CANADIAN MARCONI - HOME ENTERTAINMENT
Featured here are various vacuum tube home entertainment radios starting from the 1920's. Your webmaster * does not * have any manuals or schematics for any of the devices featured in this section. Manuals and schematics for many Canadian Marconi radios are available free from the Pacific TV web site. Schematics not found at either of the above sites can be purchased from Antique Radio Schematics for a nominal charge, Just Radios is another site providing Canadian Marconi schematics for a small fee. .
In addition, more schematics and technical information about Canadian Marconi radios can be found at this summary listing at the Radiomuseum.org web site.
A photo montage of Marconi entertainment receivers can be found at the Radio Attic Archives web site.
This extrsact from “The Early Development of Radio in Canada 1901-1930 by Robert Murray” is likley in the context of the mid 1920s era.
"Production of broadcast receivers, which at that time tended to be produced only from about the beginning of July until around Christmas time. Then there was a complete lull and absolute cessation of production from about the beginning of the year through until early Summer. This period, although an idle one from the factory point of view was a very busy one from the design point of view. It was during the early months of the year that the sales people provided the design engineers and the factory with their ideas as to what the market would require and then there were the usual processes of technical design, the preparation of drawings, the preparation of models, certain kinds of field testing and finally an authorization for production. In those days, the quantities manufactured were relatively small and as I recall our output was limited to 50 or 100 sets a day at the peak”. (Unpublished recollections of S.M. Finlayson, CMC President from 1951 to 1964).
|This is the cover page only of the 1927-1928 Marconi radio catalogue. Click on image to enlarge. The rest of it is not available at this time. (E-bay image)|
RADIOS - LISTED BY MODEL NUMBER
Arabic and Roman numeral model designators are sometimes used interchangeably when refereicing the earliest of Canadian Marconi radios.
|As one goes back in time, information on the oldest Marconi receivers becomes scarcer. A chart showing the production of Marconi receivers (1921-1931) was prepared by Roger Hart and published in the 1999 Vol 7 edition of the Ottawa Vintage Radio Club Newsletter.. For model 26C, the tube count is in error. It should probably read as 7 instead of 27.|
|22||23||24||26||27SW||28 (Echophome 40)||29|
|31 31SW||32||32B||33||34||35 36 37 38||No model 39|
|Echophone 40||Marconi 40||41 41AW||No model 42||43 45||44|
|46 47||48||49 51||Echophone 50 60||53||54||55|
|57||58 59||60 61 60A 61A||62 62AC 63||64 65||66 67 68||69|
|70||71 72||73 74 75||76 77||78||79||80|
|81 82 83||84||85||86 87||88 88A||89 89A||93 94|
|95||96 97||98||99||100 101|
|102||103||104||105 105A||106 107|
|108 109||110||112||113 114||115 121||116||117|
|126 127||128 129||128A 129A||130 131||132 133||134 135||136 137|
|145||146||147 148||149 150||151||152||153 154|
|155||156||157 158||159 160||161||162||163 164|
|165||166||167 168||169 170||171||No models from 172 to 179|
|180 180A||181 181A||182||183 183A||184 184A||185 186||187 188|
|188A||No model 189||190||191||No model 192||193 194||No model 195|
|196 197||198 199||200A 200B||200C 200D||200 200E||201 201A 201B||202 203|
|No model 204/205|
|216||218||219||221 223||222||227 /227A|
|228 229||230||231 231A||233|
|235||236||238 243||252 253FM||258||261|
|271 Series||274 Series||275 275A||276FM||277FM Series|
|301 331||302 303||305||306||317|
The models listed below were made by Canadian Marconi but photos are not available at the present time. Schematics for these sets can be found at the web sites listed at the top of this document. Besides home radios, car radios, record players and wire recorders are included . The Marconi Service Manual is a hard cover service manual covering early Marconi radio models (Prior to WW2). Model numbers up to 215 (also models 291 and 294) are included in this manual.
