Item Description
Allen B. Dumont Laboratories Cathode-Ray Oscillograph
here is an old timer, and it powers up!and the graph lights up a green "point" of light, I have no test leads however, but it seems like it will be fully functional, although the last calibration date is unknown, because this is a piece of equipment I acquired at auction along with other ham radio gear, and if you look at my feedback, it appears everybody that bought a piece of that ham gear, (that came along with this piece of equipment), from me has been quite satisfied...
 
 
 
 
 
 
 
 
 
 
Allen B. Dumont Cathode-Ray Oscillograph
 
Origins of DuMont DuMont started his company in late 1931 after leaving DeForest Radio Co. in Passaic, N. J., where he had been chief engineer and where he developed technology for manufacturing vacuum tubes and pursued television technology. DuMont's new company, in the basement of his home in Upper Montclair, N. J., began manufacturing cathode-ray tubes and later also made cathode-ray oscilloscopes. By 1937-38 the company was also becoming a major producer of TV receivers. It was first to introduce large-screen (14-inch) TVs and in 1939 had 14-inch sets at the New York World's Fair where others had 7-inch sets. Later, DuMont made a name in television transmitters and studio equipment and started a separate business, DuMont Broadcasting Corp., which operated television stations. It was sold in 1955 and later became Metro-Media Broadcasting. In early 1931, the year DuMont started his business, the General Radio Co. of Cambridge, Mass., (now GenRad of West Concord, Mass.) marketed the Electron Oscillograph, Type 535-A. (GR, as the company was known, didn't have model numbers; it had type numbers.) The 535 first used cathode-ray tubes made by Manfred von Ardenne in Germany, then later used CRTs made by Westinghouse. The instrument came in two parts. The CRT was mounted on a stand and the power supply in a separate cabinet. Since the company used its own sales force, not reps, it felt free to include price lists in its catalog. The CRT, its mounting stand and the power supply sold for $280. Before long, the company added, in a separate $170 box, the Type 506-A Bedell Sweep Circuit. It had been developed by Professor Frederick Bedell of Cornell University, a pivotal figure in the early world of oscilloscopes. At first, GR licensed the sweep-circuit patent from Bedell. Later it bought the pat ent, retained the instrument rights and sold the entertainment rights to RCA for use in television receivers. The General Radio 535, while it was the first scope from an important manufacturer and the first that almost everybody knew about, was not quite first. An earlier one was developed in 1927 by Bedell (yes, the same Bedell) and Herbert Reich of Cornell. A small number, estimates run from six to 12, were manufactured by R. C. Burt Scientific Laboratories of Pasadena, Calif. Robert Burt had been a scientist at Bell Labs in New York, a specialist in glass blowing for CRTs. He became a professor at CalTech and he married Eleanor Bedell, the professor's daughter. So Frederick Bedell was the most influential figure in early scopes. With Herbert Reich, he designed a scope at Cornell. A student who studied for his doctorate under Bedell, Thomas T. Goldsmith Jr., became DuMont's director of research in 1936. His son-in-law, Robert Burt, ran the first scope business, though it didn't last long and went al most unnoticed. And Bedell provided a sweep circuit for General Radio.