I agree, capacitors are so much less reliable than a crystal, I'd suspect them before anything else. I have replaced bad electrolytic caps in equipment made as recently as the 1980s, and found MANY more bad caps (electrolytic and other types) in 1960s-era TVs.
When I had a color sync issue in my CT-100, I got my hands on some old-school crystals and tried substituting them. I eventually concluded the crystal was not the problem, and today it's running with its original crystal.
Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html