Any one have info on this TV?

[Chad Hauris]

If you are not experienced with wood working it would be wise to first make some drawings of how you think it should go together, then build a rough model of the set to start out with so you can determine experimentally the best way to put everything together. I would not start out buying fancy stuff like with veneer because it may get messed up if you find that what you thought might work-- doesn't. This is not an easy product to start out with in cabinet making.

Keep in mind that this set is not really a cylinder, it is more like a portion of a cone that is inverted.

[jshorva65]

Since the mounting of the Admiral 19A1X chassis chosen for the set is via four screws through the chassis bottom, a vertically-mounted, removable "shelf" would be necessary. The chassis would be bolted to the shelf and then the shelf would bolt inside the cylinder such that the front panel control shafts would extend through holes in the tabletop. Adjustments for brightness, focus, horizontal and vertical hold would need to be considered preset "service" controls unless some means were provided via dial-cord type linkages to facilitate the operation of these rear-apron controls by means of front-panel knobs. Otherwise, there would be no access other than through the back or bottom of the cabinet for making such adjustments. Raster Size, Linearity and Centering could easily remain as "service" controls. In fact, the Vert. Lin. control was a bit of an "afterthought" on the 19A1X series. None is shown in the original Sams literature. A subsequent "Production Change Bulletin" (part of Set #106 IIRC) shows this control added to the circuit.

Originally posted by jshorva65
Regarding the proposed tube complement for a 9kV RF supply, a pre-war tube complement such as 6N7 (or 6SN7), 6L6G, and 8016 (early Industrial precursor of 1B3) could be used. I believe American engineers may have developed RF oscillator supplies pre-war and either developed the flyback method as part of radar development during the war, or learned the technique from others. . .

Philo Farnsworth developed the flyback HV supply in the early 1930s and was issued a patent for it in 1936.

(Farnsworth patent #2,059,219 "Generation of the High Voltage from the Horizontal Scan Frequency" issued Nov. 3 1936).

Farnsworth may have been the first to apply a flyback for use in televisions, but a very strong argument can be made that Tesla actually invented the basic device.

His air core coil is essentially a flyback, and even the Kettering point ignition system owes much to the Tesla coil.

Anthony (don't get me started on Tesla! LOL)

[jshorva65]

Philo Farnsworth developed the flyback HV supply in the early 1930s and was issued a patent for it in 1936.

Thank you for locating the specifics on the flyback supply. As I suspected, it was an American inventor who developed the system upon which circuit designs for television HV supplies are still based today. The fact that the 6L6-driven flyback HV supply of the Farnsworth (listed in the Sams index as Capehart) 610P, 651P & 661P was obviously a part of the original prewar schematic makes perfect sense given this information. The set's postwar modifications which were incorporated prior to its reaching the market in 1948 included a 13-channel tuner (suspiciously similar in its circuitry to that of RCA 630TS), replacement of the original AM sound channel with an FM circuit, horizontal AFC circuitry which was located on a separate chassis, and the aluminized-screen 10FP4 picture tube. Anyone who has access to Sams Set #95A will find the schematic for this model included in that packet. The almost-exclusive use of prewar octal tubes with the exceptions of the few miniature tubes in the tuner, video det, video amp, audio IF and horiz. AFC strongly suggest that set was a prewar prototype with some postwar modifications. It is also noteworthy that one of its two 8016 HV Rect. tubes appears to act as half of a doubler while also performing damping action in the output plate circuit. Although I am not certain of that, it does appear upon looking at the schematic that this is the case. I have not actually worked on this chassis and thus have not had the opportunity to analyze waveforms to confirm my suspicions. I suspect, however, that if a scope, a 100:1 HV probe and a 661P chassis were set up for analysis there would be some clipping of the plate pulse through the action of the 8016 diode which would tend to damp high-frequency oscillations during retrace, producing the smooth sawtooth current required for proper sweep. Having only an EE Tech degree, as opposed to a full EE degree, I can only speculate. Math studies for my degree ended with basic Calculus, so I lack in-depth understanding of Laplace (sp), Fourier (sp), or Differential Equations. Basically, I was trained to be an assistant to engineers.

[jshorva65]

Farnsworth may have been the first to apply a flyback for use in televisions, but a very strong argument can be made that Tesla actually invented the basic device.

IIRC, Tesla was one of the many Christians forced to flee prior to the coming of the atheist Bolshevik death squads in Russia, which is what brought him to America in the first place.

