The chassis is never completely dead...only tubes
A WG4600 will swap with no mods.
No No NO
Taking from the G08 Vector Monitor FAQ & Guide
If you are unfortunate enough to come across a G08 with a bad tube, there is still something you
can do about it.
You can replace the tube. As mentioned before, the tube is the same as the one used in the Wells-
Gardner 6100 series color XY monitors.
From Mark Jenison:
"I tried doing a tube swap with a 19VJTP22 tube from a Wells-Gardner monitor (4900 or 4600,
can't remember). I did not have any luck. While the picture was fine, I could not adjust out the
green band down the middle of the picture. Apparently this is due to the fact that the deflection coil
could not be positioned far enough down the neck tube (because the degree of the neck tubes are
different), but more importantly, the deflection coils are not angled to work well with a 90-degree
tube. I hear you can do this with a WG6100, which uses the same tube, but that's because it's
deflection coil is shaped slightly differently."
So you need a 19VLUP22 or a M48AAWO
I dont think anything else will work.