Switch # Function Settings 1 Test On = loops on POST, Off = normal operation 2 Coprocessor On = yes, Off = no 3 & 4 System board RAM On On = 64K Off On = 128K On Off = 192K Off Off = 256K 74ls158 U84 + 9 64k's in bank 3 & 4 = 640K Instructions (Bios Chip should say 1986) 27256-1 For 640K U18 P/N 59X7268 U19 P/N 62X0819 Jumper on E2 5 & 6 Display adapter On On = no adaptor Off On = CGA 40 columns On Off = CGA 80 columns (VGA Settings) Off Off = MDA or more than one adapter 7 & 8 Floppy drives On On = 1 Off On = 2 On Off = 3 Off Off = 4 ...or mebbe not.