AppleColor RGB Monitor (IIGS) help?

Hi, Just thought I'd ask if anyone has the service info for the standard IIGS colour monitor (official name seems to be "Applecolor RGB Monitor"), in this case A2M6014X. A bit of background: When I tried to start up my IIGS a few days ago, I was disappointed to get no life out of the monitor (though a spare composite monitor was OK for temporary use). Signs pointed to a fairly easy fix; the power supply seemed OK, it had HV, I could hear it syncing when I turned the IIGS off and on. So, I put it on my workbench, grabbed the schematics (http://apple2.info/downloads), and realised that I couldn't remember much about how this works, but it's analog RGB, so how hard can it be? I wound the screen pot up a little, and was able to see scan on the screen; when I turned the IIGS on, the scan/retrace lines stabilised, so at least sync seems OK. Checking test points, I got a nice clean signal on the input (TP1R, G, B I think), and also at the output of the AN5356 interface (TP2R, G, B). But checking the drive at the tube socket, there was little to no activity, no trace of the almost digital-looking signal I was seeing on the other test points. However, I don't have a good understanding of the voltages I should expect to see at those test points, so the waveform may still not have been right. Any suggestions (or links to service info for this monitor) would be much appreciated! Or would I be better taking this to another list? I'm quite keen to improve my monitor troubleshooting knowledge, with the impending demise of CRT monitors and places to service them. Mike