inspect the soldering work very carefully. I had a K7500 that I capped once (was my first one) where when I was trying to desolder a cap, I started desoldering parts around it and wound up hitting one of the transformers in the power supply section and forgot to solder it again (whoops).
that produced a fast ticking. with that desoldered, it couldn't make high voltage, which is my best guess. luckily after soldering it again, it magically worked.
sometimes with this hobby it's very easy to go after the more difficult and complicated stuff and ignore the very simple solution that sits right in front of you.
also check over the flyback solder joints real well. these chassis are very prone to easy damage of the solder pads, so just make sure they're all intact and are making contact with the traces they're supposed to connect to.