You can replace just the picture tube saving the electronics:
http://arcademonitor.com/Arcade-Monitor-Parts/Please before working on this watch Johns video on discharge the current monitor first before working on it. Changing the tube is pretty simple but you have to discharge it first even if its been off for awhile. IT can severely hurt or injury you, or kill you. But its easy to do it, just follow John here:
https://www.youtube.com/watch?v=YfQbdvB8GSMGood Luck!
-Greg
P.S. Adding if this is a Vector monitor (Tempest, Asteroids, Battle zone, Star wars, etc), then you need to add a resister or use a HV probe to discharge it slowly vs a quick discharge. If you dont know post the game name up here or just look at the writing on the monitor and Google it.