Computers (fwd) - test-drb@ccmp.vtda.org

21 Aug 1997

...
  Hi there.  I noticed in your collection that you had
an IBM PC; I'm
 assuming it's a 5150.  Do you have a manual for it that might list the
 jumper and dip switch settings on the motherboard, and if so, could you
 tell me what they are?  Thanks. 
The 5150 (i.e. the PC) has 2 switchblocks on the motherboard. The one
nearest the power supply Block 2) controls the amount of memory addressed:

Mem	Switch number
(KB)	1   2   3   4   5   6   7   8
-------------------------------------
 16	1   1   1   1   1   0   0   0
 32	1   1   1   1   1   0   0   0
 48	1   1   1   1   1   0   0   0
 64	1   1   1   1   1   0   0   0
 96	0   1   1   1   1   0   0   0
128	1   0   1   1   1   0   0   0
160	0   0   1   1   1   0   0   0
192	1   1   0   1   1   0   0   0
224	0   1   0   1   1   0   0   0
256	1   0   0   1   1   0   0   0
288	0   0   0   1   1   0   0   0
320	1   1   1   0   1   0   0   0
352	0   1   1   0   1   0   0   0
384	1   0   1   0   1   0   0   0
416	0   0   1   0   1   0   0   0
448	1   1   0   0   1   0   0   0
480	0   1   0   0   1   0   0   0
512	1   0   0   0   1   0   0   0
544	0   0   0   0   1   0   0   0
576	1   1   1   1   0   0   0   0
608	0   1   1   1   0   0   0   0
640	1   0   1   1   0   0   0   0

0=Off
1=On

Switch block 1 is farther from the power supply

Switch 1 -- 
	PC -- 0=Boot from Floppy
		1=Do not boot from floppy
	XT -- 0=Normal POST (power On Self Test)
		1=Continuous POST (i.e., won't boot)

Switch 2 -- 	0=Math coprocessor installed
		1=Math coprocessor not installed

Switches 3-4 -- Filled memory banks (on motherboard)
	0 0 =All 4 banks
	1 0 = Banks 0, 1, and 2
	0 1 = Banks 0 and 1
	1 1 = Bank 0 only

Switches 5-6 -- Video Adapter
	0 0 = Monochrome (MDA) or Hercules with no onboard BIOS
	0 1 = Color (CGA) 40 chars x 25 lines
	1 0 = CGA 80 chars x 25 lines
	1 1 = Video Adapter w/ onboard BIOS

Note that the PC will support a monochrome adapter at the same time as
another type.

Switches 7-8 -- Floppy Drives
	1 1 = 1 Floppy Drive
	0 1 = 2 FDD
	1 0 = 3 FDD
	0 0 = 4 FDD

Hard drive is taken care of by the adapter card.

Please e-mail me with any other questions.

manney(a)nwohio.com