Visual Diagnostics (PC Engine)

many common problems can be seen by having a specific type of screen output below are some common errors that might be quicker identified by their visual appearance inverted / red overlay appearance initially looking as if there is an over wash of red , or lack of blue/green (although blue and green do still both appear), this has been known to be caused by a bad hu6270 (cpu) , specifically the pin 32 (vd2) that was faulty and required a new cpu notice how it looks compared to a working cpu below