Restoring an S100 system
gregg dot drwho8 atsign gmail dot com
I have here an S100 system who I believe was designed as a training
aid for I8080 assembler.
However when I attempted to start it, after making sure the right
fuses were plugged in, and so forth nothing happened.
No lights on the front, and not even a gleep on the terminal screen.
What suggestions are available about restoring its power supply?
---
Gregg
gregg dot drwho8 atsign gmail dot com
Barry Watzman
Linear supplies are trivial to troubleshoot. Switchers are difficult
without a schematic and/or experience working on them.
I hate to say this, but this is probably a linear supply, and the fact
that you ask the question suggests that you don't have enough
electronics knowledge to do this safely.
monahanz
>
> - Show quoted text -
I agree with Barry, the nature of your question and info provided
suggest limited knowledge of the system. Nothing wrong with that but I
would suggest you start reading up a bit on electronics, the web and
in particular on S-100 systems. There is a mountain of stuff available
these days. It's fun to do too.
To get you started see if there is +8 volts on pins 1 & 51 of the bus,
+16 volts on pin 2, and -16 volts on pin 52. If not power supply
problem to start with. Your first task, figure out how the pins are
numbered!
gregg dot drwho8 atsign gmail dot com
>
> - Show quoted text -
Hello!
Actually gentlemen I do know a fair amount of electronics. However I
got started in this business well after the S-100 based systems
supposedly became museum pieces. (I'll spare the both of you when I
revived my interest in them.)
Now as for your tips, that's next.
The other problem is that documentation on the old fellow does not
exist. I do know that everything is inside a standard chassis such as
the ones Altair and of course IMSAI used for their systems. I also
have here the text by Artwick who describes in extreme sense how the
basic S-100 system was first wired.
I suspect I have an interesting experience ahead of me, next month.
dott.Piergiorgio
> Now as for your tips, that's next.
>
> The other problem is that documentation on the old fellow does not
> exist. I do know that everything is inside a standard chassis such as
> the ones Altair and of course IMSAI used for their systems. I also
> have here the text by Artwick who describes in extreme sense how the
> basic S-100 system was first wired.
>
> I suspect I have an interesting experience ahead of me, next month.
I can suggest that you upload somewhere photos of the Machine in
question, and its board, power supply, etc. and posting here the
link(s), so people here can try to ID the machine and/or the board
and/or the PSU and give more useful tips, perhaps pointing to available
technical/maintenance docs ?
Best regards from Italy,
Dott. Piergiorgio.
Tarkin
If you are comfortable working with the dangerous voltage levels
inside the PS:
Power Off Tests:
- Eyeball check: look for cold solder joints, discolored pins, cut/
broken traces
- Capacitors : Check for bulging or discolored tops, shorts
- Diodes : My meter has a diode check function, if yours doesn't,
do it 'manually'
- Check XFormer : for open circuit or egregious resistance in the
primary or secondary
Power On Tests (with meter or logic probe [1], as necessary):
- Remove any 'extraneous' boards- maybe everything but the CPU and
memory board [2]?
- Check CPU, RAM, and ROM Vcc.
- Check the Clock(s)
- Check the address & data lines
- Add boards back in one at time, checking the above where pertinent
(current draw, too, if your meter can do it)
That should get you started.
[1] You can make one, google for schematics. I made one years ago
based off of
a Radio Shack Forrest M. Mims III "Engineers Mini Notebook" - I think
it's only
a couple of transistors and a couple of resistors.
[2] I'm not 100% about removing boards, there may be issues with
unconnected
lines?? I am not completely familiar w/ S100 systems.
HTH,
Tarkin
Barry Watzman
normally consists of a fuse and switch between the AC power line and the
transformer primary, and full wave rectifiers and huge capacitors on the
secondary. *** PERIOD ***
You indicate that the pilot light is not even turning on.
Anyone who knows anything at all about electronics could easily
troubleshoot such a power supply. Further, there are potentially lethal
AC line voltages in the power supply.
gregg dot drwho8 atsign gmail dot com wrote:
>
> Hello!
dke...@hotmail.com
Hi
Knowledge can be useful but to little can be dangerous!
We fully agree on this one. He sounds scary to me.
My guess is that he has a bad power switch. Many of these
had a grease inside to suppress arcing. This is most likely
dried out and not allowing contact.
It is just a guess but from the vast information he has given,
it is as likely as any. Just a guess.
Dwight
Herbert Johnson
> > > > Hello!
> > > > I have here an S100 system who I believe was designed as a training
> > > > aid for I8080 assembler.
>
> > > > However when I attempted to start it,...nothing happened.
> > > > No lights on the front, and not even a gleep on the terminal screen.
>
> > > > What suggestions are available about restoring its power supply?
