CloseView works on a Power Macintosh running System 7.5, but it does not magnify the Video Monitor window. Apple is aware and has it under investigation.
Workaround
You can view magnified video input using Apple Video Player and CloseView. This workaround does not work in thousands of colors, but it does work in 256 and 16 colors.
Please note that Apple Video Player has not been tested on a Power Macintosh and this configuration is not supported by Apple at this time.
Note: CloseView is written as a single word, not as Close View.