Front view of the Line Shorter unit. It was the "T" unit. Behind the window, there were both Ignitron units. The original unit used tubes, but later station's personnel designed the transistorized one of the image. Original tube' schematic can be downloaded from here. This "T" unit grounded the 15Kv of the power supply in the case of an arc or overvoltage in any part of the transmitter. In the case of an arc or overvoltage in any part of a transmitter, whether it was the 1 or 2 of each series, when acting, the entire series fell. It's to say: If there was an overload in any section of the 7/1, when acting the ignitron the 7/2 was also disconnected, as the S1J was common to the entire serie.