Path: utzoo!attcan!telly!lethe!torsqnt!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!hellgate.utah.edu!uplherc!esunix!blgardne
From: blgardne@esunix.UUCP (Blaine Gardner)
Newsgroups: comp.sys.amiga
Subject: Re: PAL grounding help needed
Message-ID: <1541@esunix.UUCP>
Date: 21 Sep 89 14:37:19 GMT
References: <513@tw-rnd.SanDiego.NCR.COM>
Organization: Evans & Sutherland Computer Corporation
Lines: 30

From article <513@tw-rnd.SanDiego.NCR.COM>, by johnl@tw-rnd.SanDiego.NCR.COM (John Lindwall):
[A1000 expansion problems deleted...]

> The instructions I used for grounding the PALS came from Amazing Computing
> Vol 3 #3 (pg 58).  I also am aware of the corrected diagram they published in
> the next issue (pg 102).

The [corrected] Amazing Computing PAL grounding instructions are
correct. If the article didn't mention it, you do want to use a fairly
heavy gauge of wire for the grounding. 30 gauge wire-wrap wire won't do
you much good, you need something like 16-18 gauge, and tie it to a
solid ground point. I used the motherboard mounting screw next to the
power supply. I ran 18 gauge wire to the 4 PALs, and used a crimp-on
eyelet connector and a star washer to secure it to the motherboard's
ground plane with the mounting screw. Oh, just to play it safe, I
soldered the "solderless" crimp-on connector too.

One other thing that can make a big difference is switching the CPU for
a better part. The Motorola parts seem to have more fanout drive than
the Hitachi or Signetics parts. When I added a Spirit clock to my ASDG
Minirack and 2M board, the system became completely unstable. The PAL
grounding helped, but not enough. With Spirit's help, I swapped the
Hitachi 68000 for a Motorola 68000, and the system has been 100% stable
for about 3 months now.

-- 
Blaine Gardner @ Evans & Sutherland    580 Arapeen Drive, SLC, Utah 84108
Here: utah-cs!esunix!blgardne   {ucbvax,allegra,decvax}!decwrl!esunix!blgardne
There: uunet!iconsys!caeco!i-core!worsel!blaine  (My Amiga running uucp)
"Nobody will ever need more than 64K."    "Nobody needs multitasking on a PC."