>
> >
> >> Found it (on paper): "Generating characters" by Kenneth Perry and
> >> Everett Aho, > Electronics, Jan 3, 1958, pp. 72-75.
> >
> >> Bitsavers has it in the MIT/LincolnLaboratory section:
>
On Friday, December 22, 2023, r.stricklin via cctalk
wrote:
> Did IBM ever publish programming information for their PC SDLC or BiSync
> communications boards? I’m wondering about the possibility of programming
> one to drive the synchronous protocol needed for “booting” a Northstar
> Advantage
efully one or the other useful tape file to discover
>
I actually have all those already. I found them on bitsavers. They have
been tested on the simulator and many of them run well. Several of them are
data tapes which cannot be booted.
/Mattis
>
> Thomas
>
> On 03.12.2023 1
Hello!
I have an ongoing project to restore a Datapoint 2200 version II and in the
process of doing so I created a small simulator for it to understand it
better. The simulator is now in the condition that it runs the cassettes
that I try on it quite well.
The simulator compiles on Macos and
Den tors 30 nov. 2023 kl 11:34 skrev Rob Jarratt via cctalk <
cctalk@classiccmp.org>:
>
>
> > -Original Message-
> > From: Christian Corti via cctalk
> > Sent: 30 November 2023 08:43
> > To: Rob Jarratt via cctalk
> > Cc: Christian Corti
> > Subject: [cctalk] Re: VT100 Monitor Board
>
There have been a number of Ebay listings for various ns32k software, QIC
tapes and 1/2 inch tapes. I thought I would buy them if there were no other
bids to try to recover the contents.
https://www.ebay.com/itm/225759541222
https://www.ebay.com/itm/225759543101
Den tis 29 aug. 2023 kl 13:30 skrev Chris Zach via cctalk <
cctalk@classiccmp.org>:
> Oh baloney. As long as the backplane pins are not mushed these are
> surprisingly easy to fix and mouse crap can be vacuumed out and cleaned
> off the cards and pins.
>
> The thing that drove me the most nuts
Den tors 27 juli 2023 kl 17:12 skrev Paul Koning via cctalk <
cctalk@classiccmp.org>:
>
>
> > On Jul 27, 2023, at 11:08 AM, Chris Zach via cctalk <
> cctalk@classiccmp.org> wrote:
> >
> > Yah. One problem with me is that I have the detail skills of a gopher.
> So I'm not the best person to try
already did such a great effort to
dump all these disks I would kindly ask you to just take a photo of each of
them so other people could use them easily.
Thanks,
Mattis Lind
>
>
> MicroRSX, Ultrix11, MicroRSTS/E, and um spss
>
> On 7/26/2023 1:51 PM, Mark Matlock via cctalk wrote:
Great work!
Can I ask you to snap a photo of each disk and store it along with the
IMD-files with the same name but a JPG extension? It greatly helps when
trying to use the disk-images to have this kind of meta information.
Thanks,
/Mattis
Den mån 15 maj 2023 kl 08:04 skrev Chris Zach via
>
>
> Not quite sure what you mean here. I had advice from a friend to bench test
> the control module by providing 14V to the input of the 7812. On the good
> PSU I can see the PWM operate, on the bad one the PWM is shutdown.
>
And what happens if you feed in exactly 12 V on the output of the
Den sön 23 apr. 2023 kl 08:34 skrev Christopher Zach via cctalk <
cctalk@classiccmp.org>:
> Not that I know of. Esdi has a much faster data rate and I think that
> outstrips the BBB solution.
>
Not necessarily. Yes, data rates are faster in ESDI. Up to 24 MHz and
perhaps higher. But in ESDI
That is a BA11-M box with a H780 supply. The schematics can be found in the
KC780 document since the front end processor of the 11/780 is a PDP-11/03
with a RX01 drive.
In the end of this document there is a schematic:
http://bitsavers.org/pdf/dec/vax/780/MP00534_KC780_Nov77.pdf
Good luck!
