Fix'n VT220s

I recently "saved" a small pile of VT220 and VT100 terminals from a barn in western WI. They were grubby and have various issues but I am enjoying cleaning them up and making a few good ones from some bad ones. One of the VT220 is a very new vintage unit. Circa-1987, with some components with date codes 1990. It has a totally different logic board than earlier models I've worked on-- this one having a large PLCC package in the center of the board which I assume is a custom device integrating the video controller and much of the support logic since there are considerably fewer parts on this board than the older ones. Still an 8031 CPU though. This unit also has a totally different video monitor circuit than the older ones and my problem lies somewhere on that board-- I am getting a very dim image even though the CRT itself appears to be in very good shape with no burn-in and otherwise crisp display. I think I've got a high-voltage problem but without schematics to match this board, it's kind of a crap shoot to start debugging. So, wondering if anyone has newer schematics or technical reference for the VT220 than we find out on bitsavers? The bitsavers docs are circa- 1983 so I am looking for something 1987 or later when it appears they did a considerable redesign of the guts of this terminal. Chris -- Chris Elmquist