[comp.sys.mac.hardware] Missing IIsi ROM SIMM ???

bin@primate.wisc.edu (Brain in Neutral) (12/22/90)

Well, I'll freely confess to not having any knowledge of hardware, but...

I just installed 4MB memory in two Macintosh IIsi's, which were
ordered in identical configuration but which arrived about 3 weeks
apart.  (Memory was from Chip Merchant, by the way.  Installation
was a snap.  Memory worked perfectly).

I noticed that the second machine didn't have the card installed that
sits next to the RAM SIMM slots.  "Odd, I thought.  What is it?" and
peered closer to the circuit board.  It says "ROM SIMM" by the card
bay.

So I have two "identical" machines, except that one is apparently
missing its ROM!  But it works...

What's the deal?

-- 
Paul DuBois
dubois@primate.wisc.edu

kanefsky@cs.umn.edu (Steve Kanefsky) (12/22/90)

In article <3624@uakari.primate.wisc.edu> bin@primate.wisc.edu (Brain in Neutral) writes:
>Well, I'll freely confess to not having any knowledge of hardware, but...
>
>I just installed 4MB memory in two Macintosh IIsi's, which were
>ordered in identical configuration but which arrived about 3 weeks
>apart.  (Memory was from Chip Merchant, by the way.  Installation
>was a snap.  Memory worked perfectly).
>
>I noticed that the second machine didn't have the card installed that
>sits next to the RAM SIMM slots.  "Odd, I thought.  What is it?" and
>peered closer to the circuit board.  It says "ROM SIMM" by the card
>bay.
>
>So I have two "identical" machines, except that one is apparently
>missing its ROM!  But it works...
>
>What's the deal?

The ROM SIMM slot was intended for ROM *upgrades*.  The ROM included with
newer IIsi's is soldered onto the motherboard (to save on manufacturing costs).

Apple did mention that some of the first IIsi and LC Macs may have the ROM
on SIMMS instead of soldered in. 

It shouldn't make any difference at all in terms of performance or 
upgradability whether your ROMs are soldered-on or on SIMMS.  It just saves
apple a few $$$ to mass-produce mother boards with the ROM soldered-on.


-- 
Steve Kanefsky             
kanefsky@cs.umn.edu 

marc@Apple.COM (Mark Dawson) (12/22/90)

In article <3624@uakari.primate.wisc.edu> bin@primate.wisc.edu (Brain in Neutral) writes:
>Well, I'll freely confess to not having any knowledge of hardware, but...
>
>I just installed 4MB memory in two Macintosh IIsi's, which were
>ordered in identical configuration but which arrived about 3 weeks
>apart.  (Memory was from Chip Merchant, by the way.  Installation
>was a snap.  Memory worked perfectly).
>
>I noticed that the second machine didn't have the card installed that
>sits next to the RAM SIMM slots.  "Odd, I thought.  What is it?" and
>peered closer to the circuit board.  It says "ROM SIMM" by the card
>bay.
>
>So I have two "identical" machines, except that one is apparently
>missing its ROM!  But it works...
>
>What's the deal?
>
Probably means they finally got the ROMs that they put on the logic board
in production (the ROM SIMMs are more expensive).

Mark


-- 
---------------------------------
Mark Dawson                Service Diagnostic Engineering
AppleLink: Dawson.M

Apple says what it says; I say what I say.  We're different
---------------------------------

granteri@pnet51.orb.mn.org (Grant Erickson) (12/25/90)

bin@primate.wisc.edu (Brain in Neutral) writes:
>I noticed that the second machine didn't have the card installed that
>sits next to the RAM SIMM slots.  "Odd, I thought.  What is it?" and
>peered closer to the circuit board.  It says "ROM SIMM" by the card
>bay.
>
>So I have two "identical" machines, except that one is apparently
>missing its ROM!  But it works...
>
>What's the deal?
>
>-- 
As I believe it to be, some of the first IIsi's were shipped with the ROMs
soldered to the mother board. Peering inside mine I have a ROM SIMM. However,
a friend who bought his on Oct. 16 is lacking the afformentioned SIMM. Someone
please feel free to correct and flame me if this infomation is erroneous.
>Paul DuBois
>dubois@primate.wisc.edu

Grant Erickson

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