Many of these radios were made in both tabletop and console models hence they would share the same chassis and schematic. If the model is featured in the above table, it will not appear in the list below.
A few Echophone radios are shown in the Table Of Contents in the Canadian Marconi service manual Volume 1 as being made by the Echophone Radio Company of Canada . Per the book "Radios in Canada by Lloyd Swackhammer" , Echophone made radios for the Canadian Marconi Company in Montreal. Specifically, these were the models 40, 50, and 60 . Things can become confusing since the Echophone 40 and 60 models overlap with Canadian Marconi models 40 and 60. Echophone model 50 has no overlap. with Marconi. Echophone was eventually bought out by the Hallicrafters company.
217, 217A &B, 217SW, 219 & 220, 224, 231, 238 & 243, 254-FM & 255-FM, 258, 260, 267, 279, 280, 284
303, 305A, 307, 310, 315, 327, 331, 332, 334, 339, 341, 355, 362, 369, 379 & 389, 342, 349, 359, 361, 365 & 367, 368, 369 & 370, 376 & 399, 385, 388.
403, 407,, 409, 415, 422, 423, 424, 425, 425A, 428, 431, 436, 440, 441, 442, 447, 449 & 624, 452, 455, 462, 464, 465, 466, 467, 468, 469 & 470, 476, & 477, 480, 481, 482, 483, 484, 485,& 486, 488, 495, 490,491 & 495, 499.
516 to 530, 588, 6A10, 6B10, 6B30, 6B42, 6B45, 6MF080, 6MN-082
1003, 1005, 1006, 1007, 1008, 1009, 1008A, 1009, 1070, 1071, 1072.
In keeping with the theme of this web site, here is a sampling of televisions built by the Canadian Marconi company. Any photo contributions of Canadian Marconi TVs would be most appreciated. Contact: firstname.lastname@example.org In this research it was discovered that dates given, might be marketing versus production dates. The dates shown in all the TV documents are assumed to be production dates.Masterpiece
169K23 191K23 192K23 194W23 (1950s)
303K21 332K23 (1950s) 333K23 Citation
Custom Series (21")
Deluxe Series (21")
(1950 and 1951)
(1950 and 1951)
The primary purpose of this research is to document some early history on how television evolved in Canada and also some advancements in TV technology over the decades. In this narrative, the term "early television" can be referencing the first mechanical TVs or the growth of television after WWII, depending on the context. Some of what is written here was actually experienced by the author over the decades.
The invention of the television was the work of many people in the 19th century and early 20th century. Television stations were operational in the US before any Canadian stations went on the air. The first regularly scheduled TV programming began in the United States on May 11, 1928. General Electric programs were transmitted from station W2XB in Schenectady, New York using a 24 line mechanical scanning system. It would be safe to assume that any television station from this era would be using a mechanical scanning system since standards had not yet evolved.
In Canada, the first television station, VE9EC, was an experimental one based in Montreal, Quebec. It broadcast between October 9, 1931 and 1935, showing neon red and black pictures. The station was owned by La Presse and radio station CKAC. VE9EC used a mechanical scanninmg system which broadcast 60 to 150 lines of resolution on a frequency of 41 MHz. Broadcasts were witnessed by over 100,000 people who lined up to view images at the Ogilvie Department Store on Ste. Catherine Street in Montreal. Over time, new electronic scanning systems were able to deliver more scan lines thus improving resolution tremendously.
The 1940s and 50s were a critical period for television development with the adoption of the first broadcasting standard. The 525 line National Television System Committee (NTSC) standard was developed in 1941 but it had no provision for color nor would it enter volume production until after WWII ended. In 1953 a second NTSC standard was adopted, which allowed for color television broadcasting and was compatible with the existing population of black-and-white receivers. NTSC was the first widely adopted broadcast system and remained dominant until 1997, when it started to be replaced with different digital standards such as the Advanced Television Systems Committee (ATSC) and others.
