Okay, I asked a simple question. Got 3 differnt answers, and folks
referring to "over here" and whatever.
I live in the US, I will need to go to radio shack to build this.
Which diagram is the safest, what parts do I need, and what do I do.
----------
> From: jpero(a)mail.cgo.wave.ca
> To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
> Subject: Re: IBM PCjr Allright?????
> Date: Monday, June 23, 1997 12:27 PM
>
>
> > Yes, I've seen that convention. But if you buy a transformer over here,
> > the connection tags will be labelled 0V and 17V or whatever. I've never
> > seen a physical transformer marked with a dot (that's not to say they
> > don't exist).
> Yeah, nothing marked to tell us of phases. :) So that invites
> mistakes by unwary who makes power supplies on their own. That why I
> offered warning. :)
>
> (hey, my power supply did not work...) eyes up. :)
>
> Jason D.
What am I making here? Do we know yet?
----------
> From: jpero(a)mail.cgo.wave.ca
> To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
> Subject: Re: IBM PCjr
> Date: Monday, June 23, 1997 9:51 AM
>
> Hello Tony,
> >
> > >From memory the central pin is chassis ground and the outside 2 are
18V AC
> > at about 3A.
> Actually 34vac 2amp center tapped transformer. The center tap goes
> to ground, what else how can negative voltages can be generated so
> it needs this ground. The both outside 2 pins for 17v ac lines goes
> there. The card rectify it to generate 3 dc voltages, two is
> positive and other one is negative. Bulk of the components is used
> to generate 5vdc, and a wimpy 12vdc source for the floppy drive and
> fan. And last one is in very small current negative current -12v dc
> which takes this voltage and go through a 7905 regulator to get -5v
> dc, both voltages are strictly for serial use and little use for
> else.
>
> Funny, instead of 60hz, you get the same type of circuit design in
> secondary side in lots of switching power supplies with few minor
> differences.
>
> The limits to overdrive if you do, both card and slot is due to the
> current limit allowance per contact on that slot. :( Leave it to be
> and parallel the seperate power sources to the sidecars if they have
> them. Another problem with this is that 3 connections is not enough
> to carry more than 2amp on each socket.
>
> By the way, I am Electomechanical major in training "on hold". :)
>
> > The manual doesn't give the schematics of the transformer unit (it does
> > for the PSU card in the main unit), and it's not clear from the
> > description whether the AC input is centre-tapped to ground or not.
> > Looking at the schematics, I think that it is _NOT_
>
> Oh yes, I did saw the techref for the outside PSU transformer is
> pretty simple just a disconnectable center tapped transformer.
> One thing I hated that they did not give us the that schematics for
> that power card module which I revsere engineered instead!
>
> Jason D.
The Color Computers were:
Color Computer 1: Silver/black, 4K-64K
Color Computer 2: White, 4K-64K
Color Computer 3: White, 64K-128K
Micro Color Computer: White, tiny, 4K
I've never heard of a TDP-100. The Color Computers had ROM BASIC and
most serious users ran an operating system called OS-9 which was kind of
like TopView.
Expansion is via the cartridge slot. The floppy disk interface was
implemented as a cartridge, with the floppy OS in ROM in the controller
cartridge. CoCo floppy drives are rare. Floppies stored 156K. There
was also a hard disk cartridge, believe it or not; plus, a Multi-Pak
Interface which allowed you to connect four different carts and switch
between them.
There are lots of CoCo fanatics around, somebody probably sells parts
and maybe even schematics.
In regard to the Inboard/386, as I recall it had 1MB 32-bit RAM on the
card, and could optionally use motherboard RAM which of course ran at a
much slower rate. My memories may be confused with the Inboard/386 AT,
but I seem to remember a daughtercard which could store an additional
2MB or so. Good luck finding a daughtercard though.
Kai
> ----------
> From: allisonp@world.std.com[SMTP:allisonp@world.std.com]
> Reply To: classiccmp(a)u.washington.edu
> Sent: Tuesday, June 10, 1997 11:01 AM
> To: Discussion re-collecting of classic computers
> Subject: cocos and stuff
>
> HI,
>
> In my non-op list of equipment I have three cocos apparently
> operational.
> They are of two different styles.
>
> The smaller is the TRS80 color computer with real keys on the
> keyboard.
> I have two of these one the case was wiped out, board is ok.
>
> The larger is TDP-100 personal color computer with chiclet keys.
>
> Lacking docs I presume these have rom Basic. What expansion is
> possible
> (there is a port) and how hard. Do they run any real OSs or some
> TRShack?
>
> What's the odds of finding DOCS especially schematics?
