I guessed from your first message that you were North American, so keep in mind your set is very different from the European MX series. The good news is that there is a repair guide for these sets online for Silver/Gold members, together with the original Service Manual. We also have a Canadian member who is an expert and who has repaired his own set. Basically the problem is dozens of leaking capacitors. (Probably -- have you tried the STEP button instead of the button with a red dot on it? And unfortunately you won't get far without at least a used BeoLink 1000 remote from eBay.)
With HDTVs at current prices it's hard to say if any CRT is "worth" repairing. But this was a very special TV indeed -- ground-breaking in 1989, and it will deliver the best picture from a DVD you've probably ever seen on a non-HD set, partly because it was optimized for a high-quality 480i source (S-VHS) when introduced. The integration with other B&O audio equipment and speakers sold today is also stellar. I have owned two myself and my current one was rescued from just such a problem.
But the most important thing to say at this point is that TVs contain life-threatening voltages even when turned off or unplugged. The best bet would be for you to take the set to a qualified servicer, together with the Service Manual and repair guide, unless you have experience working with electronics...