By the late 1940's, Canadians who lived in close proximity to US border cites could watch American shows and programming where available. In order to promote the sale of TV receivers, the transmitters and the programming had to be there first and not the other way around. Merchants who sold televisions in Canada had to import them from the US since there was no TV manufacturing in Canada around this time.
The first television manufactured in Canada was in 1948 at Canadian Westinghouse in Hamilton Ontario according to Wikipedia. However, on the Time Line at the Moses Znaimer TV site, Canadian General Electric is shown as the first major company to manufacture TVs for Canadian consumers in 1948. For now, this is flagged as a conflict of information.
In the September 1949 issue of the American Radio-Phono-TV Marketing periodical, it was announced that Canadian Fairbanks Morse and Canadian Marconi would start to build radios and TVs for Emerson Electric for sale in the Canadian marketplace. It was to be on a royalty basis as evidenced in a separate announcement. This was the beginning of TV manufacturing for Canadian Marconi. The company also built the model TV100 which bears an identical appearance to the American General Electric model 10T5 of 1949. The CMC History copy posted to the Esterline web page indicates that by 1951, televisions were designed and manufactured in-house. Up to that point it is presumed that Marconi was only making televisions using other company's designs.
|This is the copy which announced Marconi's entry into TV manufacturing. (Courtesy Google Books)|
Another early Canadian television set was the Viking Console, appearing in 1952. The stylish set was sold by the Eaton’s department store chain and manufactured by Electrohome in Kitchener, Ontario . Viking was the Eaton's house brand. There was also the Rogers-Majestic brand of television produced by Phillips Electronics Canada. RCA opened a television production plant in Prescott, Ontario in 1953. The television set production and acceptance by these well established Canadian businesses was a great boon to the Canadian television industry. In 1951, there were in excess of 90,000 sets in Canada, and by 1953 this increased to over 300,000.
On September 8, 1952, CBC Television made its historic debut in Montreal as station CBFT. However, Canadians with TVs had already been tuning into American border TV stations since the late 1940s. The CBC had set a target of September 1951 for the Canadian debut of television but equipment shortages caused by the Korean War pushed the date back to 1952. It is believed that Canadian Marconi started their own TV designs in 1951, however this date is subject to verification.
By 1966, Canadian Marconi company was deemed to be in conflict of interest due to the fact that it owned both a broadcasting station (CFCF) and also manufactured domestic television sets and radios. Consequently, the company sold its broadcasting interests and ceased the manufacturing of domestic TVs and radios.
ADVANCEMENTS IN TECHNOLOGY OVER THE DECADES
Television design and technology changed immensely over the decades. These changes can be categorized into the groups shown below. These are arranged alphabetically and not chronologically.
Many TVs that were present in urban areas and where a local station was available, used rabbit ear antennas to receive signals. These rabbit ears consisted of two telescoping arms arranged as a Vee. For optimum reception, the arms would be lengthened for the low VHF channels (2 to 6) and shortened for the high VHF channels (7 to 13). Sometimes the rabbit ears would have to be rotated for maximum signal reception. Ghosting was also a problem in those days. First, the primary signal from the transmitter would received. If any of the signal was reflected from say a tall building or even an aircraft in flight, the reflected signal would arrive a moment later and had the effect of casting ghosts on whatever was being received. Some folks even made their own indoor antennas using tinfoil.
As the distance from the transmitter to the receiver increased, rabbit ears could no longer do the job. Cable TV had not yet arrived.
Homeowners had no choice but to erect outdoor antennas. These were affixed to a tubular mast and supported with guy wires attached to the base of the roof. The outdoor antenna could assume several configurations. In Hamilton Ontario, two antennas were required to receive Canadian and US programming. One antenna would consist of a low VHF Yagi which was pointed to Buffalo NY in order to receive Channels 2 (NBC), Channel 4 (CBS) and Channel 7 (ABC) . A high VHF folded dipole with a reflector element was pointed towards Toronto to receive Channel 6 (CBC) and Channel 9 (CTV) Both antennas were connected to the TV set with 300 ohm twin lead and terminated on a ceramic, double pole, double throw knife switch which was affixed to the back of the TV. The two poles of the switch would be connected to the antenna terminals of the TV. This arrangement meant that the viewer had to change the position of the switch depending if a low or high VHF channel was too be received. This was the typical antenna configuration for Hamilton and surrounding vicinity.