>
>
> I have a xt class machine with an Intel Inboard386...(works too!)
> what's the
> odds of finding schemtics or expansion ram for it? The 1meg of ram is
> tight
> for somne stuff. Currently I use it as a 10x faster xt.
>
> Allison
>
> %I've been looking for a Jupiter Ace for over 10 years! Do you have any
> %leads on them?
The schematics were printed in The Computer Journal last year sometime.
IIRC, The Computer Journal's URL is http://www.psyber.com/~tcj/.
> I have a jupiter ace. It's sitting is a closet somewhere back in
> Singapore.
>
> Another sign of the folly of my youth :
I have a Jupiter Ace hanging around, also. However, I just built it
last year. Unfortunately, I had to give the rubber keyboard and most of the
memory back to the fellow I borrowed them from; I haven't yet gotten around to
building a keyboard from aluminized mylar, cardboard, and Tyvek (this should
give me a working keyboard, but it will be of ZX80 quality). I've also found
enough 2114s in an old MDA card to bring my Ace back to life...
> the machine is stripped out,
> the TV modulator is missing
I don't have a modulator in mine. I gummed a 15-pin D connector to it so I
could drive a spare DEC VR201 I had lying around (yes, the VR201 apparently
does have enough range to do PAL; it worked great).
Roger Ivie
ivie(a)cc.usu.edu
Actually, I believe that Hot Coco was a mag published by Wayne Green of 80-Micro and Byte fame.
Regards,
Bob
----------
From: Mike Sprague[SMTP:sprague@VivaNET.com]
Sent: Sunday, June 22, 1997 9:40 AM
To: Discussion re-collecting of classic computers
Subject: Re: Cocos
e.tedeschi wrote:
>
> Just to help me understand better...when you refer to Cocos, do you
> refer to the Tandy TRS-80 COlour COmputers?
Yes. I don't know where the name origionally started, but the support
magazine Tandy put out was called Hot CoCo.
~ Mike
You aren't the only one who does old PC's...that's my business (I
recondition old XT/AT's and sell them. Send strange questions to me.
I also still sell an occasional Commodore piece!
> My main interests (although I enjoy reading all of this) is the older
> systems based on the IBM-PC (XT & AT class) machines and PS/2s which I
> know is a bit more current than many of you like. I also have a
> Commodore 64 and Plus/4 and periphs, I guess I can qualify based on
> that.
"A.R. Duell" <ard12(a)eng.cam.ac.uk> writes:
> I've never liked bit-banged serial ports either (except on
> microcontrollers). They always seem to have problems with full-duplex
> operation. Yes, Apple sold a bit-banged serial port for a time - I have
> one with the manual (which, amazingly contains instructions on linking it
> to an ASR33), presumably to save a UART chip. They then sold one that
> worked properly (in full-duplex mode, etc) under the name 'super serial
> card'. It used (IIRC) a 6850 chip (or was it a 6551?)
Hmm? What was that bit-banged serial port?
If you look in the Apple ][ red book, there is a little circuit
in there that plugs into the game I/O connector and drives a
20mA current loop. Alongside there is a short assembly program
to drive it. Now there is a bit-banger.
There was an unspectacular serial card for the ][. I don't recall it
being a bit banger, just that the combination of it and the printer I
was using at the time (an IDS BrighterWriter) wasn't smart enough to
manage any sort of common flow control, so that I had to run it at 300
baud. I thought it had some sort of UART-like thing, but maybe my
brain is going again.
Hmm, I think it was called the Asynchronous Serial Interface or
something like that. There was also a Synchronous Serial Interface
that (I recently found out) was the Silentype printer interface.
I don't remember the Mountain Hardware CPS card that well, and I feel
very good about that based on what I do remember. Now there was a
klu[d]ge.
The Apple Super Serial Card was designed around a 6551.
There were a couple of other cards designed around the 6850.
The Hayes Micromodem ][ was one of these.
...
Strange as it seems today (now that I have done some programming
around PC-contemptible serial ports), the Apple ][ serial cards and
software generally worked by software-polling-hardware. The only
serial card I can remember supporting interrupts was the Super Serial
Card, and I can't say that I ever saw it used that way. Certainly
none of the "standard" software required it; interrupts just weren't
generally done on Apple ][s.
-Frank McConnell
Does anyone know anything about the Vector 3-5030 from Vector Graphics?
Is it considered a collectable? I recently found one at the town dump
and brought it home. It displays some sort of ROM monitor screen when
it comes up with version number 4.2. It has a dual floppy drive but no
software. I assume it is a CP/M machine since one of the boards in the
S-100 card cage has a Z80 on it.
