replaced my blue g70 tube recently and its has terrible focus. Its not mechanical its from the tube. Last tube aprt from the spot burn mark had great focus.
could it be cloudy glycol?.Should a new tube have bad focus? has anybody else had a similar problem?
it was purchased new through sony

I have not played with a Sony G in some time, but I had the same problem with my 9501LC when I replaced the tubes. I could not dial in the focus on the blue tube with the ring magnets. It ended up being the gain settings were much too high for the new tube. Check out your gain, contrast, and any other electronic settings you have.
Hope this helps.

def not gain settings.
becasue of the lack of focus i have to run the gain at 165 instead of the 255 as per the manual
i also dont get i very bright core and halo when i overfocus whist setting the electronic magnets ie beam focus
evrything is round etc but just dont get the bright core in overfocused state like i get on the other tubes

I had one like that too that was new through Sony. Unfortunately the guy that bought it let the return time window lapse and I had to replace it with one with about 300 hrs that was worlds better.

I would exchange it with Sony if at all possible.

Have you tested best position for focus yoke along neck?