I found this while doing a search, maybe it can help someone, Covers many years of older Graphtecs with some service manuals and some user manuals. Didn't know if posted before. I found their Parent Directory.
I noticed Graphtec pulled their service manuals, This is all that is there now.
http://www.graphtecamerica.com/support/cuttingplotters/firmware_cuttingplotters/
Graphtec had removed the service manuals from their page. but they can still be found online, by doing a search.. Most of the new models are.