|The no video input message doesn't necessarily indicate your power supply is "gone", unless it doesn't work at all.|
Some power supplies will shut themselves off when certain error conditions are encountered and will not start up again until the AC power has been removed to them for, say, at least 5 minutes, then they will start up fine.
You can get that message
- if your ram has a poor connection or is incompatible with your mboard (the mboard cannot boot normally).
- if you have both an onboard video port and at least one video port on a graphics card and you've got your monitor plugged into the wrong one (usually the onboard video port produces no video when a video card is installed in a PI-E X16 or AGP slot).
- if you have a mboard that has onboard video that has a main chipset that supports hybrid video and you have the monitor connected to a graphics card in a slot that has a video chipset that isn't supported by that feature (in that case the onboard video port is probably still producing video - you must change at least one bios setting to produce video from the video card in the slot).
Your power supply may not start up at all if you have a video card installed in a mboard slot that has a video chipset that requires your system has a recommended wattage capacity that is more than 50 watts more than the capacity your power supply has.