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Re: [Altair Computer Club] Digest Number 258

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  • Allison Parent
    inline comments... ... Mine was ordered December of 1974, when Poptronics het the box I was there. It was very low (xxx200) serial number. Nearly all the
    Message 1 of 11 , May 16, 2006
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      inline comments...

      --- In altaircomputerclub@yahoogroups.com, "Steve" <alltare@...> wrote:
      >
      > Allison Parent-
      > I have had much better luck with the 8800 than you had. I still own
      > an original 8800 that I bought at a MITS surplus sale whien they were
      > still in business. Other than having a beefed-up power supply, it is
      > unmodified. I rented it to an accountant for a few years (back about
      > 1980), who used it daily. It had two or four 4K static RAMs, two 16K
      > Static RAMs, floppy controllers, and a 2SI/O, and never had a serious
      > hiccup.

      Mine was ordered December of 1974, when Poptronics het the box
      I was there. It was very low (xxx200) serial number. Nearly all
      the mods done were documeted by MITS in later days in early 1975.
      The only one of mine that was the 8224 mod as I despise oneshots
      for critical apps and I considered the clock critical.

      One of the things everyone sorta knew(fould out later) was the TI
      oneshots were better than National or Moto in the front pannel for
      example.


      > All of the Altairs had unterminated buses, so there was always the
      > possibility of ringing. The noise and ringing were enough to bring a
      > modern computer to its knees, but the Altair ran slow enough that it
      > would usually just ignore the "ghost signals". Memory was the most
      > susceptable to bus signal artifacts, but one trick that helped a lot
      > was to put the touchiest memory cards as physically close as possible
      > to the CPU board, where the bus's S/N ratio was the greatest. This
      > was particularly effective with the MITS 16K dynamic boards.

      They were a minor problem. The 88S4K rams were fussy until the mod
      came out and then later the "upgrade" to 884MCD cards.

      > Obviously, your experience was different, but most people didn't have
      > to resort to the extremes that you did, beyond correcting the power
      > supply and making sure the one-shots were timed right.

      I was early adoptor and I was not alone with the problems.

      I still have that machine and a 8800BT, both working.

      > The 8800b model took your advice- The CPU board used an 8224 chip,
      > and all 3 power supply voltages were robust, using a huge transformer
      > and big filter caps.

      The PS was a problem.

      Allison

      > steve
      > ========================
      >
      > --- In altaircomputerclub@yahoogroups.com, "Allison Parent"
      > <kb1gmx@> wrote:
      > >
      > > --- In altaircomputerclub@yahoogroups.com, "Steve" <alltare@> wrote:
      > > >
      > > >
      > > > Those early Altairs had all kinds of timing problems.
      > Thankfully, the
      > > > model B referenced everthing to the system clock and most of those
      > > >bugs disappeared. They never did get the hang of dynamic
      > memories,
      > > >though.
      > >
      > > Not on a bet, only some of the worst bugs. I have one of the
      > earliest
      > > ones. Powersupply was too weak to support 16k of S4K ram and IO,
      > CPU
      > > clock plain sucked as it relied on oneshots, bus ringing was problem
      > > too.
      > >
      > > To make it work passibly ok the backplane was replaced with a two
      > > sided WAMCO part with terminators, Power transformer rewound, filter
      > > cap values increased, CPU clock logic replaced with 8224 (Intel
      > clock
      > > gen). Most of the real problems really didn't show till you have
      > > 12-16k of ram and some IO while running BASIC.
      > >
      > > > I have a few CCS boards, but have not seen a 2200 computer "in the
      > > > flesh" that I can recall. Is this the one?
      > >
      > > I have a complete CCS2200. It's a nice machine and smaller than
      > some
      > > but has robust powersupply. Great machine!
      > >
      > > > <img src="http://www.computercloset.org/ccs.jpg
      > > > <http://www.computercloset.org/ccs.jpg> " height="373"
      > width="640">
      > > > http://www.computercloset.org/ccs.jpg
      > > > <http://www.computercloset.org/ccs.jpg>
      > > >
      > > > =======================
      > > > --- In altaircomputerclub@yahoogroups.com, Dave Sroelov <dave@>
      > > > wrote:
      > > > >
      > > > > steve,
      > > > >
      > >
      > >
      > > > > i think the biggest niggly little gremlin i had was the
      > original clock
      > > > > circuitry. when the first load came out of the factory, the
      > clock
      > > > > circuit was completely screwed up, big time. after that was
      > fixed
      > > > > everything worked fine. i must admit, the two ton transformer
      > and
      > > > > capacitor were amusing as well. i started my company in 1976
      > with that
      > > > > machine, and used it exclusively for the first four or five
      > years. now
      > > > > it's been thirty years and i'm still around. must be doing
      > something
      > > > right.
      > > > >
      > > > > but i digress, so back to the question at hand...
      > > > >
      > > > > the CCS 2200 series was a Z-80 based S-100 machine, made by a
      > company
      > > > in
      > > > > sunnyvale called California Computer Systems. they were clearly
      > aiming
      > > > > for business grade machines and didn't make kits. it was really
      > a nice
      > > > > little contraption, but the company is long dead, along with
      > all the
      > > > > rest of them.
      > > > >
      > > > > dave
      > > > >
      > > > >
      > > > >
      > > > > altaircomputerclub@yahoogroups.com wrote:
      > > > >
      > > > > >Message 3
      > > > > > From: "Steve" alltare@
      > > > > > Date: Fri May 12, 2006 10:51am(PDT)
      > > > > >Subject: Re: working altairs
      > > > > >
      > > > > >
      > > > > >Dave-
      > > > > >
      > > > > >It's great that you still have the Altair that you built.
      > That's a
      > > > > >keeper. I built an 8800b from a kit, and I still have it too.
      > I now
      > > > > >wonder how I had the patience to do it. It almost worked the
      > first
      > > > > >time I plugged it in. My only goofs were a blob of solder in
      > one of
      > > > > >the 100-pin sockets and one cold solder joint.
      > > > > >
      > > > > >Your CSS 2000 is an unknown one to me. Is it an 8080 machine?
      > > > > >
      > > > > >That reminds me of the Pertec PCC 2000. Does anyone in the
      > forum
      > > > > >have one of those? It was made by MITS after the takeover,
      > using an
      > > > > >8085 CPU, a pair of 8" internal floppies, and a "P-100" (not S-
      > 100)
      > > > > >buss. It's a pretty rare bird- not a single picture to be
      > found by
      > > > > >Google or Yahoo.
      > > > > >
      > > > > >steve
      > > > > >
      > > > > >
      > > > > >
      > > > > >
      > > > >
      > > > > --
      > > > > Dave Sroelov
      > > > > A & S Computer Services, Inc.
      > > > > 2813 Carriage Meadows Drive
      > > > > Wake Forest, NC 27587
      > > > >
      > > > > Tel: 919-554-4388
      > > > > Fax: 919-554-9431
      > > > > email: dave@
      > > > >
      > > >
      > >
      >
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