Toshiba Satellite L20 Series Maintenance Manual page 110

NOTE: The following screen does not display correctly. It will be
amended in the next version.
Press [Enter] Key
Press Enter to execute the VRAM mapping test which displays a vertical line
at four dot intervals using Mode 12.
Press [Enter] Key
Press Enter to display VRAM mapping test using the all dots Mode.
110
Test Program for Field.
Satellite L20 Maintenance Manual(960-Q01)