For viewers who didn't want to fuss with flipping a knife switch when changing from low to high VHF channels, they could erect an all purpose VHF/UHF antenna on a rotor. This had one slight disadvantage. If the desired station was 180 degrees away from the current position, the viewer would dial in the new position , then wait for the very slow rotor to swing the antenna to the new position.. At installation time, the rotor control would have to be "calibrated" by first receiving all stations within the antennas range, then marking the face of the rotor control box with the station numbers. Rotors could also be prone to icing during winter conditions. Back in the 1950s and 60s it was real easy to tell which houses had a TV and which ones didn't.
In September 1952, small scale cable TV was being evaluated in Toronto and Montreal. Eventually, these early tests would create a whole new industry. As cable subscriptions grew, rooftop antennas started disappearing one by one. There are now a multitude of ways to receive television content, with fiber cable and satellite reception dominating the landscape. A segment of the population have opted to "cut the cable" and receive their programming via high-definition, purpose-built VHF/UHF (47 to 862 MHz is an example) combination antennas, supplemented by the Internet's streaming content sources such as Netflix or CNBC. There is still a viable market for satellite dishes in rural areas where the stations are out of range and the dwellings are spaced too far apart for the affordable installation and operation of cable TV.
Early television cabinets could be very ornate and were available in many types. Walnut and mahogany were two popular woods used in the fabrication of cabinets. Some sets could be purchased in a particular furniture style such as French Provincial. Some TVs came with a built-in radio and phonograph. But what was one to do if the television wore out before the radio and the phonograph?
Cabinet styles could be as simple as a cube shaped box sitting on peg legs or elaborate floor consoles. Black plastic has now displaced wood as the cabinet material.
CATHODE RAY TUBES
CRT sizes grew from 5 inches in the late 1940s all the way up to 43 inches in the 1990s.
As the CRT size grew, it became imperative to protect the CRT from inadvertent damage by the user. To prevent an accidental implosion of the CRT, a tinted safety glass, akin to that of an automotive windshield, was placed in front the CRT. Later on, the safety glass became an integral part of the CRT thus eliminating the need for the occasional cleaning of the standalone safety glass. This also helped to reduce the cost of the television. It was your webmaster's personal experience to have witnessed the sudden crazing of the entire safety glass on the family's television. When it happened it sounded like a gun shot. This may have been caused by the cabinet applying stresses on the safety glass but it was sure nice to know that it stayed in one piece. CRTs frequently became gassy and had to be replaced. Depending on usage, one could get at least 10 years of life from the CRT. Eventually, CRT makers made the tubes last longer.
Near the end of the CRT era, Sony offered flat screen CRTs in their Vega series of televisions but this was probably too little too late.
Just around the corner was the debut of the high resolution flat screen TV which made the CRT and projection televisions completely obsolete. Flat screens can display 720 lines (Standard Def) or 1080 lines (High Def) and the largest models can be fabricated up to 108 inches diagonal . For a while, 3D television looked promising but it too will be discontinued in 2017 due to low consumer demand. The latest standard is called 4K (aka Ultra High Def) . A 4K TV is capable of displaying 2160 lines in progressive scanning mode. When the transition from CRT to flat screen occurred, the aspect ratio also changed from 4:3 for a CRT to 16:9 for flat screen TVs .
