Cranky upon wakeup: 1 second on, 2 seconds off. Repeatedly.

The Mac Mini that it's attached to is generating a proper video image, since I can mouse and click and type productively during the two seconds of darkness, just not see where I've aimed at. I can avoid the issue if I don't let my CPU go to sleep, thereby forcing the monitor to run the screensaver all night. However, the Mac ran slightly funny the next day, so I slept it that night, and the next morning the monitor was worse. Each "off" was accompanied now by a "Chuff!" sound; this went on for several minutes, then switched to the prior type of "click," before eventually staying on. I have not yet located a flashlight. Will the test work in ambient light, or does the room need to be darkened?