[Coco] Midwest VCF
mmarlette at frontiernet.net
Tue Sep 27 12:54:34 EDT 2011
Too bad for you....Mine just increased in value! :)
Mine is sitting next to my main workstation. A memorial of where it all started! :)
Next to that are three rooms full of CoCos and hardware. :)
----- Original Message -----
From: "gene heskett" <gheskett at wdtv.com>
To: coco at maltedmedia.com
Sent: Tuesday, September 27, 2011 11:45:33 AM
Subject: Re: [Coco] Midwest VCF
On Tuesday, September 27, 2011 11:55:23 AM Mark Marlette did opine:
> Do you still have the Elf?
I wish, but no Mark, there was only one purchased, based on a presentation
I did to the GM at KRCR, one that I saw as a problem that was hurting our
commercial production. I didn't even get to where I was talked out before
Dick said lets do it. I guess I must have made a good case out of what was
200% blue sky at the time.
So I bought the single board, ($250 IIRC) spent about 6 weeks playing with
it, seeing what it could do (remember I'd never seen anything more than
better calcs like the TI SR-51 at that point), and getting an idea of how
much I'd have to do in hdwe that it couldn't, and then miss-cued on the
video because I first used a video clock chip but the characters were way
too small, so I had to stop and design a board to make big characters,
which took me 3 or 4 days, then a couple of weeks to collect the stuff and
make it, using an 74ls154 (151? Memory is hazy now) to select the pixel
left to right, and a diode matrix to construct the figures from each nibble
of a byte. Decimal point hard coded. The memory board, and Quest was
selling a cabinet that resembled a mini cash register, but the s-100 & I/O
stuff occupied the overhead where the registers display would have been.
The left to right scan was timed by house HDrive & a 555 to adjust it for
centering, ditto for the vertical centering, and some dividers so that when
the vertical 555 timed out, it loaded the first data byte into an 8 bit
latch, and for the next 3 scan lines that was repeated, then another byte
was fetched (by dma) which was the next 47 lines, the vertical bars of the
top half of the character, then another fetch at the 50th scan line for the
center of the char, line 53 fetched the vertical bar data for the bottom,
displayed for another 47 lines, then line 100 was the bottom, and a 6th
null byte was fetched at line 103 to stop the bottom of the character.
Those line numbers are from the end of the 555 cycle, so it could be
centered both ways. That was sent through a cmos hex buffer all in
parallel, and mixed with house sync, and insert recorded from 9.59 seconds
before 1st video, to 2.0 seconds before first video, so a 5 second preroll
could be done, both by hand or by the station break machine.
I'd probably buy one on the spot if I could ever run across one of them,
I'd like to build another just for my own museum. I already have the EDISK
I made for WDTV back in the 80's which was used non-stop till about 6
months before I retired in 2002.
> It was my first computer, learned how to hand assemble in high school.
Yes, with the RCA manual (MPM-201c, I still have mine) in hand, it was an
> Worked for an Energy Management System firm on the manufacturing
> side..They used the 1802....
Its still used in oil & gas exploration as its radiation resistance allows
it to be used downhole using alpha scattering techniques to find gas and
oil deposits. We did have a company here in Weston that used that, but the
hot sources had to be handled with care because they were really hot, and
eventually their 'brain' on that stuff left for Florida and some TS
military stuff where he could get paid 5x for less exposure. The local
company couldn't find anyone to replace him at a price they thought was
good (damned MBA's), and had to reinvent themselves as a normal well
The brain? (he may have had an IQ in the 120's, no match for me at the time
20+ years ago) tried to reach back up from FL and hire me 2 or 3 times, but
I'm not a fan of the FL environment & kept asking for details he couldn't
supply because of the TS thing, so it never led to an actual on site
interview. Just as well IMO, I was happy doing what I did best here. I
was by then 'settled in' here & married to a local school teacher.
> Very cool when in high school, engineer was great, taught me a lot.
I too have had some interfacing with some that weren't afraid to teach,
good lessons learned.
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
"Professional certification for car people may sound like an
oxymoron." -The Wall Street Journal, page B1, Tuesday, July 17,
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