Early-1948 Zenith Model 7H820-U. Complete Electronic and Aesthetic Restoration Outstanding Performance. Here is another beautiful example of a fully-serviced Zenith model. 7H820-U (we have restored four so far). This specific model is one of the more. Historically-significant radios produced by Zenith during the 1940′s. Eye-catching art-deco appeal with a very capable radio receiver and delivers rich, room-filling sound courtesy of the large full-range speaker and a newer phase-control tone adjustment system. We have restored this set to its original working condition, and it pulls in even weak stations very clearly across all three of the frequency bands since all components that were aged beyond their useful life have been replaced, and each section of the radio’s circuitry has been carefully re-tuned to attain optimal performance. The housing is vintage mahogany marbled Bakelite with little wear – it is difficult to find a specimen of this model with a housing in this good of a condition. The brass nameplate on the speaker is untarnished, all knobs are original, and the dial face and original speaker are in very good condition. There are four reasons why the 7H820-U has so much history behind it compared to the other two “look-alike” Zenith models 7H820-Z, and 7H920. To be designed with a. Large speaker with the signature tone control or tuning dial in the middle, a design that started a trend for the next decade. It was the first Zenith to use the. Smaller “miniature tubes” that would soon become the mainstay of vacuum tube electronics. The first Zenith model to use a. Solid-state component (a selenium rectifier). Modern FM broadcast bands in one set. Between 1941 and 1948, the original FM broadcast band in the USA was. 42-49 MHz (called “FM-45″). A network of hundreds of stations developed by Edwin Armstrong. But in late 1948, RCA (heavily invested in television) successfully pressured the Federal Communication Commission to re-allocate the FM-45 frequencies for use in television broadcasting (the FM-45 frequency block was used for the picture and audio signal for TV Channel 1), and all existing FM-45 radio stations were forced off the air or to move to the new. 88-108 MHz (“FM-100″) band that we’re familiar with today. 2 years later, the FCC took the 42-49 MHz spectrum back from television broadcasting and reassigned it for mobile-service communications (like police and taxis) – this is why TV’s made after 1950 start at Channel 2, and not Channel 1. During the short “limbo period”. Hile the FCC was still deciding whether to turn the FM-45 band into TV spectrum, radio manufacturers didn’t know which FM band to put in their radios, so a few simply decided to manufacture them with both FM-45 and FM-100. This Zenith 7H820-U is one of these. This is also why you don’t find vintage RCA-Victor radios with FM-45. Today, you can still hear other things on the FM-45 frequency band with this radio – your baby monitor, intercoms, walkie-talkies, and in many jurisdictions, Highway Patrol radio communications, taxis, construction, and 2-way communications for private companies. A great deal of time and detailed attention went into restoring this radio so that it provides you with years of listening and aesthetic enjoyment. Several of the key steps performed to create a quality and enduring restoration were. Housing, knobs, and dial scale completely cleaned and polished; any very obvious scratches removed. Electrolytic capacitors replaced with brand new modern capacitors. All wax-paper capacitors were replaced with new modern equivalents. Silver mica capacitors inside discriminator stage RF transformer removed, cleaned of oxides, and replaced. Selenium rectifier replaced with a modern silicon rectifier and resistor for safety. All electrical contacts and tube sockets cleaned of oxidation and treated to remove and retard oxidation. Tuning assembly, wheel, and variable capacitor gangs cleaned and adjusted, mounts replaced. Dial lamp and socket assembly replaced. Both dial cords replaced and tensions adjusted. Tubes checked and two under-performing tubes were replaced. Several resistors markedly out-of-tolerance replaced. For all 3 frequency bands, performed tracking and alignment of all RF stages and antenna circuits to provide peak sensitivity and selectivity across entire tuning range. Replaced all wires with crumbling rubber-insulation under chassis. Fuse added to AC power input for safety. Brand new polarized power cord and plug installed for safety. Rheostat and switch assemblies manually cleaned and treated to provide noise-free operation and protection against oxidation. Volume control rheostat and switch assembly replaced. Chassis cleaned and treated to remove and retard oxidation. Replaced speaker grille cloth. Reproduction labels for band switch and volume applied. Reproduction tube diagram label affixed to bottom of radio. Small fissure on lower rear-left side and tiny chip on rim of speaker dial face repaired with Bakelite-impregnated resin (barely noticeable). Radio tested for several hours over multiple weeks to ensure consistent operation. We will also include a copy of the original Photofact service manual for the Zenith 7H820, which includes all schematics, parts lists, and alignment procedures for this specific radio so you can maintain or repair the set yourself. This radio is sure to become a centerpiece for your collection, or a perfect accent to any room. Your radio will be double-boxed and carefully packed so that you safely receive it. Please feel free to ask any questions you may have – we answer every question in detail. Thank you for looking! Notes: Fed Ex ® is our preferred carrier because we’ve never had any problems with damage compared to other carriers. We pack our radios very carefully (far too much work has been invested in each radio’s restoration to have a carrier damage it in transit). In the very rare instance your radio arrives damaged or in non-working order, we will work with you to troubleshoot or correct the problem to your satisfaction. In addition to the fragile nature of vintage electronics, they operate at higher voltages – user assumes all risks. We have integrated several safety implements into your set making it much safer for everyday use than when it originally came off the factory assembly line. The item “Restored Working ZENITH 7H820-U AM & Dual FM Antique Vintage Bakelite Tube Radio” is in sale since Tuesday, February 21, 2017. This item is in the category “Collectibles\Radio, Phonograph, TV, Phone\Radios\Tube Radios\1930-49″. The seller is “adeliepenguin” and is located in Buras, Louisiana. This item can be shipped to United States, to Canada, to United Kingdom, DK, RO, SK, BG, CZ, FI, HU, LV, LT, MT, EE, to Australia, GR, PT, CY, SI, to Japan, SE, KR, to Taiwan, TH, to Belgium, to France, to Hong Kong, to Ireland, to Netherlands, PL, to Spain, to Italy, to Germany, to Austria, RU, IL, to Mexico, to New Zealand, SG, to Switzerland, NO, SA, AE, QA, KW, BH, HR.
- Country/Region of Manufacture: United States
- Brand: Zenith
- Model Number: 7H820-U
- Year: 1948
- Housing: Bakelite
- Color: Mahogany
- AM (Mediumwave) Frequency Band: 530-1620kHz
- FM-45 Frequency Band: 42-49MHz
- FM-100 Frequency Band: 88-108MHz
- Power Supply: 117V AC (50-60Hz) or DC
- Weight: 12lbs (5.4kg)
- Chassis: 7E01
- Size (WxHxD): 14.75 x 8.25 x 7.5 in (36.5 x 21.5 x 19.5 cm)
