Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!cs.utexas.edu!sdd.hp.com!zaphod.mps.ohio-state.edu!wuarchive!texbell!merch!cpe!techsup!garyk
From: garyk@techsup.UUCP
Newsgroups: comp.sys.tandy
Subject: Re: Tandy 1000 memory upgrade
Message-ID: <15400021@techsup>
Date: 1 May 90 15:49:00 GMT
References: <4989@hub.ucsb.edu>
Lines: 26
Nf-ID: #R:hub.ucsb.edu:4989:techsup:15400021:000:1359
Nf-From: techsup.UUCP!garyk    May  1 09:49:00 1990


/* Written 9:34 am Apr 30, 1990 by hub.ucsb.edu!crmeyer in comp.sys.tandy */
/* ---------- "Tandy 1000 memory upgrade" ---------- */
I am attempting to help a friend upgrade her original Tandy 1000 (25-1000)
from 512K to 640K of RAM. The computer currently has a 256K Memory expansion
board fully populated (25-1004) and a 512K memory expansion board with
two rows unpopulated (25-1009). The 256K board has E2 jumpered to E1 and
the 512K board has E4 jumpered to E3. What type of memory chips do I
need to upgrade the computer (4164-200ns or faster?). What should I change
the jumpers on the memory board(s) to?
                      +-----------------------------------+                    
                      |         Charles R. Meyer          |                    
                      +-----------------------------------+                    
/* End of text from techsup:comp.sys.tandy */
All boards require 64kx1 150ns RAM.

25-1004  No Jumpers -> 1st board with 128k installed & DMA  system = 256k
	 E1-E2      -> 1st board with 256k installed & DMA  system = 384k

25-1009  E3-E4      -> 2nd board with 128k installed        system = 512k 
	 E1-E2 E3-E4-> 1st board with 256k installed        system = 640k

The first board must be installed and fully populated before the 2nd board
is installed.
			Gary k
			{texbell:sys1:trsvax}!techsup!garyk