264. The raster scan RADAR display has missing video in a rectangular block on the screen. Where is the most likely problem area?

A rectangular block of missing video on a raster scan radar display most likely indicates a failure within the video memory area. This type of failure corresponds to a block of memory addresses and results in a distinct rectangular pattern, unlike sweep or power issues which typically affect larger portions of the display. Memory stores radar echoes before they are displayed, and a localized memory fault manifests as a rectangular absence on the screen.