>
> > I have an Ampro Little Board Plus, which is a single-board Z80 computer
> the size of a 5 1/4" disk drive. The "plus" means it has a SCSI
> interface. A couple of years ago I was planning to build a flash disk for
> it and dug through a lot of specs and bios code. Original SCSI was almost
input. Remove any scope probes…
/Mattis
>
> Regards
>
> Rob
>
> From: Rob Jarratt
> Sent: 24 November 2022 21:45
> To: 'Mattis Lind' ; r...@jarratt.me.uk; 'General
> Discussion: On-Topic and Off-Topic Posts'
> Subject: RE: [cctalk] Identifying a
> Regards
>
> Rob
>
> From: Mattis Lind
> Sent: 22 November 2022 07:54
> To: r...@jarratt.me.uk; General Discussion: On-Topic and Off-Topic Posts
>
> Subject: Re: [cctalk] Identifying a Failed Diode in a Rainbow H7842 Power
> Supply
>
>
> Hello Rob!
Hello Rob!
>
> Given that before the transistor blew up there had clearly been another
> failure somewhere else, I tried to find the original failure. There were no
> obviously damaged parts, so I just probed around near the transistor for
> any
> parts that were open circuit or short circuit. I
What about the M9300 board? Do you have an idea what the purpose is of that
card? It look a bit like a M9302 but with more logic on it and a few
jumpers and a LED. It also have a delay line and a monostable flip-flop.
Here is a photo of a (dusty) M9300:
The guys at RICM have seen a problem with these supplies that if the output
cap is bad it won't start switching properly. It goes into a mode where it
acts as a linear regulator. As far as I remember they the a spice
simulation that also indicated this when the output cap had low
capacitance.
Do
>
> Well, both the SF-7000 as well as the SF-6500 (the size for QIC
> cartridges) are de facto unavailable/out of stock/whatever.
> The only alternative that I could find are the Mobilon Bands from
> Nisshinbo. But same story, I can't order them, there is no store that I
> could do that.
>
Have
Den tors 30 dec. 2021 kl 19:08 skrev Rob Jarratt via cctalk <
cctalk@classiccmp.org>:
> Hello All,
>
>
>
> Following a discussion on resurrecting a PDP 11/45 I have started looking
> at
> the regulator bricks in the PSU. I have started with a H744. I reformed the
> three big capacitors, although
Den lör 12 juni 2021 kl 10:54 skrev Christian Corti via cctalk <
cctalk@classiccmp.org>:
> On Fri, 11 Jun 2021, Santo Nucifora wrote:
> > I am currently working on an IBM 5100 that has some issues. I know for
> > certain that the 5100 has a bad graphics controller card so I need to dig
> > into
Today I finally got the SPACEWAR version for PDP-11/10 running again on my
PDP-11/05 with AR11 board. I played a couple of rounds together with my
daughter. She was better than me. Quite hard game IMHO.
https://youtu.be/fTiHRAKjyho
Bill Seiler and Larry Bryant wrote this version in 1974 and
from what they used in the PDP-8 and PDP-9 schematics while
still using the older transistor modules rather than TTL in the RF08/RS08.
The schematics are dated around 1970.
/Mattis
fredag 30 april 2021 skrev Josh Dersch :
>
>
> On Fri, Apr 30, 2021 at 2:24 PM Mattis Lind wrote:
>
>
I did another check of the drawings and found a module list.
Initially I was looking for something more graphic then I found this:
https://imgur.com/a/hzmhwQ4
Hope it helps.
/Mattis
söndag 25 april 2021 skrev Josh Dersch :
>
>
> On Sun, Apr 25, 2021 at 1:55 PM Mattis Li
of the drawings didn’t reveal any module placement drawing. I
will check in more detail tomorrow.