CIRCUIT DESIGN AND VACUUM TUBES
Early televisions used an intermediate frequency (IF) of 21.25 MHz for the sound and 25.75 MHz for the video. This design was problematic if the viewer lived in the vicinity of an amateur radio operator who operated in the 15 meter band (21.000 to 21.450 MHz). The fundamental signal could find its way into the television's IF stages and could cause interference even though the amateur was operating legally. Alternately, 3rd order harmonics from 7 MHz transmissions could cause TVI for the same reason. If the problem could not be rectified technically, it was usually best for the operator to cease operations so as to maintain a good relationship with the neighbor. The extent of interference to television IFs is not known at this time but it is believed to be the exception rather than the rule.
Later on, this ceased to be a problem when televisions were designed with a 41.25 MHz IF for the sound and 45.75 MHz for the video IF.
In an effort to reduce cost, transformerless TV designs found their way into the marketplace. This had the effect of launching new families of standard vacuum tubes whose filaments ran on what some might call "odd voltages". Types 2FH5, 4AU6 and 10DR7 are just three examples of tubes that could be found in the series filament string in a transformerless TV. In a 5 tube transformerless radio, it's very easy to find a tube with an open filament. It must have been very challenging when a service technician was confronted with a transformerless TV having perhaps 20 tubes whose filaments were wired in series.
Nuvistor tubes, designed by RCA in 1959, were widely used throughout the 1960s in television sets beginning with RCA's "New Vista" line of color sets in 1961.
In 1960 the General Electric company combined multiple common tube types into "fat" tubes—as many as four in a single glass envelope, all heated from the same filament. The idea was to reduce the amount of power required to heat the tubes and the space they required on the circuit board, as well as the associated costs of multiple sockets. In truth, they were designed almost completely for the colour TV market. This was the apex of TV design using vacuum tubes.
By the 1970s, hybrid designs started appearing. The receiver portion of the television would be composed of solid state circuits while the vertical and horizontal circuitry still retained vacuum tubes. As semiconductors improved, televisions became totally solid state except for the CRT. Controls started to disappear being replaced with pushbuttons and on-screen menus.
When TVs were 100% vacuum tube, it took nearly 30 seconds for the tube filaments to come up to operating temperature after the set was powered up. In fact, this was the norm for all vacuum tube equipment. When TVs went solid state but still used CRTs, the only tube left with a filament was of course, the picture tube. To reduce the warmup time of the CRT filament, manufacturers designed a “standby” mode whereby a reduced filament voltage was applied to the CRT when the set was powered off. This reduced the warm-up time to less than 10 seconds.
Probably the biggest innovation in TV technology was the introduction of colour broadcasting in the early 1950s . The initial proposal by CBS for a colour TV standard was incompatible with the existing base of black/white TVs so the FCC would not approve this standard. A short while later a compatible standard was developed whereby the black/white sets simply ignored the luminance and chrominance information found in the colour signal.
Colour TV was introduced in Canada on Sept. 1, 1966. Canada was the third country in the world to get colour TV, after the United States in 1953 and Japan in the early '60s. High prices for colour televisions and the scarcity of color programming greatly slowed its acceptance in the marketplace. It was not until the mid-1960s that color sets started selling in large numbers in the US, due in part to the color transition of 1965 in which it was announced that over half of all network prime time programming would be broadcast in color that autumn. The first all color prime time season came just one year later.
Most early monochrome TV sets had the following controls: Volume ; Channel Selector; Fine Tuning , Brightness; Contrast; Horizontal Hold and Vertical Hold. These were all accessible to the viewer.
It was not uncommon to frequently readjust the horizontal or vertical hold controls to either keep the picture from breaking up or rolling respectively. The vertical hold control was usually nested with the set's front or side panel controls while the horizontal hold might be at the back of the set or elsewhere. When channels were changed, it might require that the Fine Tuning control be adjusted. As better circuitry found its way into TV designs, it rendered the fine tuning, vertical hold and horizontal hold controls obsolete.