You have provided almost no information about what you have. Any
advice or info you get, will depend on EXACTLY what you have. There
is no standard S-100 system, if you in fact have a "S-100" system; and
S-100 systems varied a lot anyway. What you can do to restore/repair
what you have, depends on your skills and tools plus docs plus
knowledge plus hints you get from others. That ALL depends on
identifying what you have.
Please describe the brand and model of your "S-100" system. If you see
a brand and model name/number on the power supply, please describe
that. If there are multiple boards in the box, please describe the
brand and model of those boards. Is "the terminal" part of the system,
does it work independently, ???? - brand and model please. Also,
please indicate if you have some skills in reading schematics,
soldering components, doing tests with voltmeters, etc.
(I'm not sure why my colleagues here are grasping at straws, trying to
GUESS what this person has and knows - instead of asking and WAITING
for his response. But it's wise to let this guy know there are LETHAL
voltages inside power supplies.)
> Hello!
> Actually gentlemen I do know a fair amount of electronics. However I
> got started in this business well after the S-100 based systems
> supposedly became museum pieces.
Can you do tests and repairs at the component level? Are components of
the 1970's and 80's something you know about? (BTW, one of your
respondents is a woman.)
> Now as for your tips, that's next.
>
> The other problem is that documentation on the old fellow does not
> exist. I do know that everything is inside a standard chassis such as
> the ones Altair and of course IMSAI used for their systems.
Again, there IS NO "standard S-100 chassis" either. Any S-100 system
can have any number of cards in it from any number of manufacturers.
The point of S-100 was to permit a variety of cards. As for "docs do
not exist", you might get some if you give brand and model info.
> I also
> have here the text by Artwick who describes in extreme sense how the
> basic S-100 system was first wired.
"The text by Artwick"? Who? What text? I had to ask Google Books to
find it: "Microcomputer interfacing
By Bruce A. Artwick, 1980" In any event, one S-100 book probably at
best only introduces you to what "S-100" means. It's a start, but it
won't help you fix your power supply.
> I suspect I have an interesting experience ahead of me, next month.
The more info you provide, the better and more precise help you will
get. It's really that simple. But the first "tip" is: there are no
standards for S-100 systems, or for that matter 8080/Z80 systems. NO
STANDARDS - these are not IBM PC's, they don't have "standard"
features or architectures or chip sets or peripheral devices. It's
simpler to make no assumptions, and just determine what you have,
there in front of you, and work from that.
Herb Johnson
retrotechnology.com
gregg dot drwho8 atsign gmail dot com
Hello!
I understand Herbert, I really do.
Actually I am very familiar with the TTL logic of the '70s and '80s,
simply because three quarters of my collection of parts are indeed
from that period.
Now as for the system, based on what I was briefed about from the
fellow who sold it to me, the chassis is a basic S100 system box as
originally designed by the fellows behind the Imsai and the Altair
(even the thing from Heathkit). As for the guts of the thing that is
indeed next up. Over the next few days I shall be posting a series of
photos concerning each board. Plus one of its power supply. '
Now the important things. Someone who normally does not post but
simply visited the list and found out that I was interested in
something like that.
He bought that one plus several others from an equipment broker
somewhere near where he lived.
He then came across my interests in obtaining such a case and decided
to make it available. The only thing to pay was its shipping costs.
He confirmed that it was possibly designed as a trainer for that
family of processors.
The big problem is that he wasn't able to provide anything else. Which
is why from the outset neither could I.
I shall be posting those photos later in the week.
Gekkor
<gregg....@gmail.com> said:
> Actually I am very familiar with the TTL logic of the '70s and '80s,
> simply because three quarters of my collection of parts are indeed
> from that period.
You have a collection of TTL chips, therefore you are very familiar
with digital logic. I smell a big load of bullshit, steaming hot in
fact.
gregg dot drwho8 atsign gmail dot com
> On 2009-12-22 13:37:20 +1000, gregg dot drwho8 atsign gmail dot com
>
> > Actually I am very familiar with the TTL logic of the '70s and '80s,
> > simply because three quarters of my collection of parts are indeed
> > from that period.
>
> You have a collection of TTL chips, therefore you are very familiar
> with digital logic. I smell a big load of bullshit, steaming hot in
> fact.
Hello!
And what are you getting at? One of the regulars wanted to me to
confirm that I was very familiar with digital logic from the time
period when the majority of the folks here, including myself, got
started. And I naturally confirmed it. None of mine is BS, and all of
yours is bantha droppings.
Point of fact, just because I learned CP/M-80 on an H/80-90 sort of
machine and have been staring at this S100 based box for the past two
years doesn't mean you need to be a Rude Rodney.
