? You mention ion traps, straight gun vs. bent guns, aluminized vs. non etc... It would be great to hear a 10 min. rundown of the differences, history, of all of this. I have never looked into picture tubes in that much detail before but would be interested to know more. Keep up the good work! Herb Ithaca NY
Thanks. There are three basic B&W CRTs. Electrostatic, magnetic bent gun, and magnetic straight gun aluminized. There are a bunch of TV books from the 40s and 50s that cover them in detail. I don't really have the time to research the development history, dates and such,
The National Company was known for manufacturing communications equipment, and they manufactured many of their own parts. I think that they probably did manufacture this set, I have never seen anything manufactured by Hazeltine Research. Hazeltine's main business was developing circuits, patenting, and licensing those circuits, if they did manufacture anything it was much later on. I think that they held the Neutrodyne patents, an improved TRF radio circuit, and co-developed an AVC circuit with Philco.
21 tubes- quite a bit more than a 7- or 8-inch Motorola set, but then these weren't exactly cheap TVs. Apparently there was a version sold by National Toy Company called the Thrillbox.
Another collector just got one as well so I may dig into this set sooner than I expected so we can compare notes. antiqueradios.com/forums/viewtopic.php?f=3&t=242302
The information that I was reviewing came from "Elements of Radio" by Marcus and Horton and was published in May 1945. This is a college engineering textbook used to teach radio theory and its hottest chapter is on the then new CRT! It is possible that it may have found its way into your National TV.
They were probably just speculating about the sound systems that would be used since there weren't any commercial TVs until 1946. There is another version of this set in a metal cabinet with carrying handle It has a field strength meter in place of one speaker and was marketing as a way to find the best spot in a customers home to place their new TV.
It's currently in a climate controlled storage facility. My intent is to sell it when I find a complete set of matching knobs. Looking like that may never happen.
@@bandersentv I know nothing about electronics, but I found this video fascinating. Thanks for your reply. Couldn't the knobs be made with a 3D printer?
If I had one and I knew how make a 3-D model maybe, but they also have a metal insert. Also I haven't heard of anyone making realistic printed knobs. Molding seems to be the way to go.
i see ok when u opened it thats the first thing i saw see u can teach an old dog new tricks hey send me the round color tv dont see much on craigslist sarasota florida look it up have a good night from scott
Hazeltine developed the "Neutrodyne" TRF radio design and held a patent on the AGC circuit used in receivers. They also partnered with Leonard Kahn to develop the Kahn-Hazeltine AM Stereo system, which was invented in the late 1950s and was used by some stations the 1980s and early 1990s, until the FCC made the Motorola C-Quam system the single standard for AM Stereo in 1993.
Thanks for the info.
I looked up Hazeltine Corp. and found they were primarily a defense contractor but did do some work in designing radio and TV circuits which they would patent and then license out to various TV and radio manufactures. They were also known for developing the Hazeltine computer terminal which was a crt and keyboard combined into one unit. When I was in High School in the early 80's we used Hazeltine branded terminals connected to a Digital Equipment Corp PDP system in my Data Processing class.
Ah yes, I do remember Hazeltine terminals :)
I swear you always find the coolest televisions I have ever seen.
Hazeltine produced Magnavox TVs and radios among other electronic components; I remember we had a 24" B&W TV with great sound as well.
Hi Bob. I was hoping to see you restoring this set, It's very interesting how the did the high voltage. Thanks for sharing and take care.
National was known as a very well built product that used a lot of government surplus parts from WWII. Those parts were well made to strict government specs.
I came across some engineering data while I was reviewing some information on vintage TV's and it was common for manufacturers to include two speakers, one emphasizing base tones and the other treble tones to provide tone control in the TV. The tone control itself was a potentiometer connected across the speakers thereby determining which tones would be shunted to ground. I found that interesting.
I suspect that was for sets from the 60s or 70s. The earliest set I know of with a woofer and tweeter is the GE Coaxial line from 1958-60 but those didn't have a tone control.
