Xref: utzoo comp.sys.amiga:63401 comp.sys.amiga.hardware:2960
Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!uwm.edu!cs.utexas.edu!uunet!cbmvax!daveh
From: daveh@cbmvax.commodore.com (Dave Haynie)
Newsgroups: comp.sys.amiga,comp.sys.amiga.hardware
Subject: Re: Another A3000 RAM question
Message-ID: <13750@cbmvax.commodore.com>
Date: 10 Aug 90 15:21:28 GMT
References: <32628@cup.portal.com>
Reply-To: daveh@cbmvax (Dave Haynie)
Distribution: usa
Organization: Commodore, West Chester, PA
Lines: 50

In article <32628@cup.portal.com> davids@cup.portal.com (David Kenneth Schreiber) writes:
>I've got bank 0 filled with the DIPs that came with the machine;  in bank 1
>I've installed the ZIPs.  When I power up, Kickstart 2.0 loads, the machine 
>is reset, then I get a System Error #80000003 at location 07e03234 (well, 
>somewhere in the 07e03000's;  I believe 07e03234 is the correct address). Can
>anyone tell me what socket a bad ZIP would have to be in to cause an error
>at that address?  I've tried swapping chips around, but the same error
>always shows up at the same place.

With 256K x 4 chips, it takes 8 chips to make up one 1 megabyte, which is
of course organized as 256K x 32.  From your description, the only thing I
can tell is that something in the second bank of chips, the ZIPs you added,
may be amiss.  The A3000 memory builds down from $07ffffff as you add it.
The base machine comes with 1 Meg located in $07f00000-$07ffffff.  The next
bank is located from $07e00000-$07efffff.  All 8 chips go to make up that
bank, so a problem in any one of them will affect the entire 1 Meg chunk.
Before you panic too much, make absolutely sure that you're putting these
parts in the right sockets; the arrangement of sockets doesn't make much
sense to anyone who didn't have lay out the circuit board.

>The Mitsubish has one pin missing, though (the technical support person at 
>Krueger said this was not a problem, that some ZIPs are just made that way;
>is he right?).

Yes, that's correct.  The 256K x 4 parts have one unused pin, some makers 
provide a useless pin there, others leave the pin off.  That pin is the
extra address pin for the 1 Meg x 4 parts.

>P.S.  Kickstart/Workbench 1.3 loads fine, and Memtest V2.0 reports no
>errors.

Ah, so.  Check the parts your machine came with; the DRAM in the first bank.
If these read something like "44258" rather than "44256", you have a known
problem.  The A3000's memory controller, the RAMSEY chip, has a special
memory mode for support of SCRAM (Static Column DRAMs) memories to support
burst mode.  This special memory mode, however, has the unfortunate effect
of confusing the hell out of normal page-mode memories.  If there are any
page-mode memories in system, even just one, the static column mode must
be disabled for the entire Fast memory system.  This detection has to be
done in software.  The A3000's version of 1.3 doesn't bother with trying to
determine this, it simply leaves the SCRAM modes off.  Under the current
2.0, they are doing some kind of SCRAM check, but it's not very robust.  So
SCRAM memories in the first bank will cause the SCRAM mode to be set, no
matter what's in the latter Fast memory banks.  And I have heard that some
A3000s are now going out with the faster SCRAMs in the first DIP bank.  So
my guess is that you have SCRAMs in your first 1-meg bank.
-- 
Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests"
   {uunet|pyramid|rutgers}!cbmvax!daveh      PLINK: hazy     BIX: hazy
      Get that coffee outta my face, put a Margarita in its place!