I just checked my email and Rich (the guy I got it from) sent me an email and said the focus controls are on the flyback transformer. But I am so naive I dont know where that is...Yeah I know.
It will lead to the flyback. There are two knobs on it. One if for focus (should be the top one) the other is the brightness (it may have hot glue or silicone on it).
The flyback (or HVT = high voltage transformer...same thing) is the thing with the "suction cup" looking thing connected to the actual tube. Find the "suction cup" wire.....follow it back to what it runs to....that's the flyback. There should be two "knobs" on it. One is "screen" and the other is "focus". Screen and focus are stamped into the plastic housing. Shine a light on it to see which is which....adjust focus accordingly.