When I was a kid, we had one that was about 5 feet tall. It had HUGE doorknob tubes that glowed PURPLE in back...
Bob, Fantastic series of videos you have. I have been watching them on the edge of my seat for a week now. Now this is real "Reality TV". One question, can you sometime talk about the differences in old picture tubes? You mention ion traps, straight gun vs. bent guns, aluminized vs. non etc... It would be great to hear a 10 min. rundown of the differences, history, of all of this. I have never looked into picture tubes in that much detail before but would be interested to know more.
Keep up the good work!
Herb
Ithaca NY
Thanks. There are three basic B&W CRTs. Electrostatic, magnetic bent gun, and magnetic straight gun aluminized. There are a bunch of TV books from the 40s and 50s that cover them in detail. I don't really have the time to research the development history, dates and such,
nice blue selenium rectifier..neat "doorknob" capacitors.I like those really waxy looking paper capacitors too
I plan on restuffing those wax caps :)
The National Company was known for manufacturing communications equipment, and they manufactured many of their own parts. I think that they probably did manufacture this set, I have never seen anything manufactured by Hazeltine Research. Hazeltine's main business was developing circuits, patenting, and licensing those circuits, if they did manufacture anything it was much later on. I think that they held the Neutrodyne patents, an improved TRF radio circuit, and co-developed an AVC circuit with Philco.
21 tubes- quite a bit more than a 7- or 8-inch Motorola set, but then these weren't exactly cheap TVs. Apparently there was a version sold by National Toy Company called the Thrillbox.
Can't wait to see this one on the bench!
Another collector just got one as well so I may dig into this set sooner than I expected so we can compare notes. antiqueradios.com/forums/viewtopic.php?f=3&t=242302
do you have any sets with tuning fork remotes?
No, but a friend has a GE coaxial set that uses an RF remote similar to a garage door opener. Someday I hope to restore it.
One of my Deforest Crosley radios says Hazeltine Corporation on it...National ham radios look very cool!
The rapid camera movements make me feel queasy.
Me too. Motion sickness!
cool looking chassis
Wonderful!
The information that I was reviewing came from "Elements of Radio" by Marcus and Horton and was published in May 1945. This is a college engineering textbook used to teach radio theory and its hottest chapter is on the then new CRT! It is possible that it may have found its way into your National TV.
They were probably just speculating about the sound systems that would be used since there weren't any commercial TVs until 1946.
There is another version of this set in a metal cabinet with carrying handle It has a field strength meter in place of one speaker and was marketing as a way to find the best spot in a customers home to place their new TV.
i think i spied a slight editing fail, at around 10 - 11 minutes
I don't see it ?
*****
OK, I see it now. I think it's so compelling you need to see it twice ;)
You sure do like those 7" sets lol I'm sure it will be a fun restoration to watch.
Much easier to collect than consoles ;)
I enjoyed watching this. What happened to this set?
It's currently in a climate controlled storage facility. My intent is to sell it when I find a complete set of matching knobs. Looking like that may never happen.
@@bandersentv I know nothing about electronics, but I found this video fascinating. Thanks for your reply. Couldn't the knobs be made with a 3D printer?
If I had one and I knew how make a 3-D model maybe, but they also have a metal insert. Also I haven't heard of anyone making realistic printed knobs. Molding seems to be the way to go.
Someone is selling a TV-7M right now on eBay for around $500...(but then this guy is very unreasonable on most of what he sells)
Yes 1
ok sir
A 1949 model !
Nunca prendiste la wea
the yoke is missing
I uses an electrostatic CRT so doesn't need a yoke.
i see ok when u opened it thats the first thing i saw see u can teach an old dog new tricks hey send me the round color tv dont see much on craigslist sarasota florida look it up have a good night from scott
Scott Gurne
Round color TV ? I don't have any of those. Too many other collectors in my area.
ok