[comp.sys.mac] MAC 256K SIMMs --> Mac ][ HELP

jasst3@cisunx.UUCP (Jeffrey A. Sullivan) (11/09/87)

I have a question regarding the 256K SIMMs in the Mac SE.  I have an SE and
am about to have 2 1M SIMMs put into it tyo boost my RAM to 2.5M.  I am also
planning (in the relatively near future) to sell the SE and get a Mac ][.  My
Question is this:  Can I just slip those 2 256K SImms into the second bank
of the ]['s memory banks (along with another pair of 256K SIMMs) and have
an extra meg?  Are the speeds of the chips OK?

Also, is it possible to un-do a 2M expansion to an SE so I could use the 2
1M SIMMs in the ][ and put the 256K SIMMs back in the SE?

This raises another question:  What are the allowable increments for adding
SIMMs to a Mac ][?  Can I pop in 1M SIMMs 1 at a time to bump my memory up
by 1 Meg increments?  What does the ][ come with: 4 256K SIMMs?

Thanks for any help provided.

..........................................................................
Jeff Sullivan				University of Pittsburgh
pitt!cisunx!jasst3			Intelligent Systems Studies Program
jasper@PittVMS (BITNET)			Graduate Student
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

kwallich@hpsmtc1.HP.COM (Ken Wallich) (11/10/87)

jasst3@cisunx.UUCP (Jeffrey A. Sullivan) / 11:07 am  Nov  9, 1987 /

>Question is this:  Can I just slip those 2 256K SImms into the second bank
>of the ]['s memory banks (along with another pair of 256K SIMMs) and have
>an extra meg?  Are the speeds of the chips OK?

The Mac II comes with 120ms chips.  The SE comes with 150ms chips.
The Mac II will run with ALL 120ms chips, or ALL 150ms chips, but if you 
combine the two, it will only recognize the faster (120ms) chips.  You could
put 120ms chips in your SE, but I don't know how well this works (I have a
MacII :-).  Also I assume you mean 4 256K SIMMs to make a Meg.  Even though
they sell them in 2's, 1 SIMM is either 256K or 1MB depending on the chips.

>Also, is it possible to un-do a 2M expansion to an SE so I could use the 2
>1M SIMMs in the ][ and put the 256K SIMMs back in the SE?

The same chip speeds apply to the 1MB chips.  See the previous caviats,
or is that caviar?

>This raises another question:  What are the allowable increments for adding
>SIMMs to a Mac ][?  Can I pop in 1M SIMMs 1 at a time to bump my memory up
>by 1 Meg increments?  What does the ][ come with: 4 256K SIMMs?

The II (][ reminds me of a *gag* Apple ][) does indeed come with 4 256K SIMMs
unless you order it with more, in which case the dealer will insall the 
upgrade, and keep the 256K chips for someone else (be carefull not to pay for 
them!).  You cannot "pop" 1MB SIMMs 1 at a time :-(.  There are 2 "banks"
of memory, and each must be fully populated (4 SIMMs) with the same density
chips.  In multiple density configurations, the highest density chips must
be in the lowest bank (bank "A").

Possible memory configurations are as follows (this is reposted from something
someone else posted a month or two ago, sorry I don't remember who):

RAM         Bank A                  Bank B               What To Order
-----       -------                 -------              -------------
1M          Four 256K SIMMs         Empty                Factory Standard
2M          Four 256K SIMMs         Four 256K SIMMs      1 - MO218
4M          Four  1M  SIMMs         Empty                2 - MO219
5M          Four  1M  SIMMs         Four 256K SIMMs      2 - MO219
8M          Four  1M  SIMMs         Four  1M  SIMMs      4 - MO219

Where:
  MO218 - 4 256K SIMMs 
  MO219 - 2 1Mb  SIMMS 

----------

Hope this helps you out!


--------------------
Ken Wallich			*My views are mine, and mine alone*
Consultant			"Camelot! Camelot! -- It's only a model"	
DCI 				kwallich@hpsmtc1.HP.COM
@Hewlett Packard		...hplabs!hpsmtc1!kwallich

"Your Delta Tou Kai name is ... Flounder" 

drc@dbase.UUCP (Dennis Cohen) (11/11/87)

In article <5134@cisunx.UUCP>, jasst3@cisunx.UUCP (Jeffrey A. Sullivan) writes:
> I have a question regarding the 256K SIMMs in the Mac SE.  I have an SE and
> am about to have 2 1M SIMMs put into it tyo boost my RAM to 2.5M.  I am also
> planning (in the relatively near future) to sell the SE and get a Mac ][.  My
> Question is this:  Can I just slip those 2 256K SImms into the second bank
> of the ]['s memory banks (along with another pair of 256K SIMMs) and have
> an extra meg?  Are the speeds of the chips OK?
No, you cannot just plug those two in, you'll need two more as well.  The Mac II
requires memory expansions in groups of four (4) SIMMs.  If the chips are 120nS
you'll be ok on speed.

> 
> Also, is it possible to un-do a 2M expansion to an SE so I could use the 2
> 1M SIMMs in the ][ and put the 256K SIMMs back in the SE?
Yes, it's possible to undo the expansion to the SE, but you'll still need four
SIMMs for the Mac II, so the 2 1MB SIMMs are only useful in the SE (or a Plus)
in that quantity.