--
David Betz
DavidBetz(a)aol.com
dbetz(a)xlisper.mv.com
(603) 472-2389
Hello,
I guess it's about time that I introduce myself. I've been lurking here
for a month or better. I guess I really have not responded before
because I didn't really have much to add especially to the discussions
of late 70's stuff and the discussions of minis.
My main interests (although I enjoy reading all of this) is the older
systems based on the IBM-PC (XT & AT class) machines and PS/2s which I
know is a bit more current than many of you like. I also have a
Commodore 64 and Plus/4 and periphs, I guess I can qualify based on
that.
I really didn't start out to be a collector, but kind of fell into it.
The Plus/4 was the first computer my family ever had, so I've now taken
over the care and nurturing of it. I picked up my C64 a couple of years
ago from my former minister who had is sitting in his closet. He had
two 1541s, a MPS-803 printer, vicmodem, fast load cartrigde, joystick,
and monitor, plus a ton of software. He wanted $30 for the lot after I
enquired. I was in hog heaven but why wife rolled up her eyes and said
"What are you going to do with THAT!"
The XTs and PS/2s were give aways. I've really been having fun with the
PS/2 Mod 60 (a 286 w/ one 1M and 40M HD). I have been watching
AuctionWeb and have added pieces to bring it up to a '486 with 8 meg
with SCSI periphs.
One of the more interesting 'gives' I have since obtained is the Amstrad
PC1512 - It's an XT class machine with built in joystick port in the
keyboard (uses same joystick as C64), built it mouse port, serial and
parrallel built in with the expansion slots going left to right rather
than front to back. The power supply for the whole thing is in the
monitor. The case has a 'cutout' for the the stand of the monitor to
fit into. It also uses 4 AA bateries for the clock which are easily
accessible (move the monitor). It is really a neat design.
I live in Rochester, MN - so I'm not close to either coast (but Canada
isn't that far away)
Dan
> From: Paul E Coad <pcoad(a)crl.com>
> Subject: Re: Who was in Australia?
>On Fri, 20 Jun 1997, Kai Kaltenbach wrote:
>> Subject: Mint Commodore PET FOR Sale
>> From: "Stephen McCoy and Charmiane Barr"
>> <mrsmrx(a)efni.com>
>> Date: 1997/06/17Message-Id:
>> <01bc7b43$fddee5c0$b8933dcf@charmaine>
>> Newsgroups: aus.computers.amiga[More Headers]
>I'll bite on this. How much is one of these worth? I have almost
>zero experience with PETs having only seen 2 in person. What are the
>relative rarities of the various models of PETs? Did they make a
>bunch of them? Are they really common in some places and pretty
>rare in others?
As everyone says worth is a relative term, some computers that hvae high
perceived values are given to people, etc. This is a question YOU have
to answer as a collector, no one can set your price for you.
Well alot of the PETS were purchased by schools and some businesses,
prices for the computer back then when they were new (1977-1981) ranged
>from $700-$1,200, disk drives were about $1,000 for a dual drive model.
Nowadays in my region of California schools have been ridding themselves
of them at a high rate. The computers are not too terribly hard to come
by but the drives are harder to find.
Rarity? Hmm, probably the most interesting is the original series
with it's colorful calculator-style keyboard (circa 1977) and in-case
cassette unit. Next I would say is the SuperPET (circa 1981, the last
of the line, which I described about two digests ago) with it's
mainframe-friendly, multi-language ability. All units had monochrome
displays and either 40x25 or 80x25 screens (no hi-res graphics without
3rd party hardware), the BASIC is almost exacly the same as in the
Commodore 64 or VIC-20 and uses a 6502 processor. Memory ranged from
the first 4k units (a short run), 8k, 16k and 32k with some of the
latter 80 column machines sporting 96k expansion bnoards. There are a
few collections of programs available on the internet with most still to
be re-discovered.
>The ones I have seen are pretty cool looking in a retro-future kind of way.
That's true, back then they 'looked' like a modern computer, more
than some of the other computers (which looked like the steel boxes they
were in). You can spot them as props in movies now and again (Star Trek
II, in Kirk's apartment).
They were fun, and they were pretty good even for their limitations.
If you are a fan of Commodore computers it is a nice addition to have
some PETs in the house. ;)
>Also note that whois reports that efni.com is in Canada. The machine
>might not be in Australia.
Commodore was pretty big for a good while in other countries as they
had the foresight to start manufacturing plants internationally (Germany
was probably one of its largest). As far as shipping a PET it would
require a very sturdy box about the size needed for a 19" television and
would weigh 30 to 40 pounds.
--
Larry Anderson
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