You may need to bite the bullet and replace the remaining electrolytics, if you want your set to work well. So many of mine were bad that I quit bothering to test 'em after a while.
Swapping in a different board might or might not solve problems. If it's loaded with funky original electrolytics, they may fail at any time. Exchanging modules made sense when these TVs were new, but 50 years later you may just be installing a different set of bad components.
Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html