BACK

The Original PC

Motherboard DIP Switch Settings



This article was found at COMPUTER CRAFT. We feel bad about stealing, but we also feel that articles like this should be more widely available.

The PC (5 expansion slots and 65W power supply) had two banks of eight DIP switches:

BANK ONE

SWITCHES 1, 7, and 8 indicate the number of floppy drives:
1,7, and 8 ON - ZERO drives
1, OFF, 7 and 8 ON - ONE drive
1 and 7 ON, 8 OFF - TWO drives
1 and 8 OFF, 7 ON - THREE drives
1, 7, and 8 OFF - FOUR drives

Switch 2: NOT USED - MUST BE ON

Switches 3 and 4 indicate the amount of memory on the system board:
For 16K - 3 and 4 ON
For 32K - 3 OFF, 4 ON
For 48K - 3 ON, 4 OFF
For 64K to 256K (or greater) - 3 and 4 OFF

Switches 5 and 6 indicate the display:

5 and 6 ON - NO display
5 OFF, 6 ON - COLOR (CGA 40 X 25)
5 ON, 6 OFF - COLOR (CGA 80 X 25)
5 and 6 OOFF - Monochrome (or more than one display adapter)

BANK TWO

switches 1, 2, 3, 4, and 5 indicate memory options
switches 1, 2, 3, 4, and 5 ON - 16K to 64K
switches 1, 3, 4, and 5 ON, 2 OFF - 128K
switches 1, 2, 4, and 5 ON, 3 OFF - 192K
switches 1, 4, and 5 ON, 2 and 3 OFF - 256K (or greater)

switches 6, 7, and 8 NOT USED - MUST BE OFF

NOTE: For both the PC and the XT (including clones), the DIP switches on the motherboard have NOTHING to do with installing a hard drive! The hard drive is controlled by the BIOS on the hard drive adapter card. There will very likely be switches and/or jumpers on the adapter card that will need to be set for different hard drives.


BACK