That's the problem with trying to repair these things. Resolder the power board. Reinstall it. Nope! That didn't work. Replace the convergence ICs. Reinstall that. Nope! That didn't work. Maybe it's the video board or the deflection board. And before you know it you've spent a lot of money and it still doesn't work. Even if all that gets the set working, how long before something else goes out? On a set that's 10 or more years old, there could be another failure just waiting around the corner. I didn't want to take that gamble and even if I did what would I have if it did all work out? Technology that's 10 years old and getting older every day for probably about the same it would have cost to buy a new TV.
You run into the same decision tree with anything: tv, car, refrigerator; any major purchase eventually needs to be replaced with another major purchase. There are people who have classic cars and think they're wonderful. Not my cup of tea, but I do think my RPCRT is better than anything else that I've seen. And I've put in a bit of time and money over the years.
Be careful taking everything apart. And good luck in your search for a replacement.