Does anybody have a source or replacement for LA120 DECwriter III ribbons?
I've actually got about 8 "new old stock" ones, still shrink wrapped, but
all that I've tried are pretty much dried out despite the shrink wrap. They
barely make a mark on the paper, even with the little print impression lever
cranked all the way up.
Thanks,
Bob
The Apple Lisa is complete, does not appear to be screen burned.
Includes hard drive and floppy drive and keyboard.
Somewhat yellowed due to age.
Does NOT power on, no repairs attempted.
(Is there someplace else to turn it on, besides the white square button
above the keyboard jack?)
Cindy Croxton
Electronics Plus
1613 Water Street
Kerrville, TX 78028
(830)792-3400 phone (830)792-3404 fax
AOL IM elcpls
_____
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2013.0.2805 / Virus Database: 2634/5952 - Release Date: 12/11/12
http://classiccmp.org/pipermail/cctalk/2010-January/282022.html
It always suprised me that hre BBC micro used the 6502 rather than the
6809. By the time the Beeb was designed, Acorn had made a 6809 processor
board for their System machines, so they must have had experience with
the chip. THe Beeb is nice, but a Beeb with a 6809 processor would have
been something else :-)
-tony
Hi! When I designed the N8VEM 6809 host processor it is loosely based on an
article I read for the BBC computer called "Dragon in the tube". I am not
very familiar with the UK microcomputers but apparently 6809 "coprocessors"
were fairly common peripherals on their Z80 and 6502 designs. I used a
similar concept for the N8VEM to allow its Z80 SBC to access the 6809 as a
"host processor" peripheral on the ECB.
One of the builders was able to get CUBIX running on the N8VEM 6809 host
processor using the Z80 as its "IO processor". However, I can see how the
implementation can get confusing because it is either a Z80 based system
with a 6809 coprocessor or a 6809 based system with a Z80 IO processor. In
reality it doesn't really matter but it's a matter of perspective.
The N8VEM 6809 CUBIX implementation allows the use of ECB peripherals like
IDE, video, floppy, serial, parallel, etc but it requires the Z80 to serve
all the IO based on 6809 commands. I added the 6809 IO mezzanine board
(power, ACIA, PTM, 2 VIAs, expansion bus) to give builders the option of
using the 6809 host processor as a stand alone computer or to add separate
IO to the N8VEM system when connected to the bus. The idea being to let the
6809 host processor interact with the outside world using its own IO and
only involve the Z80 when absolutely necessary.
The hardware seems to work OK but we'll see where the software goes. I
think with CUBIX the 6809 N8VEM system becomes a lot more practical. The IO
mezzanine fits on top of the 6809 host processor. You can see some photos
here. These are out of date but give a good idea. Recently I fitted an
improved serial cable and the nylon standoff hardware. Also the PTM seems
to be working and that's good.
http://n8vem-sbc.pbworks.com/browse/#view=ViewFolder¶m=m6809
I have many 6809 host processor and IO mezzanine PCBs so if anyone is
interested please let me know. This would be a great opportunity for anyone
who would like to do some 6809 hardware and software hacking.
I think the N8VEM 6809 host processor is the only system I am aware of other
than Dave's homebrew that is running CUBIX. There maybe some other homebrew
systems out there too I can't find them after some searching.
Thanks and have nice day!
Andrew Lynch
Hi guys,
I'm trying to get my hands on a 5.25in double-sided 40 tracks per side
"360K" floppy drive with the Shugart or IBM PC 34-pin connector (either
edge connector or pin header is fine). Does anyone have a spare they'd
like to part with? Slight preference for Teac or Mitsubishi, but
anything will do at this point.
I've checked Ebay, there are tons in the US (complete with "seller does
not ship internationally, don't even ask"), but the only ones I've seen
>from UK sellers are parts scalpers wanting stupid money for them (?149
"sold untested with no guarantee"? really?).
A BBC Micro 40-track drive would also be fine -- as long as it's native
40-track, not 40/80 track switchable or double-stepping (an 80-track
drive mated to a PCB which double-steps the head). Cumana, Viglen and a
few other companies made these, they were extremely common a few years ago.
I'm on the verge of getting DiscFerret write support working (at least
for UNIX PC disks) but the sodding thing won't read anything my 80-track
drives have written!
I'd rather not borrow the 3B1's drive - the DiscFerret is experimental
and a benchtop lashup is hardly an ideal scenario.
