Here's the scope the 914 is used in:
RCA Model is TMV-168, also as Model 305. I don't have the data sheet handy, but I believe this weighed over 100lbs. Have been looking for one for a number of years, only seen one in a private collection.
Not a TV CRT, but the scope is wide bandwidth and was used for early TV work. One of them is listed in the inventory list for the 1939 Worlds Fair RCA demonstrations.
Now if you want to see a demonstration scope:
A DuMont Model 233, uses a 20" CRT (20AP1)
Chuck