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From: miles@cc.usu.edu (Miles Johnson)
Newsgroups: comp.sys.amiga.hardware
Subject: A1000 Internal mem hack questions.
Message-ID: <1990Nov16.154751.42580@cc.usu.edu>
Date: 16 Nov 90 21:47:51 GMT
Organization: Utah State University
Lines: 60


   Help me Mr Wizard!!!

   Three questions regarding the Chris Erving A1000 memory hack, with Dave
Haynie's autoconfig mods.  Chris's hack tells you how to piggyback 512k of
ram chips onto the top of the 256k of ram on an A1000 daughter board.  Dave's
addition will make the additional memory autoconfig.  The end result is
supposed to be a 1 meg A1000.

As I received Dave's notes they were labeled:

	How to Make Your PiggyBack RAM Expansion Auto-Configuring
			(c) 1986 by Dave Haynie

   I realize that this is pretty old.  It took me 4 years to nerve myself up
to doing it to my Amiga.  Now I need to debug it.  Hope you guys can clear up
a couple of lingering questions.  On power-up my 1000 shows gray, then green,
pause, gray, then green, pause, gray, green, red...  I think it means BAD
RAM,  don't know why it does it more than once.  The red should be bad ROM
checksum.  That doesn't make sense.  I figure I fried a ram chip somewhere.

   Before I jump in to replacing ram chips, I would like to clear up a couple
of points regarding Dave's instructions:

   1) Dave said:
>	Now you'll be dealing exclusively with the daughter board.  The
>daughter board I speak of is a 4-layer PCB labeled REV 3 on the back, up

      My daughter board was REV A.  Am I dead in the water?  Or just dead
      in the brain...

   2) Dave said:
>Next, find the 74F02 chip, called U5M on the PCB.  This chip is up 1 and
>slightly to the left of the DPALEN PAL.  **Cut pins 10, 11, and 12** away
>and up from the PCB as before.                      ^^  ^^      ^^
			.
			.
>	Now all that's left is interconnects.  Connect **freed pin 13** of
>the 'F02 to pin 11 of the 'F10.  Now connect pin 6 of the 'F10 to pin

      I didn't cut pin 13 of the 'F02 free of the motherboard.  It didn't
      say to cut it.  Was I supposed to?

   3) Dave said:
> ... The only pin that shouldn't be connected is pin 6 of the
>'F08, which doesn't go anywhere, as that part of the 'F08 isn't being used
>anywhere.

      I also had pin 12 of the 'F10 free.  It was never mentioned.

   I realize this is ancient history for you guys.  I would appreciate any
help you can offer.

Miles
-- 
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