Got a used monitor - has some issues, help me fix - also questions on convergence adj
 

I picked up a sony bvm-1310 yesterday for $50 .. this thing cost over $5k when new so i was willing to get it w/ some issues :)

basically upon close inspection, it appears that it was either dropped or hit on a side. one of the pull-out boards (the one on the left) had signs of physical damage on the corner .. the retaining clip was bent and a piece of protective plastic cracked. For the most part, the picture is fine, but there is a vertical convergence problem.. i spent a good hour and a half or so playing with convergence adjustments yesterday - for those that dont have the monitor and arent fimliar with its setup, one of the pull-out boards has a matrix of 3 x 5 trimmers that you can turn to adjust convergence on any part of the screen (2 matrices - one for vertical, one for horizontal)

I also noticed that 9 of the holes were marked numericaly and i'm assuming thats the order in which you should adjust it ... welll after over an hour of tweaking, i was able to get it somewhat decent but not perfect. Initially, when i brought it home, the bottom left corner was really bad (red and blue were separated by maybe 1/5 to 1/4 of an inch ... once i balanced it all, the separation is much smaller.. probably within 1/16 but now i have a tiny bit of separation in the center area as well.. this is visible on a pin pattern but on a live pictures it's not that bad.
question is - is there anything more i can do - is there finer adjustment available directly on the tube or anywhere on the inside of the monitor. I have sufficient experience with electronics that I dont mind picking the thing apart if it means returning a $50 monitor to its $5k glory :)

any help with this or just general tips on convergence adjustment would be much appreciated
Thanks!