Tony's comment, below... about the only equipment needed to repair... was
helpful.
So, as I have an Altair, a BBC, a KIM, a Sorcerer and various other beasties
awaiting ressurection, and having little (well, OK... no) electronics
experience, starting at square 1...
a) What should I be looking for in a logic probe. Any recommended models
(say, <$100)
b) Ditto for multimeter.
c) Where can I find a brain? :)
Actually, the Altair will be my first task. I'm thinking of #1 taking out
all the boards. Good idea?
I have it firing up and basically behaving, but some LEDs don't light when
they should, but are definitely able to light when they want to.
A
>Hmm... I've yet to find a classic computer fault that could not be
>tracked down using 3 things - a logic probe, a multimeter (DMM/VOM) and
>a _brain_. On the grounds that my brain isn't that good, I sometimes have
>to use other test equipment, but when I finally do track down the
>problem, I generally realise that the symptoms were obvious from the
>start if only I'd realised what they meant.
allisonp(a)world.std.com (Allison J Parent) wrote:
> [....] IO however while it would be nice to
> interogate or write to devices could leave the cpu "out of sync" since
> all IO is done from the accumulator.
You say that like there's something wrong with it.
Well, there could be, I suppose, if your hardware is such that reading
its registers changes them, and the operator doesn't realize this.
Was the latter really considered a problem in those days? Or was it
just that as a result it wasn't real useful to have the front panel do
that? (Or was it just the additional cost of having the front panel
do that?)
-Frank McConnell
<The only things I know about this board is that it's a SCSI controller, a
<it's BIG. It's about 10"x12", has an 86-pin edge connectr on the bottom,
<two 50-pin edge connectors on the top, and uses eight 2651 SCSI chips. It
<labeled "DATASTREAM ASSY 100716 REV A". Does anyone have any idea what
<this is for?
<TIA
Sounds more like an 8 port serial board! The 2651 is a USART type device.
The 50 pin connectors might be board to pannel connector cabling.
Allison
Anthony Clifton - Wirehead said:
>I see this problem alot at hamfests. You can't blame them. They want
>to bring what will sell and they're most likely to not have to carry
>back home. They perceive no value to ancient computers so they assume
>nobody else will either.
I have 2' x 3' white board taped to the little rolling cart I take with me.
On the board, I write down all the stuff I'm looking for that day.
=========================================
Doug Coward dcoward(a)pressstart.com
Senior Software Engineer
Press Start Inc.
Sunnyvale,CA
Curator
Museum of Personal Computing Machinery
http://www.best.com/~dcoward/museum
=========================================
Does anybody have any information on a North Star Horizon? I may be
acquiring one of these soon but don't know much about it except that
it has wooden side panels and used to support a half-dozen terminals.
Is it a S-100 bus?
Thanks for any help-
Marty Mintzell
< Does anybody have any information on a North Star Horizon? I may be
< acquiring one of these soon but don't know much about it except that
< it has wooden side panels and used to support a half-dozen terminals.
< Is it a S-100 bus?
Yes, I have one I built (and still use!) 20 years ago! Exteremely sold
piece of s100 hardware.
The top is wood too! Z80/S-100. Support for more than one user means
it was running a timeshare version of NS* Basic.
Allison
Hello,
I just joined the list. While I don't have any specific questions
_at_this_point_ :-) I have quite considerable experience with
electronics and am willing to help out where I can (time permitting)...
Of course I am always interested in software for my collection.
A quick list:
ZX81 with "real" keyboard, and of course 16k pack
TRS-80 model 1
Vic 20
C64
SuperPET with 4040 drive
Rainbow with 10Meg drive
Northstar Advantage
Bits'n'pieces of 2 PDP-11's (-23 and -73(?))- enough to have one
working in debugger mode
- no drives or anything
MicroVax II with periphials, had it running Ultrix and NetBSD
HP 75D and a few old HP calculators
128k Mac and Mac Plus
The next two are my everyday use computers. Dubious if they count as
"classics"...
Amiga 3000 (AmigaOS 2.04, and NetBSD until the HD with the root
partition went south...)
SparcStation 1+ running NetBSD
(NOTE: those are my home computers. Needless to say here at work I use
the usual unspeakable... though occasionally I do reboot my computer
into FreeBSD - but then I can't receive mail from the $%#& exchange
server)
I am hoping to aquire a (brand unknown) S100 Z80 box in the next few
days...
Joachim.
jpero(a)cgo.wave.ca wrote:
>Early high end Dell series (I think!) had this dot matix that glows
>yellow and rare motherboards that had POST display built in.
Back in those days, they were known as PCs Ltd. I had a 286 like that.
- John
Jefferson Computer Museum <http://www.threedee.com/jcm>
Here's a couple more for the TRS knowledgeable.
>from a TRS novice.
1. Among the various TRS stuff I picked up recently was a
TRS-80 monitor. It has a similiar connector coming out
the front as the Model II. Was this the for the std. M.1
and M.3 ?
2. Included with a TRS CoCo 1 I picked up last summer was
an adapter plugged into the cass.port. a label "TotalCommunications"
on one side and "Telelearning" on the other. Into this was plugged
another M/M adapter labelled " RS232 Gender Changer" Was this for
hooking up a fdd and/or modem ?
ciao larry
lwalkerN0spaM(a)interlog.com
> Could you tell me just a bit about the DL8? What does it look like, does
it
> work, any software... manuals?
I have no Doco or software for the DL8a, from memory there may be something
in
ROM, but I know that some of the ROM sockets are empty. It is contained in
a
single 19" rack mount case, mainly made from aluminium. On the back panel
there
is the fan, the power connector and a single female 25 pin D connector (I
think
it's a current loop port). The front panel is white with black lettering.
All
switches are toggle swicthes, some have red hoods, some have blue. I think
there are seperate banks of switches for address and data as well as the
usual
halt, run, examine, etc. All the LEDs are red. I have powered it up and
watched it count in binary, but as I don't know 8080 and have never
programmed a
front panel system I haven't done anything else
Does this ring a bell for anyone?
A