----
GCL
Tarkin
I think that person less-than-tactfully pointed out a flaw in the
logic
of the statement:
"Actually I am very familiar with the TTL logic of the '70s and '80s,
simply because three quarters of my collection of parts are indeed
from that period."
The implication is that ownership induces knowledge by some form
of osmosis. The word "collection", I think, is what throws people off-
I know it threw me. There are a lot of people who collect older
computer
and electronics components, kits, and systems, without having any
in-depth knowledge of how they work, or are made. They view said
components or systems as "investments".
A re-reading of your statement indicates that there is the possibility
you
own these parts as replacements, "spares". Which implies you might
know how to replace them. Which further implies the possibility of
an at least passing familiarity with power supplies.
I think also the negativity comes from the fact that you never address
whether or not you are capable and comfortable working with the
higher voltage and current levels in the power-supply section of a
S-100 crate. 5VDC@200mA is a far cry from household line voltage.
Knowing what a 74LS161 is and does will not protect you from ~115V,
or receiving a large dose of current from a large capacitor.
I think people would rather err on the side of caution and assume
that you know nothing about HV until you directly indicate otherwise,
perhaps with an amusing anecdote of working with HV, or even
just a plain, "Yes, I am well aware of the dangers of working with
the HV section of a power supply".
HTH,
Tarkin
glen herrmannsfeldt
(big snip)
> The implication is that ownership induces knowledge by some form
> of osmosis. The word "collection", I think, is what throws people
> without having any in-depth knowledge of how they work, or are made.
> They view said components or systems as "investments".
In the case of systems, especially ones with lights or buttons,
that might be true. Much more rare for things that don't have
a visual impact value. Some might collect ICs in ceramic packages
with the shiny gold top, but standard TTL is in plastic packages.
(I believe that military grade 54xx TTL is in ceramic, though.)
Of course if those TTL packages are on PC boards and connected
together to make a computer, then that is different.
-- glen
Gekkor
<gregg....@gmail.com> said:
>>
>
> Hello!
> And what are you getting at? One of the regulars wanted to me to
> confirm that I was very familiar with digital logic from the time
> period when the majority of the folks here, including myself, got
> started. And I naturally confirmed it. None of mine is BS, and all of
> yours is bantha droppings.
>
> Point of fact, just because I learned CP/M-80 on an H/80-90 sort of
> machine and have been staring at this S100 based box for the past two
> years doesn't mean you need to be a Rude Rodney.
> ----
> GCL
What I am getting at is that I seriously doubt you know very much at
all about TTL logic (except perhaps for the numbers which are printed
on their packages). You probably know the difference between 74SXXX and
74LSXXX for example.
Given that you have some boxes of TTL chips stored under your bed,
could you design say a frequency divider, or a video display
controller, an A/D convertor, an I/O address decoder, an interrupt
controller, a synchronous tri-state bus interface etc?
If you can't do this, then you know next to nothing about digital logic.
All...@localhost.net
Hello Greg,
This was asked.
>> Please describe the brand and model of your "S-100" system. If you see
>> a brand and model name/number on the power supply, please describe
>> that. If there are multiple boards in the box, please describe the
>> brand and model of those boards. Is "the terminal" part of the system,
>> does it work independently, ????
You answer bring us no closer to knowing that. It's helpful to know
so we can be specific as S100 was generic and also totally random
as to how it was implemented. I can say this as I have a wide
selection of the common and not so common S100 hardware and multiple
S100 crates all working.
For example there are multiple "flavors" of S100 power supply. Brute
force transformer/rectifier/capacitor, those that had a Constant
voltage transformer feeding the brute force rectifier and capacitor,
and those that had some form of regualtor either linear or LVSMPS.
By identifying brand, model or even cahhis vendor it's possible to
narrow answers about the PS and backplane.
Allison
gregg dot drwho8 atsign gmail dot com
> On 2009-12-23 03:06:58 +1000, gregg dot drwho8 atsign gmail dot com
Hello!
Actually, You are wrong. I can identify the entire range of chips made
by TI in the original Series 74 series, I've committed to memory the
ones I use everyday. I am also closely familiar with everything else
in the TTL families that TI made.
Oh and I do know considerably more then your "next to nothing about
digital logic".
I've also spent about the entire thirty years in this field.
But I'll leave that to the people who discuss the relevant natures of
the CV and other stranger then fiction stuff.
---
GCL
gregg dot drwho8 atsign gmail dot com
Hello!
P/S identification and the obvious board identification should be
online by the 26. I do agree with you that more information would be
useful here.
The chassis indeed one of the classic "Godbout" ones, that much I can
confirm now.
My big problem is that the information I was given was scant at best,
all he (the seller) could give me was that much, and also that the
name on its front which was "Digiac".
---
GCL
gregg dot drwho8 atsign gmail dot com
Hello!