In the era of vacuum tubes, all equipment had to be handcrafted. Robotic assembly of circuit boards had yet to be invented. As a result, televisions were very expensive in the 1950s and 60s when compared with the average factory wage of the era. Using one handy example , a 21 inch Simpson Sears Silvertone television cost $Cdn 295 in 1955. To a factory worker making a wage of a dollar an hour, this meant that it took 295 hours of labour to pay for the set. Had manufacturing techniques and technology not changed, that very same TV would cost $2,728 in 2017 when inflation was factored in. Compare that to today's TV cost versus wages and it can be seen that it only takes 20 to 40 hours of labour to pay for a medium sized flat screen TV in 2017.
Until the arrival of flat screen TVs, several significant developments helped to drive down manufacturing costs. First came the introduction of printed circuit boards. Tubes sockets could now be soldered directly to the board thus eliminating the need to wire up filament strings. The
introduction of Compactron tubes reduced the tube count. Solid state was probably the biggest factor in driving down cost as well as the use of plastic cabinets to replace wood.
There is an abundant amount of material available on the Internet about specific television programming. Therefore, it is the intent here to generalize on the scheduling of the programming.
In the beginning, television broadcasts were not 7/24 because there was not enough programming and viewership to fill the available time. Most stations signed off at midnight and didn't resume until morning. Stations usually broadcast the “Indian head” test pattern in order that technicians could make transmitter adjustments, After checks were completed the station would stop transmitting until the usual 06:00 hours start of programming.
The Indian-head test pattern is a black and white television test pattern which was introduced in 1939 by RCA of Harrison, New Jersey. It was also used in Canada, following the Canadian national anthem sign-off in the late evening.
During the late 1950s, the test pattern gradually began to be seen less frequently, after fewer sign-offs, on fewer stations, and for shorter periods in the morning, since new and improved TV broadcast equipment required less adjusting. In later years the test pattern was transmitted for as little as a minute after studio sign-off while the transmitter engineer logged required Federal Communications Commission-US/Industry Canada transmitter readings, and then turned off the power. Towards the end of the Indian-head TV era, around the late 1970s, there was no nightly test pattern on some stations, when automatic logging and remote transmitter controls allowed shutdown of power immediately after the formal sign-off.
After an immediate transmitter power off, in lieu of the Indian-head test pattern and its sine wave tone, a TV viewer heard a loud audio hiss and saw “snow” on the TV screen. When US broadcasters transitioned to color television, the SMPTE color bars superseded the black-and-white test pattern image.
In general, the programming of the 1950s and 60s could be slotted into three groups. News and game shows were featured in the morning; soap operas in the afternoon and prime time programs in the evening hours between 20:00 and 23:00 hours. Westerns, police dramas and variety shows made for popular viewing during prime time.
Program listings were published in TV Guide whose first issue was released on April 3, 1953 in the US. Prior to that time, listings were published in local viewing areas. As an example, Lee Wagner (1910–1993) who was the circulation director of MacFadden Publications in New York City, printed a New York City area listings magazine in 1948 called "The TeleVision Guide". In Canada, TV Guide originated as a domestic version of the American TV Guide before being spun off into a separate print publication that was published from 1977 to 2006, at which point it ceased publishing and its content was migrated entirely to a web site.
An example of a local programming listing is the one below published by the Dumont Television company for station W2XBS in New Your City for the week of March 17, 1940. W2XBS was, founded by the Radio Corporation of America (a co-founder of the National Broadcasting Company), in 1928. W2XBS used a low definition mechanical television scanning system and later was used mostly for reception and interference tests. The listing is intended to provide a sampling of programming in at least one area. It is not known at this time if Canadians living near US border cities were able to receive such programming in 1940 but if they could, this is what it might have looked like.
to enlarge. This is an image of the whole Dumont listing. Programming started
either in the late afternoons or early/late evenings. This schedule
measured 18" x 20". W2XBS used a 60 line scanning system in 1931 then upgrading
to 441 line broadcast by 1938. In 1942, it received a commercial license
|Click to enlarge. Note that there were no programs on Tuesdays. Programs were also limited in quantity. W2XBS used the same call sign format as the amateur radio community. and transmitted on the now obsolete Channel 1.|
|Listing from the collection of Tom Genova|
After the first Canadian stations (CBFT in Montreal and CBLT in Toronto) came on the air in September 1952, television developed differently in Canada than in the United States because it was introduced and developed in a different context. The distinct social, political, and economic situation of Canada shaped the historic development of mass communication and television in the country. In spite of this, most media in Canada is strongly influenced by media in the United States.
