video wavy lines interference
I am using a laptop hooked up to a xenarc video monitor and I get wavy lines that looks like some kind of interference. I have spent much time researching this issue with no solution, I have seen others with the same problem, but also no real solution provided, I am hoping someone came up with a good solution. below is the scenario, methods already tested to correct, theory as to the problem.
laptop powered using a 12v to 18.5v laptop power converter (auto air adapter) mounted under rear seat.
xenarc monitor powered by direct line from car battery.
When running off laptop battery no lines image is fine, car running or not running.
I have tried adding noise suppress filter, ground loop adapter, tried grounding just about everything, monitor case, vga cable, laptop case, routed grounds to same location, and some various combinations of this. I have also tried 3 seperate power supplies air/auto, different manufacturers
after reading about others who had this problem, those who had desktops, using a power supply like opus were able to fix this problem by powering the monitor from the 12 volt out of the same power supply that was powering their pc. this, and the fact that it looks fine when running on battery power leads me to believe the lines are in fact caused because of some differential in the 2 power supplies, the car battery, and the laptop air/auto supply.
any ideas? i am stumped at the moment, looking for fresh ideas, how do most people power their laptops/external monitors, not using an ac inverter?