This exhibit is a solid state replacement for the DY87 type of EHT rectifier. There is no continuity between the heater pins and without an internal dummy load it can be used to replace rectifiers with different heater requirements such as the 1.4 Volt DY87 and the 6.3 Volt EY87.
The DY87 is a television EHT rectifier introduced in 1956. It was designed to have its heater supply produced by an over-wind on the line output transformer. The 18,000 Volt rating places this as a rectifier for medium sized monochrome televisions.
The reverse is plain. The seam and depression indicate an injection moulded case. Inside will be a series of diodes.
The top cap.
The B9A base pins.
The original box showing the range of rectifiers it replaces.
Thanks to Phil Harris G4SPZ for donating this exhibit.
The thin glass tube envelope is 21 mm in diameter, and excluding the B9A base pins is 67 mm tall.