The maximum resolution on the DOS compatible card is 800x600 with 16 colors. In order to use this resolution, the sense pin configuration must match that of an Apple 16 inch monitor on the Macintosh side. The problem is the video on the DOS compatible card is set up at boot time, and cannot be changed until a reboot. If the sense pins are configured for, say, an Apple 14 inch and then the resolution is changed through software, the graphics chip on the DOS compatible card is in an undetermined state. This will keep it from outputting a recognizable signal, so no video is displayed.
The work around is to configure the sense pins on the monitor for a Apple 16 inch monitor. This will allow the Macintosh to set the correct video parameters on boot, to be sent to the DOS compatible card. There are two vendors that we know of that sell adapters that will allow you to configure the sense pins on the monitor. The vendor names are: James Engineering and Enhance Cable Technology. To locate a vendor's address and phone number, use the vendor name as a search string.
Once you have attached the proper cable adapter which sets the sense pins for a 16 inch display, the DOS compatible card will support the same resolutions which are supported for a 16 inch attached monitor, which is outlined in the TIL article: "DOS Card: Video Modes Supported".
Note: Once you configure the sense pins for an Apple 16 inch Color Display, unless the Mitsubishi comes with special software, you won't be able to switch resolutions while the computer is running on the Macintosh side.
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