Looking at the chassis from the back there are is a 6 pin plug and just above that, a 3 pin plug in the upper left hand corner. Reading from right to left (still looking from the back) it goes RED, GREEN, BLUE, GND, V sync +, H sync+. the three plugs read blank, vsync -, h sync -.
Just hook up your cable so red goes to red etc. You should also have a h sync and a v sync on your monitor cable. These go to the v sync - and h sync- on the 3 pin plug.
If a cap kit hasn't been done --do one. This monitor went from a wavy washed out picture to a rock solid bright one with 5.00 in Caps (CDN!) I'm still amazed at the difference--and I can understand why the guy didn't want them to begin with

I also changed the v. lin and v. height pots since they cause distortion whenever i touched them.