Path: utzoo!attcan!uunet!lll-winken!ames!elroy!cit-vax!rodan.caltech.edu!childs
From: childs@rodan.caltech.edu
Newsgroups: comp.sys.amiga.tech
Subject: My Lucas Board
Message-ID: <9220@cit-vax.Caltech.Edu>
Date: 23 Jan 89 17:01:01 GMT
Sender: news@cit-vax.Caltech.Edu
Reply-To: childs@rodan.caltech.edu ()
Organization: California Institute of Technology
Lines: 43

Hi everyone,

I just finished building my Lucas Board this weekend.  I am having a little
trouble with it.  On the replacable 7474 at U9, I am having the best luck
with a 7474.  I havn't got a 74ALS74 to try yet, but the 74S74 and the 74LS74
don't work most of the time.  I really have to seat the board and the chips well
to get it to work at all.  I get a Green screen a lot of the time, which is
suppost to mean bad RAM chip.  When I hook up my Megaboard 2 and my SupraDrive
it is even more difficult to get the machine to boot, but with time it will boot.
I did the grounding fix while my machine was open.  (You connect the PALS ground
to the metal flange thing around the expansion connector, right?)

The problem I get is doing a SupraMount after normal boot up finally works.
Everytime the machine hangs doing a SupraMount.  I am calling Supra when they
open to see if they have any ideas.  (A normal boot in this case is actually
not having an s:startup-sequence so all I get is the blank cli.  I usually do a
Supramount first, and then run a startup-sequence off of my hard disk.)

I have a 16Meg Clock on the lucas board, and will get a 20Meg part when I find
one.  The hardest parts to get were the sockets for the 68881, and 68020.  BTW,
how much will I gain by using a 68882 insted of the 68881?

My wife found out that Leasure Suit Larry doesn't work with the 68020.  Copy
protection I guess.  I built the board with the 'keep the 68000 mod' in mind, so
I have a usable 68000 socket on the lucas board.  I wanted to do something like
this (drawing below) for the mod to keep things cleaner.

   ________ <-- 68000 in wire wrap socket on Lucas Board
  /        \
--|--------|--------------------------------------------- <-- Lucas Board
  |  ----  |
 -|-/----\-|- <-- Little perf board with 74244, resistors & capacitors on it.
  | |    | |
  |        |
  |--------| <-- Solder tail socket to solder wire wrap socket to.
  |        |
  ...

  Any problem with this?  I couldn't figure out a good place to put the
  extra stuff.

Thanks,
David