original value?
-tony
e an Elliot optical reader, or maybe a Trend. Those can
run continously if you engage the pinch roller solenoid, alternatively
you can control the solenoid (and the brake) to step the tape a
character at a time.
And FWIW both of those readers need sprocket holes.
-tony
les?
If a paper tape reader that doesn't need sprocket holes exists, could
somebody post the make/model and preferably a link to a manual for it.
-tony
venge parts).
>
> I seem to recall backed up tape forming a loop rather than rewinding
> onto the spool.
Yes, the main use of this facility was to immediately correct a typo
by backspacing the tape and overpunching the incorrect character with
all holes. You didn't need to rewind the tape if you only have 1/10"
of it to bother about.
-tony
s started
punching holes properly it will carry on.
It could use tape with pre-punched feed holes, but equally it can use
unpunched tape.
-tony
On Fri, Jun 27, 2025 at 11:29 AM Frank Leonhardt via cctalk
wrote:
>
> On 24/06/2025 20:16, Wayne S wrote:
> > On Jun 24, 2025, at 12:10, Tony Duell wrote:
> >> On Tue, Jun 24, 2025 at 8:04 PM Wayne S via cctalk
> >> wrote:
> >>> There’s really a
00 or HSR500.etc.
A paper tape may be damaged after a few passes through a mechanical
reader but will be good for hundreds of reads on one of type {3}.
-tony
gt; a punch.
Every paper tape punch (Teletype, Friden, DEC, Facit, Data
Dynamics...) I have punches the sprocket holes along with the data
holes. Some need a bit of help (pull the tape by hand) to get started
on a new roll of tape, but once it starts punching properly it will
continue to do so until the roll runs out.
-tony
. This ROM for the HP9830 is
surprising common in my experience.
-tony
hink the tape unit was still all TTL.
FWIW I am sure I've seen single tape drives with a pair of RS232
sockets on the back to link between a terminal and modem and give
'ASR' facilities -- recording data to tape in blocks and replaying it
later.
-tony
is not obvious from the manuals I have.
-tony
e slightly off-centre notch in the rear edge.
-tony
paper tape punch is the actual
punch/die assembly. They have to fit very accurately to give clean
punching and be the right diameter to make holes of the right size.
Oh, and you need to harden them properly.
-tony
On Fri, Jun 20, 2025, 2:09 PM Paul Koning via cctalk
wrote:
> I'm always puzzled by "local only" offers. It's expected that shipping
> costs get added, but why would a seller make a decision that shipping is
> "too expensive"? Logically the buyer should decide that, and if the buyer
> will pay
propan-2-ol (isopropyl alcohol) gets
most of it off.If the goo gets on your hands, stop and wash them
thoroughly. This is not because the goo is particularly harmful, but
rather because if it's on your hands you'll transfer it to anything
you touch
-tony
On Wed, Jun 4, 2025 at 6:19 PM Mike Katz via cctalk
wrote:
>
> Tony,
>
> Rubber has a tendency to do that.
I repair Philips tape recorders Enough said.
(For those who've not experienced it, Philips drive belts of the 1970s
decay into a horrble sticky mess that gets
t). There were some rubber hammer caps
in there. Although they were packed in sealed plastic bags, they have
all turned to Evil Goo now,
-tony
On Tue, Jun 3, 2025 at 8:31 AM Tony Duell wrote:
>
> On Tue, Jun 3, 2025 at 4:39 AM Richard Schauer via cctalk
> wrote:
>
> > The tape controller (marked with a green dot on the connector on my
> > machine) was made in 1986. It is a full-length card, a Wangtek
> &g
On Tue, Jun 3, 2025 at 4:39 AM Richard Schauer via cctalk
wrote:
> The tape controller (marked with a green dot on the connector on my
> machine) was made in 1986. It is a full-length card, a Wangtek
> 30006-007 rev C. It has an 8085, 8257, 6264 SRAM, 2764 EPROM, what
> appears to be a chipset
rns syntax error. Go figure.
Have you tried :
DEFUSR1=(&H7D00)
DEFUSR1=&H7D00+0
I assume you're running TRS-DOS. What happens if you use LBASIC under LDOS?
-tony
o, would this have a floppy controller on it that was capable
> of reading and writing disks from systems like the TRS-80 with an SD
> boot track?
Alas not. The oriignal IBM controller is strictly double density (MFM) only.
