Can you fix an electron gun?

Hi the blue beam in the electron gun of my tv is not working. Is there a fix for this?

As stated in a previous post my Tv is a Magnavox mptv68a the image is appearing with Red and Green colour blends. What should be white is yellow/green what should be blue is yellow.
Normally when the Tv is first switched on before my Xbox360 is turned on the background screen would be blue with MAgnavox appearing in Red. But there is no Blue at all just black.
The red and green 'out' resistors are working and as far as I can tell so is the Blue 'out' resistor.
So that leaves me with the electron gun. Is there a fix or should I dump this tv?

make sure the voltages on the tube are good for each color with the tube socket off if posible.you could also ground the pin on the crt socket which controls the blue voltage usually 145 to 190 volts you will get a bright flash of blue if the tube is good.you can also do the same with the red and green to see how bright the screen should be.if there is no blue flash then the tube is no good.the picture tubes are sealed and not repairable you would have to replace it

the problem is its hard to get picture tubes today sense there obsolete. you just can't go to any hardware store and pick a new one up like the old days. you can try searching online though i didn't find anything.

Hi thanks for your reply. Is there a diagram I can follow?