Tube size question
 

My understanding is that the WTDS indicates the visible size in centimeters. However, the Wells-Gardner D9205 monitor is described as being "33 inches," but has an A80AEJ15X08 tube in it, which is 31.49". 6That's quite a bit less than I'd expect would get rounded up to 33".

Is there something I'm missing here? Perhaps the size is measured laying directly across the screen, which would add an inch or so due to the curve of the face.

Where are you? US, Canada or Europe? All have their own conventions for viewable area. Some even require the square viewable area to be stated.

US - it's the diagonal viewable area, as defined by US Code from 1967, first used in 1968 model adverts.

Canada/Europe - I honestly don't know.

A80 CRTs in the US are 32", A63 is 25", and A91 is 36". Rounding is allowed. :D

I'm in the US, so was Wells. I'm aware of the differences by country, but most of the specs I've seen for things using WTDS tubes have roughly followed what you stated. The 33" is the first exception I've found, so I was just curious why that was.

Maybe what you have is a post-sale-to-consumer Canadian import...The canucks never passed the screen size laws we did so their tubes are usually labeled as ~2" bigger than the same tube was here in the USA.

I am not sure if monitor tube sizes in the US were required to be stated as viewable diagonal rather than over-all diagonal at the same time as TV tubes. Anyone recall?