> 
> This raises another question:  What are the allowable increments for adding
> SIMMs to a Mac ][?  Can I pop in 1M SIMMs 1 at a time to bump my memory up
> by 1 Meg increments?  What does the ][ come with: 4 256K SIMMs?
The allowable configurations for the Mac II are:
	1 MB:	4 256KB SIMMs in the four slots closest to the right side (facing)
	2 MB:	8 256KB SIMMs
	4 MB:	4 1MB SIMMs in the four slots closest to the right side
	5 MB:	4 1MB SIMMs in the four rightmost slots & 4 256KB SIMMs in the other four slots
	8 MB:	8 1MB SIMMs


Dennis Cohen
Ashton-Tate Glendale Development Center
dBASE Mac Development Team
--------------------------
(Standard disclaimer applies)

ir353@sdcc6.ucsd.EDU (Matthew Grayson) (11/11/87)

In article <11540041@hpsmtc1.HP.COM> kwallich@hpsmtc1.HP.COM (Ken Wallich) writes:
>The Mac II comes with 120ms chips.  The SE comes with 150ms chips.
>The Mac II will run with ALL 120ms chips, or ALL 150ms chips, but if you 
>combine the two, it will only recognize the faster (120ms) chips. 

Shhhhh! My Mac II might hear you. Perhaps the faster chips just have
to be farther from the processor? I've had no troubles since I
bought 1 meg of used 150ns SIMMs to upgrade to 2 meg. $180 for 2meg
seemed a better idea than $1000 for 5. Unfortunately, running
TeXtures with LaTeX under multifinder leaves me 36K available.
sigh....
	Matt

isle@dartvax.UUCP (Ken Hancock) (11/11/87)

In article <5134@cisunx.UUCP> jasst3@cisunx.UUCP (Jeffrey A. Sullivan) writes:
>Question is this:  Can I just slip those 2 256K SImms into the second bank
>of the ]['s memory banks (along with another pair of 256K SIMMs) and have
>an extra meg?  Are the speeds of the chips OK?
>
>Also, is it possible to un-do a 2M expansion to an SE so I could use the 2
>1M SIMMs in the ][ and put the 256K SIMMs back in the SE?

First question.  The SE uses 150 nanosecond 256K SIMMs.  (-15 on the chip).
120 nanosecond chips should be used on the Mac II.  (-12).  I have heard
of people who have put in 150's...I don't know what the effect is...probably
slower memory.  (Anyone from Apple care to clarify this?)

Second Question.  It should be reversable as long as you have the -12 1MB
SIMMs.  I believe that a resistor should have also been removed when the
2 1MB SIMMs were swapped for the 256K SIMMs, so that would also have to
be replaces.

Ken

-- 
Ken Hancock      UUCP: isle@dartvax
               BITNET: isle@u2.dartmouth.edu

DISCLAIMER: If people weren't so sue-happy, I wouldn't need one!

david@wiley.UUCP (David Hull) (11/13/87)

In article <5134@cisunx.UUCP> jasst3@cisunx.UUCP (Jeffrey A. Sullivan) writes:
>Also, is it possible to un-do a 2M expansion to an SE so I could use the 2
>1M SIMMs in the ][ and put the 256K SIMMs back in the SE?

To expand the memory in an SE to more than the original 1 megabyte, you
have to cut a resistor out (my guess is that this resistor sets the
starting address of the second bank of memory).  If you cut through
only one of the leads to the resistor, you might be able to undo the
upgrade if you blobbed some solder on the cut, but it would be ugly.

The resistor is near SIMM #1, and is labeled "256K."  The 1M SIMMS go
in the slots labeled "SIMM 1" and "SIMM 2."

You should use 120ns SIMMS in your Mac II.  Chip tolerances being what
they are, you can probably get away with 150ns SIMMS, but I wouldn't
recommend it.  The Mac SE will use either kind with no problem.
I think that most upgrades sold today are 120ns SIMMS, though.  The
Apple upgrade is.  Check before ordering.

-David
					---------------------------------------
					David Hull  TRW Inc.  Redondo Beach, CA
					  ...!{uunet,cit-vax,trwrb}!wiley!david

dgold@apple.UUCP (David Goldsmith) (11/13/87)

In article <11540041@hpsmtc1.HP.COM> kwallich@hpsmtc1.HP.COM (Ken Wallich) writes:
>The Mac II comes with 120ms chips.  The SE comes with 150ms chips.
>The Mac II will run with ALL 120ms chips, or ALL 150ms chips, but if you 
>combine the two, it will only recognize the faster (120ms) chips.  You could
>put 120ms chips in your SE, but I don't know how well this works (I have a
>MacII :-).  Also I assume you mean 4 256K SIMMs to make a Meg.  Even though
>they sell them in 2's, 1 SIMM is either 256K or 1MB depending on the chips.

You CANNOT use 150ns SIMMs in the Macintosh II AT ALL, under ANY conditions.
The Mac II only works with 120ns RAM.  It has nothing to do with mixing 120ns
with 150ns; only 120ns RAM is fast enough.  Some people may succeed in using
150ns RAM because the parts they are using exceed spec and are in fact fast
enough, but there is no guarantee that will work -- you may experience
intermittent errors.  Repeat:  use ONLY 120ns RAM in the Mac II.

The Mac SE will work fine with either 150ns RAM, 120ns RAM, or any mixture of
the two.
-- 
David Goldsmith
Apple Computer, Inc.

AppleLink: GOLDSMITH1
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