Thanks,
--
Phil.
classiccmp at philpem.me.uk
http://www.philpem.me.uk/
Hi all,
I am attempting to get Helios running on a 64-core T805-based Transputer
array. This is a one-of-a-kind system with a custom case. It uses a
single-board 486DX with 8MB of RAM on an ISA card for the host system. The
PC front end runs Windows 3.1 or MS-DOS 6. There are eight T805s on eight
custom cards. It doesn't use TRAMs, but I have a feeling these are wired
like such on the board. Pictures of the system can be found here:
http://imgur.com/a/fCA3C
I've been getting all of my Helios editions from
http://www.classiccmp.org/transputer/helios.htm. I first tried version 1.1,
and after copying the contents over to the hard drive from a single floppy
disk, running the server results in an error:
ns : Incompatible version of Rmap 6e627573
ns : error is fatal, exiting.
I finally got 1.31 working on the system by downloading another DOS
executable of the server and playing with some configurations. I also used
ispy and mtest to see the structure of the system, which uses several C004
cross links. Unfortunately, ispy only reports a single T805-25 processor
connected to the host at address 0x150.
Does anyone have any ideas as to why the other 63 T805s and several C004s
aren't showing up?
Thanks in advance,
Kyle
Dave,
> If the internal screen is fine then the syncs are at or close to the
> proper frequency, so any problems are going to be around the NTSC
> modulator, which would be fun to debug without a scope...
I do have a scope- poking about down in the chassis is difficult- I don't have
an ISA extension card. The composite trace drops down to the back side of the
card, comes up through a resistor, goes to the light-pen header, through another
resistor and vanishes into the middle layer. I could start just prodding with my
meter to see where it re-surfaces... but, well, yeah. A schematic would make
that easier.
The image on composite "tears" horizontally. I made a video of it, hooked up to
my TV set in the living room: http://youtu.be/a4jcKiSwUos
> On the other hand whilst I have never tried the Composite on CGA, but I
> have tried comparable modes on several other computers, including my
> rather old Atari STE, and a very modern Raspberry PI and it sounds like
> its working (almost) just fine. The composite out on CGA cards always
> was pretty useless, and "legible, just" pretty much describes any
> 80-colum output on composite. Try 40 a column mode (2 or 3)...
That's in 40-col mode, above. In 80-col it goes into a text mode rather like
MDA, which I haven't scoped to see if it's not present at the jack, or if the TV
refuses to display it. It's remarkably crisp, considering.
On a regular TV set (older, cheaper, no-name set)-
http://www.flickr.com/photos/philandrews/8657681921/
Above was trying to display this-
http://www.flickr.com/photos/philandrews/8660917851/
Admittedly that was all unbalanced, but I'm sure it should be a little better
than that.
> (Oh and my experience is with PAL, NTSC would probably be worse.....)
> If you have a TV with a SCART then the circuit below would work..
> http://www.electroschematics.com/377/
> but I guess you are in the US and and your TV will have CYMG inputs.
> Actually that circuit would probably work with CYMG but the colours
> would be wrong.
Yeah, I should have said. I moved out here to the States a number of years ago
now. My TV sets have all the usual "modern" inputs for here, CATV (NTSC
modulated), Composite-in, YPbPr component, HDMI and the one in the bedroom has a
VGA-in.
> If have a modern LCD TV with a VGA input you could try something
> similar, but leaving the syncs separate and feed it into the VGA. This
> might sound daft but often LCD TVs will sync to normal TV on the VGA. IT
> doesn't work with monitors, but it does with some TVs. As a quick and
> dirty test you could just use 470 ohms on all leads and omit the "I"
> line....
I can give that a try, but it's a band-aid to the symptom. I've got another
machine with CGA out and the TV displays it nicely. I'd like to be able to use
the composite-out because the machine has several games on that make use of the
timing inconsistencies in NTSC to create a larger color palette than the
standard 4. That would, however, be useful for other applications. It's been a
while since I've seen a SCART connector..!
> Dave
> --
> Dave Wade G4UGM
> Illegitimi Non Carborundum
Carl has a large "Marquette MUSE system" system for sale in Memphis, TN.
MUSE=Marquette Universal Storage for Electrocardiography.
It's DEC-based, not sure of the specifics.
See pics here:
http://oldcomputers.net/temp/muse-1.jpghttp://oldcomputers.net/temp/muse-2.jpghttp://oldcomputers.net/temp/muse-3.jpg
Pick-up required.
