Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!jason
From: jason@cs.utexas.edu (Jason Levitt)
Newsgroups: comp.sys.mac.hardware
Subject: 68851 PMMU STOMPS on Macintosh II
Keywords: 68851, Mac II, hardware, ?.
Message-ID: <1076@gort.cs.utexas.edu>
Date: 15 Jan 90 21:25:33 GMT
Organization: U. Texas CS Dept., Austin, Texas
Lines: 31


  I'm trying to put a 68851 PMMU chip in to a Macintosh II.
When I put the chip in, the machine will not boot.

  The chip is an early mask version denoted by "XC". It reads:

     XC68851RC16
     9B87D8724

  In addition, I believe the Macintosh II logic board is quite
early because there are 12 little chips just south of the NUBUS
slots, rather than one LSI chip. Is this correct?

   Is the problem with the early logic board version, or the
early PMMU mask, or both? 

   Does anyone know the serial #'s of bad logic boards, or mask
#'s of bad PMMU chips?

   Will Motorola or Apple let you trade in the bad chips or boards?

   I'll summarize answers to the net....

     ---Jason
-----

Jason Levitt    P.O. Box 49860  Austin, Texas 78765  (512) 459-0055
Internet: jason@cs.utexas.edu         | "Disneyland exemplifies the essence of
UUCP    : cs.utexas.edu!hackbox!jason |  the American spirit and continues to
BIX     : jlevitt                     |  show us the way to follow our dreams."
                                      |             -Ronald Reagan [1990]