/Mattis
söndag 25 april 2021 skrev Josh Dersch :
>
>
> On Sun, Apr 25, 2021 at 1:55 PM Mattis Lind wrote:
>
>>
>>
>> Den sön 25 apr. 2021 kl 22:43 skrev Josh Dersch via cct
Den sön 25 apr. 2021 kl 22:43 skrev Josh Dersch via cctalk <
cctalk@classiccmp.org>:
> Hi all --
>
> In addition to the 11/45 project I'm also working on restoring an RF08/RS08
> fixed head disk/controller (in the vain hopes of one day running TSS/8 on
> my PDP-8/I). I have the power supply
Den tors 4 mars 2021 kl 08:06 skrev Marc Howard via cctalk <
cctalk@classiccmp.org>:
> Does anyone out there have a "1" key (the one in the numeric keypad, not
> the 1 / ! key) that they are willing to sell: me? I saw a couple of
> partial keyboards go fairly cheap on ePay a couple of months ago
onsdag 24 februari 2021 skrev Chris Zach via cctalk :
> They are RT11/TSX versions.
>
> Now for the problem of the day. The TSX 5.1 distribution have damage to
> track zero, my guess is they were in the Solarex drives where the wonderful
> silicon dust did a job on them. Anyone got really good 8
Den ons 24 feb. 2021 kl 04:57 skrev Ethan Dicks via cctalk <
cctalk@classiccmp.org>:
> On Tue, Feb 23, 2021 at 9:53 PM Chris Zach via cctalk
> wrote:
> > Wow, I've always wanted an 11/750. Not sure why, the small box size is
> > impressive and all that.
>
> I started on an 11/750 in 1984. They
Den tis 16 feb. 2021 kl 19:04 skrev Chuck Guzis via cctalk <
cctalk@classiccmp.org>:
> Building floppy controllers from MSI TTL was not uncommon, even after
> the debut of the WDC LSI chips, which were initially very expensive.
>
I got information from a person that worked for Q1 reseller in
ntral.org/technology/
>
>
> Sorry, NO technical details of the controller that he designed.
>
>
> On Mon, 15 Feb 2021, Mattis Lind wrote:
> > Well. Now this is NOT a standard 179x that has written this. As I
> mentioned
> > early on in this thread it was n
Den mån 15 feb. 2021 kl 20:51 skrev Fred Cisin via cctalk <
cctalk@classiccmp.org>:
> On Mon, 15 Feb 2021, Mattis Lind via cctalk wrote:
> > My guess is that the data that follows the sector ID is some kind of
> > checksum.
>
> yes. well, sorta. 16 bit CRC
>
>
&g
? Is it PL/1?
It seems like a record on the disk is a line!
Den mån 15 feb. 2021 kl 18:08 skrev Mattis Lind :
> I did some more research into this and found that a pattern 0x55509255 for
> Address mark and 0x55509251 for Data mark could be used to match against
> the incoming synchronized da
. Including these also makes sense
because then the Track and sector will end up on proper 8 bit boundaries.
/Mattis
Den lör 13 feb. 2021 kl 21:51 skrev Mattis Lind :
>
>
> Den lör 13 feb. 2021 kl 21:06 skrev Chuck Guzis :
>
>> On 2/13/21 11:15 AM, Mattis Lind wrote:
>>
&
Den lör 13 feb. 2021 kl 21:06 skrev Chuck Guzis :
> On 2/13/21 11:15 AM, Mattis Lind wrote:
>
> > As to the 8x/5xH intervals, they appear to be part of the
> > preamble to address marks.
> >
> >
> > Can you please elaborate! What do you mean by
Den lör 13 feb. 2021 kl 19:45 skrev Chuck Guzis via cctalk <
cctalk@classiccmp.org>:
> On 2/13/21 9:18 AM, Mattis Lind via cctalk wrote:
>
>
> > Link contains histogram files and a raw track flux file.
> >
> >
> https://drive.google.com/drive/folders/1URC5i8As
Den lör 13 feb. 2021 kl 18:40 skrev Jon Elson :
> On 02/13/2021 11:18 AM, Mattis Lind via cctalk wrote:
> > The longest flux lengths are interspersed in between more normal flux
> > lengths in the actual data and I get the same type of result regardless
> of
> >
I have a few 8 inch floppy disks coming from a Q1 Lite computer. I tried
reading them on a PC with a Adaptec 1522A floppy controller but it failed
completely.
Then I tried my Catweasel and dumped the raw flux data. The format differs
from what I have seen before.