Contact Carl if interested: Carl E. Osborne Jr. - carl at datamed.com
------------------------------------------------------------------
History:
Marquette?s forte? was the acquisition and storage of cardiology
records, specifically electrocardiographic data (ECG/EKG), using
mainframe Digital Equipment Corporation (DEC) PDP-11 computer systems.
They were large ECG management systems that stored electrocardiograms on
300MB CDC 9448 hard drives.
The last time I had a chance to tinker with my malfunctioning PDP-8/A
with two RL02's was way back in Feb. 2013... here is the most relevant
tail of the old thread:
> The connections from the drive select outputs on the RL8A checked
> perfectly to the line receiver inputs on the RL logic board. While I
> appreciate Rick's taking the time to make me a selectable version of
> the RL02 oscillating seek.... he included a bug at no charge too ;)
>
> Specifically, the constant at 0230 (0100) selects the appropriate
> drive and resets it all right (0101 in AC). But - later on down the
> program, the SEEK (03) command is issued with another RLCB... however,
> the AC is forced to 0003 by the microprogrammed 7325.
>
> (As is probably apparent by now, the AC must have 0103 in it to select
> Drive 1).
>
> I edited the program to use a TAD 0231 and put the constant at 0231.
> So instead of the CLA CLL CML IAC RAL (load AC with 03 the hard way,
> an old-time DEC programmer's way to save one word when memory was a
> precious commodity) :) the AC now loads with 0103 and lo and behold,
> Drive 1 seeks merrily away! Restore the two constants to Drive 0 and
> THAT drive seeks. OK.
>
> However, all was not lost... during the couple of hours of chasing my
> tail wondering where the LSB of the drive select was going, I found
> that I had inserted the header into the RL logic board crookedly and
> bent two pins, one in the wrong hole and one shoved aside! :(
>
> Not only that, the line driver chip which provides the drive select
> signals had come from the factory with NO solder at all on its Vcc pin
> 16!
> =:^O
> Fixed that too.
>
> I think the OS/8 packs have been wiped out by now... various FAULT
> lights coming on, especially on the 2nd drive in the chain... going to
> build another system pack with VTserver which takes a good half-hour
> or more at 19200 baud. Hope the servo tracks are ok, otherwise I'll
> need to buy a couple of good packs!
OK. Last week I finally fired up the 8/A again. The problems had
actually gotten worse during the prolonged rest... I couldn't get
either drive to work this time (fault lights on both, as soon as the
Ready lights come on, even before any accesses). After much hair-
pulling and 'scope troubleshooting, I finally found (inside drive 1)
that I had improperly crimped one of the IDC connectors to the ribbon
cable, inside the bottom drive in the rack, where it was making a
variable resistance short between the two sector pulse drive lines!
So, having fixed that, I verified that Rick's oscillating seek program
works on either drive without faulting. Enter the constants for drive
0, drive 0 seeks no matter whether the first or second drive in the
chain as long as the unit 0 plug is inserted. Same for drive 1. Both
are not being selected simultaneously.
I also entered a short program to get the two status words, and that
reads the status of either drive correctly (idle, spin up, locked on
track 0, spin down, write protect button pushed).
Now, the original problem is still there, that OS/8 won't boot and the
RL02 faults (with either the original OS/8 pack that may have been
wiped, AND the remade one). Doesn't matter which drive is used as
Drive 0, or whether the new or the original OS/8 pack... Hit the BOOT
switch and Drive 0 audibly moves its heads, the fault light flashes
briefly, then it goes back to being ready (and of course OS/8 is not
running).
The interesting part is if both drives are loaded, then the fault
light on *both* drives flashes, then they both go ready again!
I haven't recently tried disconnecting the second drive cable and just
running with one drive, but that wasn't working before, either.
I am not going to be able to sort this out (unless I use my ancient
Tek 7D01 logic analyzer triggered by the fault signal) without a
diagnostic pack...
Does anyone have the diagnostic program set for PDP-8 and can put them
on an RL02 disc pack? I could either mail a disc to you, or I could
pay for one if a spare is available.
thanks for any help!
-Charles
> Message: 9
> Date: Wed, 4 Dec 2013 12:46:27 +0100
> From: anders at abc80.net
> To: cctech at classiccmp.org
> Subject: [Fwd: Restoration of a PDP-8a]
>
> Hi,
>
> I have started restoration of a PDP-8a model 8A420-CN. I doesn't have any
> schematics for this machine and I have searched internet for sources
> without any luck. The sets on
> http://bitsavers.trailing-edge.com/pdf/dec/pdp8/pdp8a does not include my
> version.
