Picture tube question

[jeyurkon]

We are fortunate to have someone like Don to correct our sometimes inaccurate advice. He's absolutely correct.

I didn't realize how much of an oddball these are, especially the 21FP4, until I looked up more detailed data-sheets.

On the other hand, if you asked about the 21FP4 because you already have one you might be able to use it to see if you have the set working while you search for a 21YP4.

My statement about a deflection angle of 65 degrees wasn't quite correct either. That is the horizontal deflection angle. The diagonal deflection angle is 70 degrees for both CRTs.

John

[kx250rider]

Originally Posted by jeyurkon

We are fortunate to have someone like Don to correct our sometimes inaccurate advice. He's absolutely correct.

I didn't realize how much of an oddball these are, especially the 21FP4, until I looked up more detailed data-sheets.

On the other hand, if you asked about the 21FP4 because you already have one you might be able to use it to see if you have the set working while you search for a 21YP4.

My statement about a deflection angle of 65 degrees wasn't quite correct either. That is the horizontal deflection angle. The diagonal deflection angle is 70 degrees for both CRTs.

John

I forgot about those cylindrical-face tubes too. Hoffman used a lot of those (21FP4?). It will leave a gap on the sides of the mask. Another one that gets me is the 20" (vs. 21") tube... You almost can't spot it unless you see the number. I got saddled with one of those from a rebuilder once, and wondered why the mounting band was so loose ... But to repeat, most any of these tubes will work, electrically.

Charles

[peverett]

I have some of the Hoffmans with the 21FP4. Luckily, all of my 21FP4s are usable. These are difficult to find. I did see a listing from Nebraska(I am in Texas) for one, but it is expensive and I am very afraid that it would be broken in shipping.

I have one Hoffman that uses a 19AP4(metal-glass). These are not just hard to find, but nearly IMPOSSIBLE to find in good condition.