johnl@tw-rnd.SanDiego.NCR.COM (John Lindwall) (09/20/89)
A recent posting of mine gave details of flaky behavior of my A1000 w/
KickStart Eliminator 1.3, Supra 4x4, and Starboard II. When the tech opened
up my A1000 he noticed I had grounded my PALS, but he said I had done it
wrong. He removed the wires I had installed.
I was thinking perhaps that this change may be the cause of my problems.
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).
If these instructions are wrong, please send me the correct method for
grounding the PALS. Some people mention they have connected to a ground on the
mother-board while oters do not.
--
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John Lindwall johnl@tw-rnd.SanDiego.NCR.COM
"Above opinions are my own, not my employer's"
Health is merely the slowest possible rate at which one can die.blgardne@esunix.UUCP (Blaine Gardner) (09/21/89)
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."