Mark-8??? Popped some pictures up.

From: Jim Kearney <jim_at_jkearney.com>
Date: Tue Jul 16 10:04:01 2002

OK, duh, I overlooked the front panel picture where there are connectors for
all those ports, making the boards' functions kinda obvious.


----- Original Message -----
From: "Jim Kearney" <jim_at_jkearney.com>
To: <cctalk_at_classiccmp.org>
Sent: Tuesday, July 16, 2002 10:17 AM
Subject: Re: Mark-8??? Popped some pictures up.


> Looking at the custom boards, it looks to me like:
>
> - the boards mounted to the address latch are a cassette interface. The
one
> on the right is the modulator/demodulator and the one on the left appears
to
> generate various pulse widths. It's a little hard to make out the chip
> numbers.
>
> - the one on the input board adds 7 input ports
>
> - the one on the output board adds 3 output ports
>
> I think the crystal is missing... I don't see any added parts that would
> suggest an oscillator.
>
> It's possible, since the builder made all these new boards, that he or she
> hand-made the Mark-8 boards from the construction booklet too, making it
> even more rare.
>
> ----- Original Message -----
> From: "Andy Berg" <groovelists_at_yahoo.com>
> To: <cctalk_at_classiccmp.org>
> Sent: Monday, July 15, 2002 11:52 PM
> Subject: Re: Mark-8??? Popped some pictures up.
>
>
> > Very nifty!
> >
> > It is so amazing to have such knowledgable people a
> > click away - you all are great! :)
> >
> > I promise I'll stay away from the pots. I don't know
> > exactly what my immediate plans are for the fellow,
> > ahm... I'd love to get it up and working sometime.
> > I'll peer about online and see if I can scare up a
> > suitable surplus power supply of some type. This is
> > perhaps the oldest machine I've had the chance to work
> > on... I'm quite excited, but, I think somewhat
> > rightfully, nervous.
> >
> > Oh! I don't know if anybody would like such a thing,
> > but I put a little bit clearer picture of the CPU up
> > at:
> > http://66.30.18.171/MARK8/CPU3.jpg (Big file warning:
> > ~420K)
> >
> > --- Loboyko Steve <sloboyko_at_yahoo.com> wrote:
> > > This does look like a Mark-8 that's been modified
> > > (rather craftily) to use a plug backplane.
> > >
> > > I'll bet the control socket on the front is where
> > > the
> > > Front panel (or maybe EPROM or ROM or maybe even
> > > diode?) board would go. Keep in mind that ROMs of
> > > any
> > > kind were very expensive in 1974-6 for a home
> > > budget,
> > > and no one had programmers.
> > >
> > > There's a lot of glare on the 8008 CPU but I think
> > > this is an example of a VERY early package (there
> > > are
> > > at least 2 types of C8008 packages).
> > >
> > > If you actually intend to get this going, I'd be
> > > concerned about the Molex sockets. They are
> > > constructed using PURE EVIL and were unreliable when
> > > new. Judging from the chips utilized (some no-name
> > > chips) and the sockets I suspect that this was built
> > > by a very skilled hobbyist, probably an engineer or
> > > senior technician working at home.
> > >
> > > Also, definitely check that you have +5 and -9 on
> > > the
> > > 8008. You could damage it with one missing (and
> > > never
> > > mind the 1101's).
> > >
> > > Someone mentioned to me at the xtal on the mark-8
> > > was
> > > optional, and you might have an RC oscillator and
> > > one-shots on there instead. The clock was 2-phase
> > > and
> > > would require a scope to adjust so if you see pots
> > > don't adjust them.
> >
> > Thanks for the terrific PDF - I was hoping that some
> > kind person might've put the scans up as you did. Some
> > bedtime reading material, I think.
> >
> > and --- Jim Kearney <jim_at_jkearney.com> wrote:
> > > Definitely a heavily modified Mark-8. Look at the
> > > board prints towards the
> > > end of http://www.jkearney.com/8008/Mark-8.pdf
> >
> > Thanks again for everything!
> >
> > Andy
> > _____________________
> > groovelists_at_yahoo.com
> >
> >
> > __________________________________________________
> > Do You Yahoo!?
> > Yahoo! Autos - Get free new car price quotes
> > http://autos.yahoo.com
> >
>
Received on Tue Jul 16 2002 - 10:04:01 BST

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