[Coco] Old coco3 fixes

Gene Heskett gene.heskett at verizon.net
Wed Jan 6 22:35:03 EST 2010


Greetings everybody;

In poking around on my coco's hard drive tonight, I came across a couple of 
files that might be of interest to users of the real thing.

One of them is 'ls138fix.txt' which describes adding another 74ls02 to gate 
the 74ls138 used as the /SCS decoder, with the /read signal instead of 
driving it full time from just the E-Clock.

This patch is reported to fix the sparklies on the 1986 GIME, and reduce a 
huge data clash during the later portion of the E-Clock because 2 different 
sources are trying to drive the data bus at the same time.  I believe I did 
it to my coco3 a long time back, although I have a couple more that probably 
need it, including Dennis Scala's machine.  I recall it has the sparklies 
pretty bad.

This file, an extensive text description, which also contains a uuencoded 
schematic .gif IIRC, and a postscript edition of something, also uuencoded, 
is a bit over 35k in size, so I won't post it here, and I have never sent 
anything to malted media before, so what is the procedure?  I'm in with gftp, 
looking at the contents of the incoming directory, so I guess I'll try to 
send it there, as ls138fix.txt.  Done, I can see it in incoming.

So get out your soldering stuff & have at it folks.

-- 
Cheers, Gene
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)

Money may buy friendship but money cannot buy love.



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