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From: ephraim@think.com (Ephraim Vishniac)
Newsgroups: comp.sys.mac.hardware
Subject: Re: Classic MacII ROM incompatibilities?
Message-ID: <41402@think.Think.COM>
Date: 10 Aug 90 14:35:22 GMT
References: <1337@s5.Morgan.COM>
Sender: news@Think.COM
Reply-To: ephraim@leander.think.com.UUCP (Ephraim Vishniac)
Organization: Thinking Machines Corporation, Cambridge MA, USA
Lines: 50

In article <1337@s5.Morgan.COM> jordan@Morgan.COM (Jordan Hayes) writes:
>Anyway, someone from Radius
>mentioned that on the old MacII ROMs, there was an incompatibility with
>large monitors (specifically, he said, NuBus cards that address more
>than 1 Mb of memory).  I've called *every* Apple Authorized Dealer in
>Manhattan, and they *all* are idiots!  No one even knows what a ROM is?!?.

Here's the answer, straight from the Apple's mouth:

From: kateley@Apple.COM (Jim Kateley)
Newsgroups: comp.sys.mac.hardware
Subject: Re: Summary: PMMUs vs Mac IIs -- which ones don't work
Date: 10 Feb 90 21:11:16 GMT
Organization: Apple Computer, Metro Plaza, San Jose CA
Lines: 33

In article <3092@pur-phy> sho@maxwell.physics.purdue.edu.UUCP (Sho Kuwamoto) writes:
>You machine will be affected if you have Rev. A ROMs.  They moved
>to Rev. B ROMs sometime around February 1988.

Actually, there are two seperate repair extenstion programs for the Macintosh
II. 

The first, announced in Feburary of 1988, addresses a ROM glitch where
NuBus cards with more than 1MB of address space cannot be accessed.  This is
the "Rev A to Rev B" program.  Your dealer can see page 8.4.13 of their service
programs binder for details. 

The other, announced in August of 1989, is for the HMMU/PMMU socket situation
where the socket for the PMMU on some units does not have all the necessary
pins for a PMMU to function (although it does have enough pins for the HMMU).
Your dealer can see page 8.4.14 of their service programs binder for details.

In the first case, you would have a problem if you had a NuBus card that
required more than 1MB of address space.  In the second case, your MacII
would not work if you installed a PMMU.

Both situations require a main logic board swap, which is at no cost to you.
-- 
Jim Kateley          UUCP: {sun, voder, nsc, mtxinu, dual}!apple!kateley
S,P,HnS!             DOMAIN: kateley@apple.COM  Applelink: kateley1
Disclaimer:   What I say, think, or smell does not reflect any policy or
	      stray thought by Apple Computer, Inc.


--
Ephraim Vishniac    ephraim@think.com   ThinkingCorp@applelink.apple.com
 Thinking Machines Corporation / 245 First Street / Cambridge, MA 02142
        One of the flaws in the anarchic bopper society was
        the ease with which such crazed rumors could spread.