The CV1097 seen here was purchased in around 1965 for an oscilloscope project. The cost was 28/- (28 Shillings or £1.8.0). It was wrapped in carpet inside a vacuum cleaner box and placed in my parents roof when I went to college. It transferred to our roof in 1978 and was brought out in 2020 to be photographed. It has never been used.
The 6 inch green phosphor cathode ray tube was designed especially for WWII airborne radar and the prototype was the VCR97. It was first used in 1940 in the ASV range amplitude display. The phosphor type is P1 medium persistence green. The CV2810 is the same tube but with a short persistence violet phosphor beneath a longer persistence green phosphor.
The plastic rings - seen near the base cap - were present to keep the mu-metal magnetic shield away from the glass.
The CV2286 is very similar physically but has an EHT connector on the side of the bell. This may be to connect to the final anode or it could be an early example of post deflection acceleration.
An advert for Premier Radio in Wireless World August, 1948 confirms that the VCR97 is equal to the Mullard ECR60.
Pin 7 is the internal graphite 'Aquadag'coating. The design specification is for A1, A3 and the coating to be tied together and manufacturers could elect to do this at manufacturing stage. The connection would be to pin 10 as the final anode.
The heater cathode insulation was not designed to withstand high voltages and so the heater supply would be floating. The standard practice was to hold the final anode at earth potential or that of the deflection amplifier HT rail. This leaves the cathode at about 2.5 kV below ground.
The electron gun, flared Y plates, B12D base and internal graphite coating as the final anode.
A closer view of the gun and first deflector plates.
The B12D base. Inside is the evacuation tube. A common fault in later years was that the wires would corrode and break from the connector. With care, and avoiding the evacuation seal, they could be re-attached.
The rods and mica discs that hold the components in alignment.
The curved face-plate has an overall diameter of 157 mm.