I did a quick histogram of the
I am pretty sure that my controller is the IBM Enhanced ESDI board and
having support for it in Linux is probably unlikely. But perhaps it is the
WD1007, I am not sure until I checked and it is 100 km away right now.
Anyway I did some reading of the ESDI spec. There are things that I really
like
Den tors 11 feb. 2021 kl 20:36 skrev Fred Cisin via cctalk <
cctalk@classiccmp.org>:
> On Thu, 11 Feb 2021, Mattis Lind via cctalk wrote:
> > What is the best way of dumping the contents of an ESDI disk?
>
> Same as for ST506/412
>
I usually use David Gessweins MFM emul
Den tors 11 feb. 2021 kl 19:05 skrev Al Kossow via cctalk <
cctalk@classiccmp.org>:
> On 2/11/21 9:25 AM, Mattis Lind via cctalk wrote:
>
> > I have an original IBM Enhanced ESDI ISA controller board. Could that be
> > used under Linux?
>
> It's unlikely an
What is the best way of dumping the contents of an ESDI disk?
I have an original IBM Enhanced ESDI ISA controller board. Could that be
used under Linux? Or NetBSD/FreeNSD? I googled but didn't find much.
Is there any other way of dumping the disk contents?
In theory it should be just a matter
Den mån 8 feb. 2021 kl 20:39 skrev David Schmidt via cctech <
cct...@classiccmp.org>:
> On 2/8/21 1:00 PM, Mattis Lind wrote:
>
> I wrote my own, not knowing where another one lived. I happen to think
> in Java, so that's what it's implemented in.
>
> Description is here
This is highly annoying. Back in 2015 I did exactly this and now I have
forgotten how.
I dumped a set of RX02 disks with catweasel into .DMK and now I want a raw
sector image to be able to test them with SimH.
What is a good tool to use? I have some faint memory of glancing through
hexdumps of
Den ons 3 feb. 2021 kl 18:55 skrev Al Kossow via cctalk <
cctalk@classiccmp.org>:
> On 2/3/21 9:43 AM, Paul Koning via cctalk wrote:
>
> > A nice benefit of capturing the raw waveforms and post-processing them
> is that you can do all sorts of very complex processing. If the media are
> nice and
Den ons 3 feb. 2021 kl 18:00 skrev Chuck Guzis via cctalk <
cctalk@classiccmp.org>:
> On 2/3/21 7:14 AM, dwight via cctalk wrote:
> > I'm curious as to how the sampling code looks. Do you use the timers?
> > Dwight
>
> Exactly. You run the sample timer in "capture" mode using DMA. There's
> a
Den ons 3 feb. 2021 kl 15:07 skrev Paul Koning via cctalk <
cctalk@classiccmp.org>:
>
>
> > On Feb 3, 2021, at 2:51 AM, Peter Corlett via cctalk <
> cctalk@classiccmp.org> wrote:
> >
> > On Tue, Feb 02, 2021 at 09:20:01AM -0800, Chuck Guzis via cctalk wrote:
> > [...]
> >> When I last proposed
Den ons 3 feb. 2021 kl 13:25 skrev Al Kossow via cctalk <
cctalk@classiccmp.org>:
> On 2/2/21 11:51 PM, Peter Corlett via cctalk wrote:
>
> > I have a pile of Blue Pill boards, and using it to read floppies was an
> > obvious application. However after running the numbers, it turned out
> there
>
> Uh, I think over the decades, I've contributed a bit, no? I recently
> made my own Catweasel source code public, for example. I've helped out
> the guy with the fluxengine puzzle out a couple of formats, including
> the Brother 240K one that few seem to have sussed out.
>
I am still using a
I have found this catalogue useful to browse when trying to find the
appropriate housings and pins.
https://www.te.com/commerce/DocumentDelivery/DDEController?Action=srchrtrv=82181_SOFT_SHELL_CATALOG=CS=EN
It covers both the commercial Mate-n-lok used in the PDP-11 and universal
Mate-n-lok used
Den tis 26 jan. 2021 kl 22:39 skrev Paul Koning :
>
>
> > On Jan 26, 2021, at 2:35 PM, Mattis Lind wrote:
> >
> >
> > Hello Paul,
> >
> > ...
