Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!mailrus!iuvax!pur-ee!pc.ecn.purdue.edu!wards
From: wards@pc.ecn.purdue.edu (Sherman Ward)
Newsgroups: comp.sys.mac
Subject: Re: Another Memory Question?
Keywords: Memory SIMMS MAC II
Message-ID: <1147@pc.ecn.purdue.edu>
Date: 13 Dec 88 19:19:21 GMT
References: <825@savax.UUCP> <74566@felix.UUCP>
Reply-To: wards@pc.ecn.purdue.edu.UUCP (Sherman Ward)
Organization: Purdue University Engineering Computer Network
Lines: 63

In article <74566@felix.UUCP> kehr@felix.UUCP (Shirley Kehr) writes:
>In article <825@savax.UUCP> michali@savax.UUCP (Paul C. Michali) writes:
><Someone had mentioned that memory on the PLUS and SE had to be done in pairs.
><Is this true for the Mac II?  Can one have 3MB ( four 256K and two 1M SIMMS)?
><PCM
>
>With a Mac II you have the option of buying it with 1Mbyte and adding 4
>256K chips to bring the total to 2 Mbytes. Or you can buy 4 1Mbyte SIMMs
>and bring the total to 5 Mbytes. Beyond that you throw away the original
>1 Mbyte and put in 4 more 1 Mbyte SIMMs for a total of 8 Mbytes.
>Most people I've talked to won't sell Mac II SIMMs (1Meg) two at a time
>because you have to do 4 at a time. Be sure the 2Mbyte SIMM package 
>is really for a Mac II, and get two of them.  You can also buy a 
>Mac II with 4 Mbytes (and a 40 Meg disk). . . . .
>Shirley Kehr

Am I understanding correctly that MacII (1Meg) SIMMs are different
than MacSE SIMMs (1Meg)??  (Speed differences only?? 150NS vs <150NS???)

I have been checking into what I can do with my 6 extra 256K
(150 NS) SIMMs that I pulled from Mac SEs.  To MY UNDERSTANDING
(please correct me and I'm certain somebody knows more than I do :-)
the MacSE is designed for use with 150NS (or faster) SIMMs,
whereas the MacII is designed for use (and shipped) with 120NS SIMMs.

Now, the MacSE has 4 SIMM slots.  Shipped with 4 256K (150NS) SIMMs
     (1Meg).  To go to a 2Meg or 2.5Meg you pull 2 of the 256's and
     replace with 1Meg SIMMs.  In order for the SE to understand
     the change in memory you (read "Authorized repair Persons" :-)
     need to clip off a resistor.  For a 4Meg upgrade, you jerk all
     4 of the 256's and replace with 1Meg SIMMs.  
And now you have 2 or 4 (150NS) 256K SIMMs which do not have a home :-(

The MacII has 8 SIMM slots.  The MacII (1Meg) has 4 slots filled
with 256K SIMMs (120NS).  Leaving 4 open slots.  I don't know the
complete details of installation, but I ASSUME (I know, A** out of
U & ME) to go to 2Meg just add 4 256K SIMMs (120NS), 5Meg add 4
1Meg (120NS or faster???) SIMMs (clip a resistor????), 8Meg pull
the 4 256's and replace with 1Meg SIMMs.

Questions:
  1) Is there a good (and easy) home for 256K (150NS) SIMMs??
     (In a Laserwriter+, LaserwriterNT, or an IBM AT class
      machine?) (I would hate to trash them).  

  2) Can I replace ALL 120NS SIMMs in a MacII and put in 150NS
     SIMMs in as replacements?? Any mechanical/technical problems
     using 150NS chips in a machine designed for 120NS Chips??
     (I realize thru-put would suffer but at least I could use 
      my 150NS 256's :-)

  3) Does a MacII puke with different speed 256's inside? 

  4) What is the slowest speed SIMM a MacSE or MacII will accept
     without technical difficulties??  I know that slower chips
     cost less $$$.

Later, Sherman
+-------------------------------------------------------------------+
-- 
+SNAIL: Sherman Ward / Freshman Engineering / Purdue University /   +
+       Rm 221 Engineering Admin. Bldg. / West Lafayette, IN  47907 +
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+ wards@pc.ecn.purdue.edu + (317) 494-3976 +  I believe in Murphy!  +