Monitor won't stay on. When I turn the unit on it the picture will flash on for aboue 20 seconds then goes off. Repeatedly turning the unit off and on gets the same response. BUT sometimes it works just find. Have replaced the video card - no change. Once of the solutions talked about replacing a light/lamp(?) where, how, etc. I have taken it to a repair place and, of course, it went on just fine then. Can it be a bad on/off switch? And, if so how does it get replaced?
It is a component problem on one of the PCB printed circuit boards in your unit. Probably the Invertor or power board or power inverter or what ever its called. It is a common problem that there is a component like a capacitor or transistor or diode that goes bad and will need replacement. See this URL as an example. I understand it is not your make or model but it is the same symptoms.
OR similar but not the same (this might shed some light)
I have repaired this dell lcd using these instructions
Have you checked you video drivers? you may try annother monitor to check your computer for a video DRIVER type problem/incompatability. Was this a new monitor installed on your pc or did it work at one time on this same pc?
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