> >
> >> The framing is different but no harder, I think. And I was thinking of
> leaving th
Den ons 27 jan. 2021 kl 06:59 skrev Tom Uban via cctalk <
cctalk@classiccmp.org>:
> Are the power connectors on the DEC PDP-11 backplanes (e.g. DD11-DF 15pin
> and 6pin) Molex or other?
> Are they still commonly available?
>
They are called Commercial Mate-n-lok. Company is called
Hello Paul,
>
> Mattis, thanks! That's an implementation along the lines I was thinking.
> If yours can get close to 1 Mb/s, chances are one could get all the way
> there with the Arduino Itsy Bitsy M4, that's a 120 MHz ARM chip (Cortex
> M4). It has USB built-in. I'll study your code; that
I did a thing called SyncDongle.(
https://github.com/MattisLind/alfaskop_emu/tree/master/hardware/SyncDongle)
Essentially a BluePill with some level converters. It is using the SPI port
for sync communication.
Then I developed a BSC implementation and a HDLC implementation to use on
the
Den mån 18 jan. 2021 kl 19:55 skrev Chris Zach via cctalk <
cctalk@classiccmp.org>:
> Found more stuff. 4 Perq boards, the HP1000, a Perq mouse and "pad", a
> Sun4 keyboard with 15 pin plug, and another Perq2 keyboard. Also found a
> weird one, a MFM drive with an adapter board on the bottom. Is
torsdag 14 januari 2021 skrev Paul Koning via cctalk :
>
>
> > On Jan 14, 2021, at 1:42 PM, Chris Zach wrote:
> >
> > ...
> > Is there a hardware emulator that can emulate RX50's from images to a
> Pro? Been wondering that...
As far as the releasnotes tell FlashFloppy by Keir Fraser support
POS onto the hard disk.
so there is some PERQ stuff there at least.
>
> http://www.pdp8online.com/rd53/rd53.shtml
>
> Shim picture.
> http://www.pdp8online.com/rd53/pics/lock.shtml?small
>
>
> On Sat, Jan 02, 2021 at 02:05:11PM +0100, Mattis Lind wrote:
> &
ound like full seeks but rather quite short. The drive kept doing
this for maybe one minute and then spun down.
/Mattis
>
>
>
> On Sat, Jan 02, 2021 at 02:05:11PM +0100, Mattis Lind wrote:
> > Den l?r 2 jan. 2021 kl 11:48 skrev Rob Jarratt <
> robert.jarr...@ntlworl
I used the Davids MFM emulator to emulate an RQDX2 formatted disk a few
years ago. I tested both with a RQDX1 and RQDX2. Both were tested with
10.0D firmware. I know that we had some initial problems which David fixed
quickly. As far as I remember I did read disks as well. But I have no
traces of
Worked a bit more with this drive.
Removed the PCB and found the combined brake and head lock solenoid. It
operated freely. As I couldn't find any way of observing the head
positioning mechanism from the outside I opened the lid of the drive. With
the solenoid in the unlocked position it was
k spindle motor
>
> Then again the Diablo 44 is always running the fan but I haven't found a
> source of air filters for that yet (unlike the RL02).
>
Actually I am not counting on this drive to live forever. I just want to
make an image of it and then probably replace it with something
? What resolutions are there to this type of problem?
/Mattis
>
> Regards
>
> Rob
>
> > -Original Message-
> > From: cctalk On Behalf Of Mattis Lind
> via
> > cctalk
> > Sent: 02 January 2021 08:59
> > To: General Discussion: On-Topic and Off-Topic P
I have a nice ICL PERQ 2 T2 that I am going to start working with now.
First thing was to try to image the hard drive. It is a Micropolis 1303. It
spins up but when it reaches what I think the correct speed it immediately
spins down. Usually I think there would be a click and then the heads would
I found a three RX01 disk set for a Fortran IV system V2.5 for RT-11.
