Path: utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!cs.utexas.edu!usc!srhqla!tcm
From: tcm@srhqla.SR.COM (Tim Meighan)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Original IBM PC -- Don't laugh!
Keywords: RAM chips / 64kx1 / 4164
Message-ID: <1230@srhqla.SR.COM>
Date: 20 Dec 89 21:44:10 GMT
References: <1747@clyde.concordia.ca>
Reply-To: tcm@srhqla.SR.COM (Tim Meighan)
Organization: Silent Radio, Los Angeles
Lines: 39

In article <1747@clyde.concordia.ca> smw@maxwell.Concordia.CA
( Steven Winikoff ) writes:

>The chips are labelled as follows:
>
>	TMS 4164 - 15NLJ

>Questions:
>
>  1)  Am I right?

Quite so, these are 64K DRAMs with 150nS access time.

>  2)  If so, then this board will only hold another 64k worth of these
>      chips.  Can I replace them with larger chips?  Who does the 
>      address decoding -- ie will he need a different add-in board?

The original PC will NOT take 256K chips.  An add-on board would work.

>  3)  In general, what would you do in this situation?  

My honest answer?  Junk the motherboard, spend at least the $100 for a
Turbo-XT clone board that'll do 10Mhz clock speed.  Your friend is
truly wasting their time trying to upgrade an original PC board at
this point.  BTW, RAM is extra but fairly cheap.  It would cost more
to buy add-on boards, accelerator boards, etc, than to just get a
new mother board and some 256K DRAM chips and be done with it. 

Your friend might look at this as $100 for a case, power supply,
original-style layout PC keyboard, and whatever other boards were included.
If they got a monitor and monitor card, or a floppy drive and floppy
controller out of the deal, they probably got good value for the money. 

Your friend may want to consider leaving the PC as is for historical
reasons -- in 30 years an original IBM-PC may have collectable value.
(Now it's MY turn to say "don't laugh!")

Tim Meighan
SilentRadio