Allright, this is probably one of the most ringing misunderstandings about vector monitors.
Etienne is right. A tube is a tube. There is NOTHING (yes children, repeat after me, NOTHING) special about the TUBE in a vector monitor !
To understand WHY that is, you need to know what a picture tube does. Basically (for a BW tube) it does this:
1) the electron gun in the neck of the CRT shoots out a beam of electrons towards the screen
2) the electrons hit the phosphor on the screen and it lights up
That's it, that's all THE TUBE ITSELF does. Now if you would hook up a tube just like that,setting up HV to make the gun work and you would provide a constant voltage for the gun to show, you would of course only get one very bright spot in the center of the screen. In fact, that is what very often happens when vector monitors go defective, and this gives the well known burn spot in the middle if running too long.
But we can only get something meaningful from the electron gun when we make it move around the screen and to do that an electro-magnetic field is put around the neck which steers (or deflects) the electron beam. This field is controlled by the monitor electronics and makes it move in either a raster pattern (on a raster monitor) like this:
OR it makes the beam move "like crazy all over the place" with a vector set-up.
The differences are in the yoke that is around the neck of the bare tube (remember that, these are two loose elements, although the yoke of course is glued to the CRT to keep the picture stable) and the electronics driving the monitor.
So, if I take the tube from a raster device (like a TV) and put it in a vector monitor yoke and electronics, it will simply work as a vector monitor.
There are NO differences in production of tubes !!!
BUT I hear you say, some others say you DO need a special tube for certain vector monitors !
The answer is yes and no. In color vectors like the Amplifone, tubes with a 110 degree angle are used. The angle of the tube means the angle at which the beam needs to be deflected to reach the screen in the furthest edges. What it boils down to is that the higher the angle, the flatter the CRT is, so a 90 degr. tube has the electron guns much "deeper" away from the front of the tube.
Now, 110 degr. tubes are simply more rare than the more regular 90 degree tubes. If you open an 80's TV, you will likely find a 90 degr. tube and not a 110 degr.
You can't use a 90 degree tube on an Amplifone because the yoke is meant for 110.
Again, NOTHING else is different about these 110 degr. tubes and there _are_ TV sets that have them.
But but....what about the higher resolution of the Amplifone monitor ?Aha....that is an interesting question !
But simply answered: the dots of which the CRT's screen is built up are smaller on the med-res tubes used in Amplifone monitors compared to regular TV or monitor tubes. That's it. That gives it a (much) better picture compared to f.i. the WG6100.
This is also NOTHING special for "vectors" because a lot of later games also used med-res tubes in raster monitors, like 720 and Hard Drivin'.
So....if we go back to the BW tubes....the great thing about BW tubes is:
a) they ALL have the same pin-out
b) they do not need any convergence
So...I should be able to transplant the CRT from that TV into the vector chassis I got from Rémi and have a burn free picture
Now this is all just theory for me at the moment, but it will at least be a good practice before taking the dip in replacing a tube on a color vector monitor....