Don't get me started on the 65 million Christians murdered over there between 1917-1945 and how my great-grandparents were among those few who managed to escape with their lives before the Iron Curtain would have trapped them. I owe my very existence to the fact that the 1905 Bolshevik Invasion and some rarely-mentioned earlier attempts to implement Marxism failed. I hold a special contempt for the likes of Trotsky, Lenin, Stalin et al and for the modern-day American neo-Bolshevik elements who are currently de-industrializing my beloved America while nullifying the Bill of Rights and establishing atheism as the official religion here in direct violation of the Establishment Clause of the First Amendment after their success in violating the Free Exercise Clause with the banning of prayer in schools some time ago. Stand up for your country, punch a traitor ... lol

Originally posted by jshorva65
. . . The fact that the 6L6-driven flyback HV supply of the Farnsworth (listed in the Sams index as Capehart) 610P, 651P & 661P was obviously a part of the original prewar schematic makes perfect sense given this information. The set's postwar modifications which were incorporated prior to its reaching the market in 1948 included a 13-channel tuner . . . .
The almost-exclusive use of prewar octal tubes with the exceptions of the few miniature tubes in the tuner, video det, video amp, audio IF and horiz. AFC strongly suggest that set was a prewar prototype with some postwar modifications.

The weak point in the pre-war designs was the available tubes for VHF use. These included the 1852 and 1853 octal metal RF types used for RF amp, mixer, and IF amp. These types will not work above 100 MHz, and are the main reason why pre-war tuners were low band only.

There is an interesting article in RCA Review (1946 I think) about wartime tube development. New VHF types were needed immediately for radar, and the first design was the 6C4 in 1942, followed by the 6J6 in '43, quickly followed by the 6AG5, 6AU6, and 6AL5.

When the war ended, RCA and others had millions of these new types in surplus, and they were just what was needed to upgrade the pre-war TV designs. In 1946 the RCA 630 used (3) 6J6s in a new tuner design that added the high band channels, and 6AG5s and 6AU6s in the IFs. The 807 was given an octal base and became the 6BG6G, but the 5V4 damper used in 1939 remained. Even though all TV manufacturing halted during the war, TV design did not. The upgrades were added to the designs during the war as the new miniature tube types became available, in preparation for post-war manufacturing.

[Steve McVoy]

The only prewar set that we know of that used a flyback HV supply was the German E1: http://www.earlytelevision.org/e1.html

Farnsworth may have patented the flyback supply, but there is no evidence that he used it prior to 1948.

Farnsworth had TV prototypes before the war, but didn't manufacture any TV receivers until 1948. Before the war, the Farnsworth company made radios and radio-phono consoles. Some had the Farnsworth name, and some had the Capehart name (Farnsworth and Capehart merged in 1938).

[prewtv]

Top is started. Did not make as thick as orig?
It is 1.5 inches thick.
Plywood tube is here, they came in 27.5 length, might be too long?
Conga drum for CRT housing should be done next week.
Large wood bowl be here next week?
Have site with PICs also
http://home.earthlink.net/~dchoinski/

You could name that set a Ricky or Baba Lou!

Anthony

[prewtv]

Conga drum wood done looks good??
still needs bezels, Crt, and post to hold it up.

http://home.earthlink.net/~dchoinski/

[prewtv]

If I use these chassis, easy to put all controls up?

http://home.earthlink.net/~dchoinski/

[peverett]

This project reminds me of a TV that I saw at the last Houston Vintage Radio Association auction. Someone had taken a Motorola VT-71 type TV and built a "Cathedral TV" out of it. It looked pretty authentic from a distance, but you could tell it was hand made up close.

The set went for over $400, so someone liked it.

[prewtv]

Originally posted by peverett
This project reminds me of a TV that I saw at the last Houston Vintage Radio Association auction. Someone had taken a Motorola VT-71 type TV and built a "Cathedral TV" out of it. It looked pretty authentic from a distance, but you could tell it was hand made up close.

The set went for over $400, so someone liked it.

You might be correct. I wanted to build it for under $1000.00
and my work cant be as perfect as the experts in each field, wood, metal, ect, and I used premade items where possible, conga drum for CRT, premade plywood tube for table.
Will try to take update PICs on weekend, TV has legs on and metal bezels and surports are done but not final painted, only major item left is wood slats at speaker and for that I have no clue yet on how to do them.