-tony
ply, chosen because they are cheap and have
logic-level on/off switching, can be used to replace the missing
Philips board. So my bench is covered in bits of ATX power supply in
various states of dismantled-ness.
-tony
ue more
quickly.
The receive 'magnet' (solenoid) in a Creed 7 teleprinter (more common
that most Teletypes over here) will normally operate on about 12V. But
if you try a 12V supply the signals are so distorted that the thing
wll not print reliably. We used to use 80V with a suitable series
resistor.
-tony
ins of the same
DA15 (probably by only allowing one joystick, the orignal IBM adapter
allowed for 2)
-tony
nt), the plug will then spring forwards. There was a compression
spring in the back of the lock, forcing the plug forwards. I have
removed this now for the moment.
The in/out motion of the plug is controlled by a pin (the end of which
is the silver circle in the 'side' photo) running in a groove in the
plug.
-tony
>
> Regards,
> Walter.
>
On Thu, Apr 10, 2025 at 5:37 PM Fred Cisin via cctalk
wrote:
> Tony has removed the lock.
> It is not a keyway that a regular locksmith would have the right blank!
Certainly not in the UK. There are 2 types of 'lockswiths' over here.
The ones that cut common house/car keys (and
On Thu, Apr 10, 2025 at 3:02 AM Fred Cisin via cctalk
wrote:
> But Tony has already removed the lock. Either by picking it to open the
> case, or coming in through the back of the case. Locks on computer cases
> offer extremely little security.
To make some reference to a classic
h time consuming, and requiring som moderate machining skill, that
> >> looks like it shouldn't be an extreme problem to make a blank.
> >> I assume that Tony has, or has access to, a precision milling machine.
> >
> > It might not even need an automill. At the
gt; Would it be feasible to cut a couple of key blanks out of metal plate? Maybe
> metal
> strips?
Should be possible to mill them, but as I said I'd want to make
several identical ones which is a pain without CNC tools (my
lathe/mill are entirely manual). I can't believe it's a custom keyway
so blanks should exist for it.
-tony
n SE London, England. I think travelling over
6000 miles is a bit far :-)
-tony
On Tue, Apr 8, 2025 at 5:33 PM Paul Koning wrote:
>
>
>
> > On Apr 8, 2025, at 12:06 PM, Tony Duell via cctalk
> > wrote:
> >
> > ...
> > I think there is only one key. The lock is somewhat unsual though.
> >
> > There are 4 pins in the plug (t
On Mon, Apr 7, 2025 at 9:05 PM Fred Cisin via cctalk
wrote:
> although time consuming, and requiring som moderate machining skill, that
> looks like it shouldn't be an extreme problem to make a blank.
> I assume that Tony has, or has access to, a precision milling machine.
It wou
On Mon, Apr 7, 2025 at 6:27 AM Van Snyder via cctalk
wrote:
>
> On Mon, 2025-04-07 at 04:23 +0100, Tony Duell via cctalk wrote:
> > use a
> > blank to lift the pins so I can 'shim' it from the rear. Push out the
> > plug with the follower, remove and measure
On Sun, Apr 6, 2025 at 10:02 PM The Doctor via cctalk
wrote:
>
>
> On Sunday, April 6th, 2025 at 11:04, Tony Duell via cctalk
> wrote:
>
> > Does anyone know anything about the key lock on the mains on/off
> > switch of the P3800?
> >
> > I have one w
this thing as original as
possible.
-tony
d 'high' density. Whether this means it
just supports 2 write currents or also 2 speeds I am not sure.
-tony
Computer 2'
The CoCo 3 manual does not say TRS-80 on it through
-tony
C-09 under OS-9 on the CoCo of course. Quite the
finest 8-bit BASIC that I have ever used.
-tony
you have any idea where to find one.
-tony
t available to simply use an M3 screw and large
washer (turn it with a screwdriver) but it's easier with the knob.
[1] In any case making one was quicker and cheaper than playing
telephone tag trying to get an official one.
-tony
>
> Tony,
>
> That’s pretty clever. So basically
rives, G is 80
cylinder double head, high density (360RPM? -- 1.2MByte), and H is 80
cylinder double head high density (1.4MByte))
-tony
Philips P2000C) so
most of the photos are not of the drives, but there should be some
that show the head positioner, etc
And here's a home-made version of the positioner-moving tool. Not
essential, but it's useful to have.
