A photo of the display on an old Toshiba 205CDS is here.
formatting link
An external monitor connected to the machine is illustrated here.
formatting link
From that I conclude the problem is in the video adapter rather than the laptop screen or monitor.
This is approximately how the display should appear.
formatting link
Testing the video adapter isn't as easy as swapping a card in a desktop machine. Any ideas for a repair?
Thanks, ... Peter E.