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From: daver@ux1.cso.uiuc.edu
Newsgroups: comp.sys.ibm.pc.misc
Subject: ram chips, motherboards, what fun!
Message-ID: <17100064@ux1.cso.uiuc.edu>
Date: 17 Jul 90 20:08:00 GMT
Lines: 25
Nf-ID: #N:ux1.cso.uiuc.edu:17100064:000:1475
Nf-From: ux1.cso.uiuc.edu!daver    Jul 17 15:08:00 1990


I bought a used XT several months ago and decided to learn about
it's insides the hard way.  I bought a 12 mhz mother board thinking
I could just take my old one out and put my new one in.  This is mostly
true except that I found out that they don't use the same ram chips.
The old one has one row of 256x1 chips, the new one requires 2 256x4
and 1 256x1.  So I bought a set of 100ns chips and figured, hey, I've
got 256k, but the dip switch on the board only started at 512.  I went out
and bought the second set.
Here lies my problem. 
I also have an i/o board with memory.  It has 384k in 64k chips.  I figured
that I could use it with 256k on the new mb and have 640.  With the minimum
at 512, I hoped that it would ignore that extra 256 on the card.  It started
to work.  The ram check at the start up gets to 624 and says "parity error"
I figure I have more ram than it is expecting, or it doesn't like 64k chips.
So, I could just take off a bunch of 64k chips ( i need the i/o part 
of the board at the moment), but there are these 6 dip switches on the board
that I assume tell it how much ram is there.
Anybody know how to tell what brand of i/o-memory card I have?  
Anybody have an idea what switches to flip?  (is it safe to experiment?)
And while I'm at it, how do I tell how fast the chips are?  
Thanks
----------
David Ruby                                  University of Illinois  
"This calls for a special blend of psychology and extreme violence" vyvyan