-tony
https://www.flickr.com/photos/tony_duell/albums/72177720302945215/
replace the whole thing, trying to align the top head to
the bottom head if you want to replace only one of them is supposed to
be impossible in the field. It's not but it is not something to do
'for fun'
Anyway, once you've got the new head in, you test it on a scratch
disk, and then you have to do the radial head alignment etc, with a
special CE disk.
-tony
a 3 pin socket that fitted onto the middle 3 pins of
the headed on the 27C010 module. For normal operation in the Portable
Plus, pins 1-2 and 4-5 of that header were fitted with shorting links.
I can send you reverse-engineered schematics of all parts if you need them.
-tony
A 2838 card can be used instead of a 2723.
keith
rrent). It runs off a floating supply
from the transormer T1.
My guess is that using the 7924 in a similar circuit allows the
circuit to be turned upside-down and use a more common NPN darlington
transistor.
Is that what you have?
Is the common pin of the regultor firmly connected to the +24 output
rail? If not the output wlll go sky-hgh.
-tony
nal of the
regulator (and the +ve terminal of the floating supply that feeds it)
is +24V.
-tony
You can use a 2838 card instead of the 2723.
On Mon, Feb 3, 2025 at 2:08 PM ben via cctalk wrote:
>
> But open source should have fixed versions, if possible.
>
I'm not really sure what this means.Most open source projects have
defined release versions.
I might not want the latest C standard.
>
For gcc this is what --std is for.T
On Mon, Feb 3, 2025 at 12:45 PM Alexander Schreiber via cctalk <
cctalk@classiccmp.org> wrote:
> On Mon, Feb 03, 2025 at 07:08:32PM -, Donald Whittemore via cctalk
> wrote:
>
> On top of that: A lot of those LLMs are build on theft at an epically large
> scale. They hovered up everything in si
On Mon, Feb 3, 2025 at 12:51 PM Donald Whittemore via cctalk <
cctalk@classiccmp.org> wrote:
> If I don’t have the code expertise or compiling capability how do I know
> the executable is safe?
>
How do you know a closed-source executable is safe? Hackers have
installed vulnerabilities into
On Mon, Feb 3, 2025 at 12:42 PM Donald Whittemore via cctalk <
cctalk@classiccmp.org> wrote:
> If I am not proficient in the source language or have the ability to
> create my own executable I don’t see how open source is ‘safer’ for the
> average Joe or app.
>
I'm not seeing what *your* abiliti
On Mon, Feb 3, 2025 at 11:25 AM Paul Koning via cctalk <
cctalk@classiccmp.org> wrote:
>
>
> > On Feb 3, 2025, at 2:08 PM, Donald Whittemore via cctalk <
> cctalk@classiccmp.org> wrote:
> >
> > I am an old mainframe guy. I could give you my COBOL deck of cards or
> the compile listing. You could p
INDUSTRY STANDARD UART, with a external FIFO chip?
The DEC DZ11 uses the standard 40 pin 'dumb UARTS' and feeds the
receive data into FIFO ICs. I am sure there are others.
-tony
>
>
>
n board that
included a parallel printer port. To avoid confusion, this was a DB25
plug. But the board had been laid out for a DB25 socket using the IBM
PC pinout. The result was that stb/ ended up on pin 13, D0 on pin 12,
and so on.
-tony
n the UK) -- the 'TRS-80 Line Printer' (it was nothng of the sort, of
course) -- was a rebadged Cantronics with the obvious parallel
interface. I have the Centronics version here and repair it using the
Radio Shack service manual.
-tony
k in RS232 mode with standard RS232 cables.
Or with a specially wired cable (and RTS asserted from the board) it
works in current loop mode.
I've modified both the boards in my 5155.
-tony
-priority
active sensor to the motor drivers.
You can do an awful lot without microcontrollers.
-tony
rminators. One at each end of the
Unibus, one in the last RK05, RL02 or RK07 on its cable, one in the
last floppy drive on the cable, one at each end of a thinwire ethernet
segment and so on.
[Well, this is classiccmp]
-tony
It's probably still under copyright owned by somebody, but my
experience is that companies don't normally care about 50-year-old
service manuals.
-tony
good starting point?
Interesting, I will take a look.
-tony
something that is very hard to
determine by lookng at the disk but is obviously essential to know to
make use of the diak image.
