I cannot recall the model number right now. 7" Xenarc with LED backlighting. A couple years (2-3) since I purchased and installed.
Suddenly it has taken to showing display for a couple of seconds, the disappear. It won't return until I press the power button turning it off, then on again. Then it will stick around for a couple of seconds and go blank again. If I do this a few times, it might stay on for a while. Power light is still on when the display disappears.
VGA signal connections are tight.
Could this be the infamous ribbon cable issue I have read about? Is it time for yet another monitor?
is it a power supply issue?
Are you referring to the external power to the monitor or it's built-in circuits. The external supply is fine.
Sounds to me like a heat and/or bad soldering issue. Do some testing with some cooling spray (electronics safe) and see if it helps.