Amazing how cleaning tube pins magically cures mysterious problems
Yes, it's a good sign that the CRT lights up. It's capable of making some kind of a picture. You're getting some HV. And the sweep sections are trying to work.
Don't play the TV for more than a minute with that bright horizontal line, or you may burn a dark horizontal line in the CRT's phosphor that's impossible to fix.
If you feel compelled to play it anyway, turn down the brightness & contrast to make the line as dim as possible.
Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html