Viewfinder image intermittent

Hi, I have a Zeiss OCT and the viewfinder camera image doesn't stay up consistently. It won't disappear during a scan, only when left idle for a while. In it's place is a white screen with the brightness and contrast settings, the same screen that shows up for a few seconds as the system first goes into scan mode. So far, the image has been coming back up when I reboot the system (Windows 2000 Pro). Software version is Stratus 7.0.0 I don't know if it's something in the head where the camera is, an issue with the CPU port, or something else. Any advice, links to service info, etc would be greatly appreciated.