Television digest with AM-FM reports (Jan-Dec 1951)

tube had never been commercially produced, and the design was accomplished by using an entirely new type of construction. In the new 6V3 tube, the filament is suspended independently inside the cathode, without touching it at any point, and the cathode receives its heat by radiation from the filament rather than by conduction as in the ordinary tube. This new design makes it possible for the 6V3 to withstand pulse voltages well in excess of 6000 volts. This new tube design has already found other important applications. (2) With the new efficient deflection circuit, it is possible to use a new plate power supply similar to a design already successfully used by Philco. This new power supply utilizes two selenium rectifiers in a voltage doubler circuit and makes it possible to eliminate the heavy power transformer used in the conventional previous circuit. In the new power supply, a small transformer is employed to supply filament power; this transformer could also have been eliminated, but this would have required connecting the filaments of all tubes in series, and Philco engineers decided against such a design because of its obvious vulnerability. (3) A third major improvement in the new Philco TV chassis is the use of a newly developed cathode ray picture tube with electrostatic focus. By focusing the electron beam electrostatically, it has been possible to eliminate both previous types of focusers: the heavy permanent magnet focuser made of Alnico V; or the alternative, an electromagnetic focuser with a copper coil requiring a considerable amount of rectified power to energize it. In addition to these major design improvements, all of which also achieve substantial savings in critical materials, there are numerous other changes in the new Philco chassis which combine conservation and better performance. * ❖ ❖ Materials Savings Possible with New Philco Chassis Per Million Television Receivers New Chassis vs. Fall 1950 Sets Materials Savings in Pounds % Saved Alnico V 599,000 lbs. 100% Aluminum 563,000 68 Copper 1,263,000 26 Ferrite 529,000 51 Silicon Steel 7,397,000 58 Tin 80,260 50 Zinc 792,000 75 It should be noted that ultra-scarce cobalt is entirely eliminated, while the amount of other scarce materials needed is reduced by substantial percentages. Now to consider the specific details of savings under various headings. ALNICO V, which contains scarce cobalt, nickel, aluminum and copper as indicated, is entirely eliminated in the new chassis design, because of the following changes: (a) Permanent magnet speaker removed, and replaced by electromagnetic speaker. ' (b) Permanent magnet focuser removed; replaced by new electrostatic focusing circuit. (c) Beam bender of Alnico V removed; replaced with beam bender of Alnico III, containing no cobalt. ALUMINUM content of the new Philco chassis has been reduced by .563 lb. per receiver by the following changes: i (a) Aluminum frame assembly straps for picture tube I are replaced by fabric straps. ' (b) Aluminum protective cup for picture tube is re I placed by a plastic-and-fibre cup. (c) One electrolytic condenser, containing aluminum I foil, eliminated by use of electrostatic-focus picture tube. I (d) Amount of aluminum foil in other electrolytic con1 densers reduced by use of lower voltage plate power supply. ' COPPER used in the present TV chassis has been reI duced by the substantial total of 1.236 lbs. per receiver, even though it has been necessary to add copper wire for the electromagnetic speaker to eliminate Alnico V. Savings I of copper in the new design are achieved by: ' (a) Large power transformer is removed, and replaced with much smaller filament transformer and voltage doubler power supply using selenium rectifiers. (b) Amount of wire in audio output transformer reduced, with special compensation to maintain sound quality. (c) Wire used for hook-ups throughout chassis reduced from size No. 22 to No. 24. (d) Wire leads on tubular and mica condensers shortened. (e) Width and linearity coils removed because of use of new efficient deflection circuits. (f) Size of horizontal output transformer coil reduced through use of new circuits, including new 6V3 damper tube. (g) Copper ribbon-type ground straps removed and replaced by wire. FERRITE, which contains 20% nickel oxide and 25% zinc oxide, is a scarce material and the amount used in the new Philco chassis has been reduced 51% by the following changes: (a) Size of horizontal output transformer core reduced, thanks to new circuit and new 6V3 diode damper tube. (b) Ferrite core removed from deflection yoke; and replaced with new yoke of flake iron, which is a non-critical material. (c) Width and linearity control cores eliminated by use of new efficient circuits which include resistor-type width control and require no linearity control. SILICON STEEL is conserved in substantial quantity in the new chassis, which reduces the amount required per receiver by 7.399 lbs. by these changes: (a) Large power transformer removed, replaced by small filament transformer and voltage doubler power supply, with selenium rectifiers. (b) Size of audio transformer core reduced, maintaining high quality of sound output by special compensations. TIN will be conserved in considerable quantity in producing the new Philco chassis by using a new solder with 20% tin content, instead of the present solder with 40% tin; and by using a new flux with this solder to make permanent soldered joints. The resultant saving amounts to 80,260 lbs. of tin, a strategic material, per million TV receivers. ZINC is being conserved by means of eliminating some zinc die castings (notably one in the focuser); by the savings noted above under ferrite; and also by eliminating brass (an alloy of copper and zinc) wherever possible. All brass hardware and machine screw parts are being replaced with steel, wherever ferrous metals can be employed. The amount of brass in control bushings has been reduced about 10%;. All brass formerly used for decorative purposes on the cabinet is also being removed. CADMIUM, another scarce metal, is being conserved by changing the plating of the new deflection chassis and other metal parts to a plating of non-strategic materials wherever soldei’ing requirements permit. Total Weight Savings In view of the impressive list of changes enumerated above, it is not surprising that the new Philco TV chassis and picture-tube mounting frame weigh considerably less than the comparable current model now in production. It should be noted that ever since early 1950, Philco design has divided the chassis into two parts; one contains tuner, IF and other circuits; the second includes the power supply and associated circuits. The new design continues this highly efficient “duplex chassis” and achieves savings in critical materials — and weight — in both parts of the chassis, as well as in the picture tube frame assembly. Savings in Weight Achieved by New Philco Television Chassis R-F, I-P Chassis Section Power Chassis Section Frame Assembly, Yoke, Focuser Present Receiver 6 lbs. 15 oz. 28 lbs. 8 oz. 4 lbs. 3 oz. New Receiver 6 lbs. 3 oz. 18 lbs. 3 oz. 3 lbs. 2 oz. Totals 39 lbs. 10 oz. 27 lbs. 8 oz. Thus the new Philco design saves a total of 12 lbs. 2 oz. per receiver. This weight saving means not only a substantial conservation of critically scarce materials. It also means that new, lighter chassis will be easier to handle in production, thus reducing the fatigue of workers. Further the lighter chassis will appeal to future owners of the new 6