A lot of early television was live because a cost effective video recorder had not yet been commercially developed. The first commercial video recorder, the Ampex VRX-1000, did not make its debut until 1956. Because of its US$50,000 price at the time, the recorder could only be afforded by the television networks and the largest individual stations.
Whatever happened to Channel 1? During the era of experimental TV, Channel 1 was moved around the lower VHF spectrum repeatedly, with the entire band displaced upward at one point due to an early 40 MHz allocation for the FM broadcast band. FM was moved to its current frequencies in 1946. TV Channel 1 was last allocated to the 44 to 50 MHz band before disappearing from the dial on June 14, 1948. The vacancy was re-allocated to fixed and mobile services.
In the US, mechanical scanning methods were used in the earliest television systems in the 1920s and 1930s. They broadcast in the 2 to 3 MHz band until the FCC created allotments in the 40 MHz band. The vacated spectrum was then re-assigned as the Police band. One mechanical TV system used 48 line images. Next came 60 line images . All mechanical television was considered to be "experimental". By 1935, low definition electromechanical television broadcasting had ceased in the United States except for a handful of stations run by public universities that continued operating up to 1939. The Federal Communications Commission (FCC) saw television as being in a continual flux of development with no consistent technical standards, hence all such stations in the U.S. were granted only experimental and non-commercial licenses. This hampered television's economic development. Obsolescence was "easy" to handle in those days because TV set sales to the public did not begin (in earnest) until the post war period. The various experimental standards only affected a small number of laboratory sets and a small number of "field" test sets ( perhaps in the low hundreds). In Canada, it would have been a similar situation for the elite few who could even afford to buy a set to receive experimental American broadcasts.
All-electronic scanning television, first demonstrated in September 1927 in San Francisco by Philo Farnsworth, and then publicly by Farnsworth at the Franklin Institute in Philadelphia in 1934, was rapidly overtaking mechanical television. Farnsworth's system was first used for broadcasting in 1936, starting at 400 lines to more than 600 lines with fast field scan rates. In 1939, RCA paid Farnsworth $1 million for his patents after ten years of litigation RCA began to demonstrate all-electronic television at the 1939 World's Fair in New York City. The last mechanical television broadcasts ended in 1939 at stations run by a handful of public universities in the United States.
Field tests in Los Angeles on various electronic scanning systems began in 1936. By 1938, the United States adapted RCA's 441 line system .RCA had also evaluated 240 and 343 line electronic scanning before settling on 441 lines. The system was publicly launched by NBC during the New York World's Fair. Because Canadian television came after US television, Canadians did not have to go through the phase of experimental, mechanical televisions. The 525 line NTSC standard replaced the 441 line standard on July 1, 1941 and opened up the door to the mass production of televisions after WWII in both Canada and the US.
Early televisions had tube counts around 20 to 22. With that many tubes, the Mean Time To Failure decreased so tubes had to be replaced occasionally. The stages most prone to tube failure were the low voltage rectifier and the horizontal output stage. When the television went kaput, the viewer would typically call up their favourite TV repair shop and place a service call. A technician would then show up at the front door with a tube caddy. This was a wooden case with two clamshell type storage areas in the top third of the case. These clamshells would be stocked with the most popular types of tubes . At the bottom of the caddy, there was space for tools or additional tubes.