-tony
read/write at
least one more common cp/m disk type. The hardware should be capable
of it, sure. Doe anyone know if software to do something like this
exists anywhere for the P2000C. I can't find it on any of the obvious
sites
-tony
ommon I/O board in a PERQ2 is the EIO
(Ethernet and Input/Output). There was also OIO (Optional
Input/Output) which provided the 16 bit PERQlink parallel port and a
Canon laser printer interface. Ths led to
'Old McDonald had a PERQ
E-I-O-I-O'
-tony
ould have sex in your code🙂
>
> Hey, when I was in my 20's and programing the 6809 that was fun.
In the UK there was a home computer based on the same Motorola
schematic called the Dragon. Similar to the CoCo, but not identical.
Anyway it was well-known at the time 'You can have SEX with a Dragon'
-tony
On Wed, Dec 4, 2024 at 7:06 PM Nigel Johnson Ham via cctalk
wrote:
[6809]
> I agree. The user stack pointer was a killer feature.
I like(d) the progam counter relative addressing mode along with the
long branch instructions so you could write position-independant code.
-tony
On Wed, Dec 4, 2024 at 6:49 PM Mike Katz wrote:
>
> Tony,
>
> I still say the 6809 was the best 8 bit micro ever.
No dispute from me on that point :-)
>
> Though I don't have any 6809 systems here I still have my 6809/6809E
> Microprocessor Programming Manual from 19
cking?
There's a unit with 12 slots with ball bearings between some of them
to the left of the buttons.. It prevents you pressing more than 1
digit key down at once. That cam cause the levers to stick.
-tony
On Wed, Dec 4, 2024 at 6:24 PM Mike Katz wrote:
>
> Tony,
>
> Thank you for the education. I did some minimal programming of the 6847
> on the CoCo and nothing really on the 6845.
>
> A majority of the 6809 programming that I did was for Gimix, when I
> worked there in t
t could generate the
video addresses and timing (e.g. the Acorn Atom) but didn't have to.
It did handle the data from the video RAM, it had an internal
upper-case only character generator, block graphics, etc. It did
generate colour video.
-tony
On Wed, Dec 4, 2024 at 5:51 PM Tony Duell wrote:
> The schematic in the datasheet I pointed to also shows the ROMs and a
> pair of 6821 PIAs as in the CoCo.
Sorry that never went to the list. The datasheet I refer to is here :
https://archive.org/d
.
That was a rather nice mutliuser OS. I remember at the tme I was
runing OS-9 (initially leval 1 on a 64K CoCo 2, then level 2 on a 512K
CoCo 3) and had to use MS-DOS on a computer at a company I was doing
some work for. The latter felt so primitve by comparison.
-tony
schematic for the 6883 synchronous
address multiplexer chip?
-tony
cuitry as the CoCo.
>
>
> > I found the picture on the front page of this web site humorous. It's a
> > place that sells old Jeep parts. Note the computer surfing the web.
> > https://www.kaiserwillys.com/
-tony
On Sat, Nov 16, 2024, 3:14 PM Jon Elson via cctalk
wrote:
> They SHOULD have started with a clean sheet, of course.
I guess the iAPX 432 wasn't sufficiently "clean sheet" :-)
On Sat, Nov 16, 2024, 3:48 PM Mike Katz wrote:
> The IAPX432 came out the same year that the IBM PC came out which was 3
> years after the 8086
I'm fairly sure design work on the 432 began first.
h
were often recomended as a mains strobe light source 40 years ago.
But having used white LEDs to make a stroboscope flashing 100 or 120
times a second, I will assure you there's enough change in intensity
between 'on' and 'off'' to give a very clear pattern of the strobe
markings even with normal room illumination also on.
-tony
e LEDs are only on for 1/16th of
the time gives a very clear pattern. The bars look sharp and you can
easily see if they are jitterng about due to bad bearings, drive belt
issues, etc.
-tony
hematic but
of course I can't post it here.
If you want to avoid electronics, then stroboscopic tuning fork?
-tony
the order of the decrements and reads was
not specified by the instruction set definition and that on some
machines (the 11/45?) it doubly decrements PC before reading or
storing.
-tony
re the contents of a
string variable as a program line which of course you can then
execute. This is one of the few high level languages I've seen with a
specific instruction for self-modifyng code.
-tony
ry to turn the motor body and
find it sticks and then leaps half a dozen tracks. And when you do up
the clamps, the alignment shifts.
ARGH!
-tony
The IBM TechRef says their 'slimline' drive runs at a
6ms step rate.
I've just stripped and cleaned a pair of the IBM-badged ones (ignore
the Qume manual, there are better ways to do it!). I've had them on an
exerciser and they work reliably at 6ms step rate.
