Path: utzoo!attcan!uunet!munnari.oz.au!uhccux!uhunix1.uhcc.Hawaii.Edu!robin
From: robin@uhunix1.uhcc.Hawaii.Edu (Robin Amano)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: DIP switches in original PC
Message-ID: <9976@uhccux.uhcc.Hawaii.Edu>
Date: 22 Oct 90 19:13:53 GMT
References: <1370@beguine.UUCP>
Sender: news@uhccux.uhcc.Hawaii.Edu
Organization: University of Hawaii
Lines: 74

In article <1370@beguine.UUCP> Robert.Berry@samba.acs.unc.edu (Robert Berry) writes:
>I've been working with an old IBM PC (the original--2 floppies, monochrome
>monitor, 256K memory, etc.) at work and I want to make sure the DIP
>switches on the motherboard are set correctly.  I have no hardware
>documentation, so can anyone tell me what the switches on each of the
>two switch blocks on the original PC motherboard designate?  The only
>ones I'm sure of are 5 and 6 on switch block 1, which set the video
>adapter type.  I have no idea what the second switch block is for at all.

When upgrading to 640K look at the back of case should either have the letter
A or B in a circle.  If B you can upgrade, if A you need to have ROM replaced.

SW1                                             ON          OFF

Number of 5 1/4" Drives
    0                                           1,7,8    
    1                                           7,8         1
    2                                           8           1,7

Math Coprocessor Installed                      2
Math Coprocessor Not Installed                              2

RAM Memory Installed on System Board
    64K - 256K System Board                                 3,4
    16K - 64K System Board
      16K                                       3,4
      32K                                       4           3
      48K                                       3           4
      64K                                                   3,4

Monitor Adapter Installed           
      None                                      5,6
      Monochrome Monitor/Printer Adapter                    5,6
      Color Graphics Monitor Adapter            6           5
          (40 X 25 Color)
      Color Graphics Monitor Adapter            5           6
          (80 X 25 Color)  


SW2                                             ON          OFF

Note:  Switches 6, 7, and 8 are always OFF.

16K - 64K System Board
      16K - 64K (on Main Board)                 1,2,3,4,5
      96K   					2,3,4,5     1
      128K					1,3,4,5     2	
      160K					3,4,5       1,2
      192K					1,2,4,5     3
      224K					2,4,5	    1,3
      320K					1,2,3,5     4
      352K					2,3,5	    1,4
      384K					1,3,5       2,4
      416K					3,5         1,2,4
      448K					1,2,5       3,4
      480K					2,5	    1,3,4
      512K					1,5         2,3,4
      544K					5	    1,2,3,4
      576K					1,2,3,4     5
      608K					2,3,4	    1,5
      640K 					1,3,4       2,5

64K - 256K System Board
      64K					1,2,3,4,5
      128K					same as above

Hope this helps.

	
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