Based on experience and symptom recognition, the tech would substitute the most likely failed tube. The tube substitution method was the most foolproof one especially when dealing with a tube in the receiver's RF stages. If the tech did not have a tube to substitute, it meant a trip back to the shop. For faults that could not be repaired in the viewers home, the tech pulled the chassis out of the cabinet in order to bring it back to the shop for a bench repair. That meant the household would be without a set until the chassis was repaired.
Often, a television owner would become very concerned if the sound was OK but there was no light being emitted from the picture tube. Many folks thought that the picture tube went defective. A good technician would assure the owner that the picture tube was the very last one to go.
Just like Saturday morning car mechanics, the TV world also had do-it-yourself folks (DIY) who tackled TV repair. They would look at a symptom chart which would tell them the most likely tubes to check. The suspect tubes would then be taken to a drugstore which was fitted with a tube tester. This was a commonly found arrangement in the 1950s and 60s. The tubes would then be tested and if one was found to be bad, the customer could purchase a new tube from the stock of tubes stored directly below the tester. Rumor has it that the drugstore emission type tube testers were biased to show many tubes as being weak or bad when in fact they were perfectly good. However, this can not be collaborated anywhere. With the advent of solid state TV design came the mass disappearance of TV repair technicians, TV repair shops, drug store tube testers and Do-It-Yourselfs. There is however, a limited amount of work with respect to warranty repair of TVs.
Pre-1941 TVs used amplitude modulated sound. The NTSC standard of 1941 recommended that TV sound be frequency modulated. Initially sets were designed to receive FM monaural signals having a maximum deviation of +- 25 KHz, unlike the FM broadcast band where permissible signal deviation is +/- 75 KHz.
Multichannel television sound, better known as MTS is the method of encoding three additional channels of audio into an NTSC-format audio carrier. It was adopted by the FCC as the United States standard for stereo television transmission in 1984. Sporadic network transmission of stereo audio began on NBC on July 26, 1984, with The Tonight Show starring Johnny Carson - although at the time, only the network's New York City flagship station, WNBC, had stereo broadcast capability .Regular stereo transmission of programs began in 1985. Canada soon followed suit.
In older TVs, there was sufficient space to install proper permanent magnet speakers in the cabinet. In many of the new flat screen TVs there is insufficient depth to facilitate proper, inboard speakers. As a result the audio can sound somewhat "tinny" since the internal speakers are too small. To address this problem, the viewer must hook up an external audio amplifier in order to maintain good audio fidelity.
Early electro-mechanical tuners in televisions consisted of ganged wafer switches which had contacts that were used to select different taps on a coil thus tuning the receiver to different stations. Each time the viewer wanted to receive another station, the tuner dial would have to be rotated. Over time, the contacts would become intermittent and the tuner dial would have to be jiggled until the station was tuned in. In real bad cases, a wedge of paper in behind the dial would stabilize reception. In addition, the tuner dial had a larger dial surrounding it. This was the fine tuning dial. If a newly selected station was on the verge of breaking up, the viewer had to adjust the fine tuning until the picture came clear. It was therefore not surprising that early televisions only had a life expectancy of perhaps 10 years before a seriously intermittent tuner caused the set to be scrapped. In the 1980s, tuners became all electronic. Gone was the clunk, clunk, clunk sound of the mechanical tuner.
When UHF television came into being, the FCC allocated channels 14 to 83. The All-Channels Act was passed by the United States Congress in 1961, to allow the Federal Communications Commission to require that all television set manufacturers must include UHF tuners, so that new UHF-band TV stations could be received by the public. This was a problem at the time since the major TV networks were well-established on VHF, while many local-only stations on UHF were struggling for survival. Canadian TV production and programming followed suit.
In 1983, the US FCC removed channels 70 through 83 and reassigned them to Land Mobile Radio System. Television production in Canada made the necessary changes to conform with the US allocations.
Television history is a very broad subject and one which is not possible to adequately discuss in such a short narrative. Readers are encouraged to Google any of the above topics that they find of interest.
17) Tom Genova USA <tgenova(at)gmail.com>