2 Jun
2007
2 Jun
'07
7:26 a.m.
I've been working on a pcb design for a S-100 prototype board. I noticed
a few people on the forums asking about this. I decided to make this
since this is a big hobby of mine too(member-MARCH club). I based this
design on a old prototype board I kept back from the S-100 days. It's
made by Electronic Control Technology.
Here's a link to the picture
http://pghvintage.home.comcast.net/p...otypeboard.jpg
<http://pghvintage.home.comcast.net/pics/S-100/s-100_prototypeboard.jpg>
There were several different styles made before--each with their own
advantages. This prototype board(in pic) has the rows in a vertical
pattern to allow 300mil and 600mil DIP packages. It also accommodates 2
voltage regulators. Then there were some which only had a grid of solder
pads to allow any arrangement of 300mil and 600mil DIP packages.
I like to ask everyone what their preference might be in the arrangement
of the solder pads, eg: vertical rows, horizontal rows, grid, etc. If I
get enough feedback, I can include 2 different styles. It's not much
work to alter the design. I have a panel setup to include 2 pcb designs
at the moment, and it can be any 2 kinds of S-100 designs. In the
future, I like to setup a bigger panel to include several more S-100
designs.
Since this is mainly a hobby for me, I thought I might help out and
offer this service. I'm designing this from my home workshop and intend
to make this an affordable hobby. In case anyone is interested, with
enough orders(minimum 30) then I can offer these for only $15 each.
please send any feedback.
=Dan Roganti
--
[ My Corner of Cyberspace http://ragooman.home.comcast.net/ ]
2 Jun
2 Jun
1:09 p.m.
On Saturday 02 June 2007 10:26, Dan wrote:
I've been working on a pcb design for a S-100
prototype board. I noticed
a few people on the forums asking about this. I decided to make this
since this is a big hobby of mine too(member-MARCH club). I based this
design on a old prototype board I kept back from the S-100 days. It's
made by Electronic Control Technology.
Here's a link to the picture
http://pghvintage.home.comcast.net/p...otypeboard.jpg
<http://pghvintage.home.comcast.net/pics/S-100/s-100_prototypeboard.jpg>
There were several different styles made before--each with their own
advantages. This prototype board(in pic) has the rows in a vertical
pattern to allow 300mil and 600mil DIP packages. It also accommodates 2
voltage regulators. Then there were some which only had a grid of solder
pads to allow any arrangement of 300mil and 600mil DIP packages.
I like to ask everyone what their preference might be in the arrangement
of the solder pads, eg: vertical rows, horizontal rows, grid, etc. If I
get enough feedback, I can include 2 different styles. It's not much
work to alter the design. I have a panel setup to include 2 pcb designs
at the moment, and it can be any 2 kinds of S-100 designs. In the
future, I like to setup a bigger panel to include several more S-100
designs.
Since this is mainly a hobby for me, I thought I might help out and
offer this service. I'm designing this from my home workshop and intend
to make this an affordable hobby. In case anyone is interested, with
enough orders(minimum 30) then I can offer these for only $15 each.
Hmm, good question!
I have currently only two S-100 systems, a Cromemco System 3 with problems in
the PersSci drive. The floppy that was in the drive when I got it had been
in there and run so long that you could see clearly through the track zero
location. :-) I have some data on this stuff somewhere, and it appears
that they're using incandescent bulbs for such stuff as index sensors and
such? And the Imsai, here.
Got a Vector S-100 backplane too, that I've started to build, only I lack a
few parts. Most importantly the S-100 connectors themselves. :-(
I also have a couple of prototyping cards, I *think* they're Vector as well,
but haven't done anything with 'em yet to come up with a preference. I guess
vertical rows makes more sense in terms of air flow for heat dissipation?
That for the heatsinks for sure, though a lot of systems I saw mention of
later on in the popular period for S-100 seemed to be inclined to put a
regulated switching power supply in place and simply jumper across the
regulator positions. I dunno, to me the distributed approach always made a
lot of sense.
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
9:33 p.m.
Roy,
Thanks for the input. I was thinking about including one with vertical
rows and one with horizontal rows. That way you can have some flexibility.
One of the recent options for the onboard power supply was to use a low
dropout voltage regulator. This allowed boards to be installed in S-100
systems which contained either the original S-100 specs or the IEEE-696
specs. The latter have a lower power supply voltage on the
backplane(translates to lower power consumption) which an ordinary 7805
voltage regulator can't accept. These require at least a 10+ volts on
the backplane just to get a regulated 5V output. The LO voltage
regulators need only about 7V input to get a regulated 5v output.
The original backplanes were only 2 layer and couldn't handle the
current capacity. The local(distributed) voltage regulators were the
only option. You need at least a 4 or 6 layer backplane with a separate
copper layer for each voltage and then a layer for ground to have enough
copper for all that current.
