[Coco] CoCo2 lower graphics

[Michael Pittsley]

I have a COCO 2 that when I load certain software or cartridges the bottom
half the screen is garbled.   Knowing very little about the CoCo's hardware
I'm hoping someone may be able to assist me.  The garbled graphics is just
on some graphical games / cartridges.  If I load Tom Mix's Donkey King
everything works as expected.  Try to run a frogger game or Bridge Tutor, I
cannot see the bottom half of the screen other than gibberish graphics.  Now
I have another CoCo 2 that is essentially used for parts, only because when
I turn it on, I get a green screen but no "OK" screen.  Is there a video
chip in the CoCo 2 I can easily remove and replace with one from the parts
CoCo?  

 

-          Michael Pittsley

-          Update NY