I dumped the contents and it is available here:
https://drive.google.com/file/d/12VXh4wk3Zo_fSGRtLPHwrJg6ui3pwVd-/view?usp=sharing
I dumped almost 50 TU58 tapes. They were given to me by an ex DEC FS
engineer.
Most of them are various 11/750 diagnostics. The tapes or not the official
DEC TU58 tapes but home brewed tapes used in FS so there might not be an
exact match to existing lists of official tapes. But they might be
Den mån 16 nov. 2020 kl 05:34 skrev Mike Douglas via cctalk <
cctalk@classiccmp.org>:
> I’ve got some adhesive backed industrial felt that I punch with a leather
> punch. I’ve replaced many of those pads on 8” and 5.25” drives and the felt
> pad works well. Shoot me an email and I can send you a
Does anyone have some good hints on what and how to replace them?
I have a CDC 8 inch floppy drive with a missing pressure pad. Tried to put
some half a millimeter felt cloth with some double adhesive tape to replace
it.
But it didn't work very well. If I gently pushed the upper pressure pad arm
Den lör 10 okt. 2020 kl 13:23 skrev Stefan Skoglund via cctalk <
cctalk@classiccmp.org>:
> ons 2020-10-07 klockan 14:08 -0400 skrev Paul Koning via cctalk:
> >
> > Not flags, that's an HDLC concept. Bisync uses sync characters (as
> > DDCMP does) but instead of doing framing by byte counts it
Den ons 7 okt. 2020 kl 22:19 skrev Peter Coghlan via cctalk <
cctalk@classiccmp.org>:
>
>
> However, I know of at least two projects which implement bisync line to
> TCP/IP gateways to interface to IBM terminals using additional hardware.
> Perhaps it might be possible to adapt one or both to do
I am helping a friend with his IBM 3279 terminal. I got the PSU working
after reverse engineering it. Concluded that the SMPS control chip was a
standard TDA 2640 in IBM disguise.
But of course the thing didn't work with the PSU fixed. A fuse which was in
series with the vertical deflection coil
Den ons 30 sep. 2020 kl 08:26 skrev Josh Dersch via cctalk <
cctalk@classiccmp.org>:
> Hi all --
>
> This is a long shot, but I was curious if anyone might have information on
> the Motorola MDP-1000 minicomputer. I picked one up recently and I'm
> working on restoring it. Of particular
Hello Paul,
Den ons 2 sep. 2020 kl 15:54 skrev Paul Birkel :
> Mattis: Is that SDLC implementation generally available? I see some
> interesting discussion of the possibility on Stack Exchange (Uriel Katz),
> but no obvious reference to a repository.
>
It is here:
I have been working on a project for some time to connect a IBM3270
compatible Alfaskop terminal with its IBM 3274 compatible cluster
controller to the Hercules mainframe emulator.
Yesterday I eventually succeeded. I was able to login to TSO on my Hercules
system that ran MVS 3.8j.
Here are a
A company has a few VME SUN 3/xxx CPU Cards and a SMD card for sale in case
anyone is interested:
https://ggsp.se/69-oevriga
Approximately 100 USD each.
They have also been listed on Swedish auction site Tradera for some time
without selling so perhaps it is possible to negotiate?
/Mattis
I just happen to see this auction:
https://www.liveauctioneers.com/item/86804138_entrex-480-vintage-computer-electronics-lot
Looks like three systems. One marked Entrex 480 the others look like the DG
Nova clone DCC 116. On top there seems to be a Diablo printer of some sort.
Some rust, indeed.
lördag 20 juni 2020 skrev Al Kossow via cctalk :
> On 6/20/20 2:36 AM, Mattis Lind via cctalk wrote:
>
> If anyone has a type 1 3174 that does BSC and SDLC so I could test my stuff
>> I would be very interested.
>>
>
> Dave Wade just posted that he had some
Hello!
I have been working on interfacing the Hercules emulator with various real
terminals for some time. First project was an Alfaskop terminal cluster
which I connected using a small STM32 controller handling BSC.