>
> My machine came with 16K*12bits core memory, 20 slot backplane and only
> the "Limited function board" frontpanel (don't now if this machine ever
> had the "Programmer's console").
>
> This is how my "Power distribution board" looks like:
> http://www.abc80.net/docs/pdp8/pdp8a/DSC_2118.JPG
>
> Some questions:
> 1. Is there anybody that could help me with schematics on this machine?
> Scans are preferred, but I can pay for paper prints. I'm especially
> looking for a diagram that matches the "power distribution board" that I
> got.
>
> 2. If I plug in the machine with only the regulator boards (2xG8018) and
> the limited function board in it, should the lights and fans come to life?
>
> 3. I suspect that my model shouldn't have "Power distribution board
> control", G8019 since my "Power distribution board" misses the connector
> for this board. Can that be correct?
>
> Any help is appreciated. PPD-8a is new to me, but I have some knowledge in
> the PDP-8 architecture since I restored a PDP-8/L that was in really bad
> shape.
>
> /Anders
>
What chassis is your -8A in -- is it the BA8-C as listed in
EK-0PDP8-SP-001 - PDP-8 Family Configuration Guide, April 1978 at
http://bitsavers.trailing-edge.com/pdf/dec/pdp8/omnibus/EK-0PDP8-SP-001_PDP…
The exploded view of the BA8-C is on page 41 of 217 of the MP00415 -
8A Family (Semi) Field Maintenance Print Set, April 1981 found at the
same source. Pages 50-56 show the "Power Distribution Board." The
Limited Function Board is page 57. The "Power Distribution Board
Control" is shown on pages 58-61. The 20-slot Omnibus is there too.
Can you list your modules/boards/etc. for us? You may have to pick
through the different drawing/schematic sets to find your individual
components.
The PDP-8 Family Configuration Guide will give much information about
your system and proper placement of modules. Page 2-10 (Worksheet,
8A420, 8A425) discusses your machine's layout. It says: "The BA8-C
power supply consists of two G8018 regulators; one provides 25 A at +
5 Vdc, 2 A at + 1 5 Vdc, and 2 A at -15 Vdc for the top 10 slots,
while the other provides the same current for the bottom 10 slots."
Figure 2-1 "PDP-8/A Computer Designations" breaks down the 8A420 as:
4 = CPU is the KK8-A
2 = CHASSIS is the 20 slot BA8-C
0 = CORE memory
The PDP-8 Family Configuration Guide doesn't explain the "CN" suffix,
but that looks similar to the suffixes listed in some of the
Engineering Drawings/Field Maintenance Print Sets for "Unit
Variations." There is a "CN" Variation of the 8A425 listed in the 8A
Family (Semi) Field Maintenance Print Set, but I haven't found a
description of it. ... I just found some of it. The 8A425 Parts
List on pages 24-25 lists the parts used in that version of the
semiconductor-memory 8A42x system. The parts that aren't obviously
semiconductor-memory-related may apply to your system too.
The pictures of your system show only the Limited Function Board, but
I _think_ that all -8As used the same Front Panels/Consoles, whether
they were the Limited or Programmer's versions. Perhaps you could
pick one up somewhere. I've got two or three Programmer's Consoles,
but all have one or more problems. The one on my 8A400 has a bad gate
on one of its quad-[I forget]-gate ICs, but I haven't replaced it yet.
Bob
Toby,
I'm away for the holidays, but I'd love an original XT for a console to run my 5364. I might also be able to contribute a few systems your sale if it's for a good cause. I have a couple RS/6000s I could stand to offload.
--Colin
Tobias Russell <toby at pdp11.co.uk> wrote:
>Hi,
>
>I've decided to have a clear out to raise some funds for the school club I
>run teaching 7-11 year olds computer programming, electrics and engineering.
>
>So here is what I have looking for a new home:
>
>- Lots of micro-vaxes (pizza box style)
>- Lots of microVax chassis (mostly unpopulated with cards)
>- Various Apple IIs and Apple II peripherals
>- Various terminals
>- SMD drives
>- BBC micros, Spectrums and ZX81s
>- Atari 2600's (woodies, darth vaders and jr's)
>- IBM PC/XTs
>- Misc PDP-11 parts (a few QBUS chassis, RX50s, TU58s, TK50s, QBUS cards,
>UNIBUS cards, PDP-11/44, RD,RF,RZ series hard drives)
>- Lots of other assorted items
>
>If anyone is interested in anything or would like to visit and dig through
>the stash get in contact.
>
>All the best,
>Toby
>
