[Q] Black Screen DPI Change topic

hello. when using any rom whether it be aosp cm or stock, if i make a change to the dpi with the build.prop file in system folder, upon reboot i get a black screen. the boot lg splash screen shows then at the rom boot animation the screen goes black like it just turns off and i cant get it to respond. the led light flashes green at this time. this happens with any rom that i try to do this with. is that happening to anyone else? do you think this could be the early stages of my screen going bad? if i reflash the roms to stock 480 dpi then it works fine.