I will add to my original statement that my collection of parts are
just that parts. They are ones typically selected on different parts
lists, also used by me for different breadboard based designs.
Actually Glen the mil-spec for logic is in ceramic bodies, the gold
based ones were space based.Although they did try out plastic bodies
on a satellite some years ago, it didn't survive its flight.
And alluding to my some thirty years in the field some of that were
spent sorting out the particulars of the desktop computers who arrived
for repairs or upgrade at a shop here in Queens. So in answer to your
questions, I am indeed comfortable with the idea of trying to repair a
P/S where there might be HV present or the regular voltages present
for the system. (Also respectful.)
--
GCL
Barry Watzman
coming on. Your problem has nothing to do with digital logic; right
now, you have a power supply problem, likely in the primary of a
conventional analog linear power supply.
Barry Watzman
constant voltage transformer. A few later "CSC" models were
non-compliant in that they supplied REGULATED voltage from a switching
power supply to the motherboard and the cards did NOT have on-board
regulation (very simple modification, just a jumper from the input to
the output pin of the 7805 or whatever regulator chip would otherwise
have been used).
dott.Piergiorgio
>> I shall be posting those photos later in the week.
>
> Hello Greg,
>
> This was asked.
OK thanks, I wait the photos prior of commenting again on the items.
(actuallly, i have *suggested* , not *asked* , for the record (and if my
wording was again unclear, apologies for this)
Dott. Piergiorgio.
All...@localhost.net
The Godbout are dirt simple using a CVT and brute force
rectifier/filter as are the more common Compupro (same outfit).
Barry did point out there are later Compupro (CSC) versions with
a more sophisticated linear supply but they are less common
and non-complient s100.
>My big problem is that the information I was given was scant at best,
>all he (the seller) could give me was that much, and also that the
>name on its front which was "Digiac".
That is usually the starting point. LIkely though that was a thrid
party reseller.
A written description of the boards often works as to what CPU
and any board level markings. Most vendors put their names
on the board somewhere visible. That would eb a starting point.
One detail: S100 systems could be a single vendor box like
Compupro or Comemeco or they could be a laundry list of
various boards from multiple vendors. It's not uncommon
these days to see a S100 crate that was populated with
random S100 boards that was never powered up being
sold because the owner had no idea what it was other than
"Ebay Rare".
Allison
>---
>GCL
Herbert Johnson
The personal crap is unacceptable posting behavior and irrelevant.
There's some other rules of use being ignored, and there' damn little
CP/M content being posted.
1) Posting photos in comp.os.cpm is not appropriate. This is a Usenet
newsgroup for discussions, not for posting software or documents or
photos. Those are not my rules, they are Usenet rules and common
practices (with the exception of one person who refuses to follow
them). They are old rules but they still apply. Mr. "Gregg", please
use a Web site for your photos. If you don't have one, there are free
photo-posting sites available on the Web. You can post links here
accordingly. There's no point to sending thousands of copies of your
photos to all the Usenet archiving hosts of comp.os.cpm. Many who read
comp.os.cpm will not be ABLE to see such photos in their Usenet
readers. Some Usenet archiving and distributing sites might reject
such posts as too big (for all I know).
2) I don't care about Mr. Glenn's professional or hobby resume, what
he knows or what is under his bed. He says he has some CP/M like
computer that does not work - it's reasonable to ask "what computer is
that?". When it comes time for repairs, then his resume comes into
play. It's about *the computer*, not about him, or his motives or his
attitudes, etc. etc.
3) No purpose is served to post "you're a jerk" "no, YOU'RE a jerk"
messages. That's troll behavior. Stop it. If anyone is a jerk, their
message content and history will make that apparent. The traditional
response to trolls and jerks is DON'T REPLY.
4) The point of posting in comp.os.cpm is not to show off. It's to
discuss software and hardware of and about the CP/M operating system;
in the context and rules of a decades old Usenet newsgroup with
archaic but long-standing rules of use. Start a blog or another
discussion group or a Web page, if your goal is to demonstrate what a
smart or great person you are.
I'm not the moderator, we don't have one, but comp.os.cpm has until
recently some consensus that good behavior and on-topic posting was
preferred and desired. But we've had a rough patch and some persons
have decided to break that consensus, or to ignore it. I won't
participate if that continues: what others do is up to them.
Herb Johnson
retrotechnology.com
Herbert Johnson
> 2) I don't care about Mr. Glenn's professional or hobby resume, what
That's "Mr. Gregg". However, trading anyone's resumes is not the
point.
Herb Johnson
MikeS
<snip>
>If anyone is a jerk, their message content and history will make that >apparent. The traditional response to trolls and jerks is DON'T REPLY.
> Herb Johnson
> retrotechnology.com
---
Hmmm... ;-)