billdeg
Technician
To add a comment, the picture below shows where to plug the internal monitor cable to the stock CGA card; if you remove this connection then you'll only have external monitor capability.
larger pictures of my system related to CGA internal monitor cabling here:
http://vintagecomputer.net/ibm/5155/ibm5155_monitor_connector_cga_card.jpg
http://vintagecomputer.net/ibm/5155/ibm5155_color-graphics_controller.jpg
Bill
larger pictures of my system related to CGA internal monitor cabling here:
http://vintagecomputer.net/ibm/5155/ibm5155_monitor_connector_cga_card.jpg
http://vintagecomputer.net/ibm/5155/ibm5155_color-graphics_controller.jpg
Bill