-tony
On Tue, Oct 29, 2024 at 7:00 PM Fred Cisin wrote:
>
> >> 360K drives (40 track) have tracks 48 tpi. (Early on, Shugart SA400, and
> >
> On Tue, 29 Oct 2024, Tony Duell via cctalk wrote:
> > For the pedants, the IBM 360K format is 80 track. 40 cylinders, each
> >
kette will have narrower tracks than normal, which is
> usually not a problem, but the tracks will be at the right spacing.
I've done this many times, mostly to write 40 cylinder CP/M disks on
80 cylinder drives. I use a bulk-erased disk, format and write on the
80 cylinder drive then copy it to a fresh 40 cylinder disk on the
target machine. Never had any problems doing that.
-tony
rives
in my machine (which are both IBM labelled Qumetraks and are slightly
different)
Quite why IBM used 2 different drives from different manufacturers I don't know.
-tony
t seriously a month or so ago to read out
some 1702A EPROMs.
I have a dump of the ROM monitor if you want it, but no other offical
software for the machine.
-tony
ine-drawing characters)
showing where to connect 5 leads from the microtest unit (ground,
index, track 0 sensor, differential outputs of the read amplifier).
You can then do various tests -- spindle speed head alignment, index
position, track 0 sensor position, etc) some of which use the standard
catseye alignment disk.
-tony
7;t put the alignment disk
in.
-tony
Corrected the Subject: line...
On Mon, Sep 23, 2024 at 4:13 PM Glen Slick via cctalk
wrote:
>
> On Mon, Sep 23, 2024, 2:19 AM Tony Duell via cctalk
> wrote:
>
> > Is there are program available that will take an image of a CP/M disk
> > in .IMD format (say) and l
Is there are program available that will take an image of a CP/M disk
in .IMD format (say) and let me view the directory, extract or add
files and so on?
If so, what is recommended and where can I get it?
-tony
On Fri, Aug 2, 2024, 7:52 PM Fred Cisin via cctalk
wrote:
>
> "Legal tender for all debts public or private", but they don't take it!
>
Correct, they don't, so there never was a debt.
On Wed, Jul 31, 2024 at 2:41 PM Maciej W. Rozycki via cctalk <
cctalk@classiccmp.org> wrote:
> On Wed, 31 Jul 2024, CAREY SCHUG via cctalk wrote:
>
> > this is linux, right? so I could have one be kde, one gnome and maybe a
> third xfce? might try playing with it someday, or good if I want to
>
On Tue, Jul 30, 2024, 10:14 PM Jim Brain via cctalk
wrote:
>
> I remember using 3.1, 4.0, and 2000. As I recall, I loved the stability
> of 3.1, but the UI was old and outdated, especially when 95 came out.
> 4.0 offered the nicer UI, but the driver situation was still a problem,
I forget at w
hough finding it might well be a problem, at least
at a sensible price
The title is 'The Differential Analyser' by 'J. Crank'. I have the
1947 edition on my bookshelf, it desribes the non-Meccano machine at
Manchester University with photos and somewhat technical informtion on
how it worked.
-tony
in the London
Science Museum at one time, but I think it's in storage now,
-tony
On Tue, Jul 2, 2024 at 5:28 PM Ali via cctalk wrote:
> > seller.* While some categories are excluded from eIS, there is
> > absolutely positively no reason for US sellers to not sell abroad the
> > majority of categories with it.
>
> Except cost, time, and of course poor tracking. I haven't used
On Tue, Jul 2, 2024 at 2:10 PM Chuck Guzis via cctalk
wrote:
>
> Postal rates between countries have long be determined by treaty. Used
> to be the IPU (International Postal Union), but is now the UPU
> (Universal Postal Union), which is an agency within the UN. The general
> idea is for postal
On Fri, Jun 28, 2024, 10:31 AM Sellam Abraham via cctalk <
cctalk@classiccmp.org> wrote:
> Grow up.
>
There is zero need to get personal. Please stop. Ditto for the earlier
"does not know what he's talking about" comment.
>
On Fri, Jun 28, 2024, 10:18 AM Sellam Abraham via cctalk <
cctalk@classiccmp.org> wrote:
>
> I put the same disclaimer in my listings. However, it is for naught, as
> eBay steps in and applies its own equity based on various factors, so stuff
> can and has been returned with refunds even when the
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