=Dan
[ My Corner of Cyberspace http://ragooman.home.comcast.net/ ]
Roy J. Tellason wrote:
Hmm, good question!
I have currently only two S-100 systems, a Cromemco System 3 with problems in
the PersSci drive. The floppy that was in the drive when I got it had been
in there and run so long that you could see clearly through the track zero
location. :-) I have some data on this stuff somewhere, and it appears
that they're using incandescent bulbs for such stuff as index sensors and
such? And the Imsai, here.
Got a Vector S-100 backplane too, that I've started to build, only I lack a
few parts. Most importantly the S-100 connectors themselves. :-(
I also have a couple of prototyping cards, I *think* they're Vector as well,
but haven't done anything with 'em yet to come up with a preference. I guess
vertical rows makes more sense in terms of air flow for heat dissipation?
That for the heatsinks for sure, though a lot of systems I saw mention of
later on in the popular period for S-100 seemed to be inclined to put a
regulated switching power supply in place and simply jumper across the
regulator positions. I dunno, to me the distributed approach always made a
lot of sense.
1:42 p.m.
On 2 Jun 2007 at 10:26, Dan wrote:
I've been working on a pcb design for a S-100 prototype board...
For whatever my tuppence will get you today, I'd like to submit that
I'd prefer to see one regulator (+12, +5) at each corner, rather than
both at the same corner--better heat dissipation.
I'd also like to see a row of pads at the top for a 50-position
ribbon cable connector or two.
The orientation of the packages is fine. I'm assuming that the power
traces are duplicated on the reverse side of the board also.
I hope some of this makes some sense to others.
Thanks,
Chuck
9:41 p.m.
Chuck,
Thanks for the good ideas. I don;t recall amny S-100 with the regulators
at opposite corners, but then they did make a lot of designs back then.
The ones I own have them situated on the same edge.
I'll look in incorporating some of this into the design. The power
traces are double sided, I only made a pic of the bottom side before.
=Dan
[ My Corner of Cyberspace http://ragooman.home.comcast.net/ ]
Chuck Guzis wrote:
On 2 Jun 2007 at 10:26, Dan wrote:
I've been working on a pcb design for a S-100
prototype board...
For whatever my tuppence will get you today, I'd like to submit that
I'd prefer to see one regulator (+12, +5) at each corner, rather than
both at the same corner--better heat dissipation.
I'd also like to see a row of pads at the top for a 50-position
ribbon cable connector or two.
The orientation of the packages is fine. I'm assuming that the power
traces are duplicated on the reverse side of the board also.
I hope some of this makes some sense to others.
Thanks,
Chuck
3 Jun
3 Jun
5:29 a.m.
Thanks for the good ideas. I don't recall any
S-100 with the regulators
at opposite corners, but then they did make a lot of designs back then.
The ones I own have them situated on the same edge.
I've got photos of a good number of S-100 boards on my site which may be
useful as a reference. Click on the "S-100" title of the S-100 machine
section, or look at any specific machine and click on the installed boards.
There are a few which have regulators in opposite corners (SSM CB processors
for example), and a few which have refulators on opposite ends at the top
(eg: Cromemco System support), but most boards have the regulators clustered
together. What I find interesting is the number of boards where the regulators
are positioned away from the end with the power supplies, with traces running
around the outer edge of the board to carry unregulated power.
Dave
--
dave06a (at) Dave Dunfield
dunfield (dot) Firmware development services & tools: www.dunfield.com
com Collector of vintage computing equipment:
http://www.classiccmp.org/dunfield/index.html
10:01 a.m.
Dave,
thanks for tip.
I noticed from all the pics that the designs didn't follow one standard.
The one basic premise is that the regulators never sit below any IC's,
as this causes the heat to flow over them.
I see that the regulators are mostly on the left or top left, so that
the traces for the power input are kept reasonably short, from pins
1,2,51,52. The one trace that circles the board is the ground trace.
=Dan
[ My Corner of Cyberspace http://ragooman.home.comcast.net/ ]
Dave Dunfield wrote:
Thanks for the
good ideas. I don't recall any S-100 with the regulators
at opposite corners, but then they did make a lot of designs back then.
The ones I own have them situated on the same edge.
I've got photos of a good number of S-100 boards on my site which may be
useful as a reference. Click on the "S-100" title of the S-100 machine
section, or look at any specific machine and click on the installed boards.
There are a few which have regulators in opposite corners (SSM CB processors
for example), and a few which have refulators on opposite ends at the top
(eg: Cromemco System support), but most boards have the regulators clustered
together. What I find interesting is the number of boards where the regulators
are positioned away from the end with the power supplies, with traces running
around the outer edge of the board to carry unregulated power.
Dave
--
dave06a (at) Dave Dunfield
dunfield (dot) Firmware development services & tools: www.dunfield.com
com Collector of vintage computing equipment:
http://www.classiccmp.org/dunfield/index.html
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