diagnosing an Intel Series II MDS monitor failure

A few weeks ago, while I was testing a spare IPB-80 CPU card in an Intel Series II MDS, the monitor stopped working, with the raster collapsing to a very bright dot in the center of the screen. I hit the power switch and pulled the line plug immediately, but the dot persisted for several minutes, only gradually dimming. I just started investigating it. With the monitor cable unplugged from the IOC board, the +15V DC at the IOC connector reads 0.74V. Of the two DC power supplies described in the service manual, this MDS uses the Power One. The +15V rail uses a separate transformer winding, a 723C regulator, a house-marked (12500-4) NPN pass transistor, and a zener and SCR crowbar. The 0.74V makes me think the crowbar has tripped and the 723 regulator is current limiting. Nothing else in the MDS uses the +15V supply. I was a bit lucky that this particular MDS used "method A" of installing the monitor, which makes it easier to remove. Once the metal shield is removed, the label was visible. It is a Ball Electronic Displays TV-120 monitor, which is a common enough model that it was easy to find the service manual online. I'll test the monitor on a lab power supply to see if it's drawing too much current. I may kludge up Rich Ottosen's PIC-based TV test pattern generator on a breadboard.