Next is an Informer 213, portable 3178/3174 compatible terminal. It it
using
> The T11 is not halted - it's looping endlessly in the first ROM. There is
> a brief burst of DRAM select activity on the scope just before it hangs in
> the loop.
>
That burst of DRAM activity might indicate a DRAM problem. One thing I
have tried in the past is to put a known good DRAM on top
>
>
>
> Now that you know the T11 is good I think it a good idea to attach a logic
> analyzer on the bus.
>
> I would then disassemble the ROM code and match that with the logic
> analyzer execution trace. Then it should be possible to find out what is
> going on. If one can rely on the fault code
torsdag 11 juni 2020 skrev Charles via cctalk :
>
> On 6/10/20 4:31 PM, Jon Elson wrote:
>
>> On 06/10/2020 12:48 PM, Charles via cctalk wrote:
>>
>>>
>>> That leaves the unlikely possibility that one of the octal TTL devices,
>>> or ROMs. has developed a weird internal pathway that only
Is there anyone that has already built a tool to dump TU58-tapes on a Linux
machine? I have the drive of course.
There is PUTR. But it is DOS only and is written in assembler so it cannot
be ported easily. The other option is running RT11 on a PDP-11, but then
there is the hassle of getting the
Den tis 9 juni 2020 kl 19:04 skrev Ethan Dicks via cctalk <
cctalk@classiccmp.org>:
> On Tue, Jun 9, 2020 at 10:46 AM Jon Elson via cctalk
> wrote:
> > On 06/09/2020 09:27 AM, Anders Nelson via cctalk wrote:
> > > Related question: Is there any reason, other than historical accuracy
> and
> > >
Preferably OS/VS2 TCAM System Programmer's Guide TCAM Level 10. GC30-2051
but I think it is similar to OS/VS2 TCAM Programmer's Guide, GC30-2041.
I get a hit for the former one:
http://www.computinghistory.org.uk/det/9844/OS-VS-TCAM-Progarmmer-s-Guide-TCAM-Level-10/
But it is not online.
Any
sensing resistor R73 and see if it is
a proper ramp as it should.
What about the R92 linearity potentiometer. Is it ok? Diode D31? Actually
check all semiconductors.
/Mattis
måndag 20 april 2020 skrev Mattis Lind :
>
>
>
>>
>>
>> Something else that might help with d
>
>
> Something else that might help with diagnosis is taking pictures of the
> screen with known, simple elements on the screen.
> e.g.:
> - clear the screen
> - take pic if it doesn't clear
> - type a simple character like a "-"or "1"
> - pic
> - type a
måndag 20 april 2020 skrev Chris Zach via cctalk :
> As I wrote earlier in the thread I think it is a good idea to check the V
>> sync and H sync signals to check that they are right in pulse length and
>> shape.
>>
>
> Good starting point. From the schematics would that be scope probe to J1
>
Den sön 19 apr. 2020 kl 17:22 skrev Jon Elson :
> After looking at the video, and Mattis' description of the
> sweep method, I'm guessing a counter
> in the chain has gone bad. Assuming this uses a 5 x 7
> character matrix, then there would be probably
> a divide by 6 for the scan across each
söndag 19 april 2020 skrev Chris Zach via cctalk :
> Well, let's see: I took the bottom off the VT52 and checked the
> connections to the high voltage board on the back. Cleaned up both
> connectors, plugged in, same problem.
>
> I do hear a medium to high pitched squeal coming from the back
t; Warner
>
>
>>
>> C
>>
>> On 4/18/2020 4:45 AM, Mattis Lind wrote:
>> > Hello Chris!
>> >
>> > Sorry that your trusty VT52 failed. But it shouldn't be too hard to
>> > repair it!
>> >
>> > I have successfully re
; C
>
> On 4/18/2020 4:45 AM, Mattis Lind wrote:
>
>> Hello Chris!
>>
>> Sorry that your trusty VT52 failed. But it shouldn't be too hard to
>> repair it!
>>
>> I have successfully restored a VT52 (actually a VT50 with a brain
>> t
>
>
> One approach to testing flyback transformers seems to be to use a circuit
> that causes them to ring and observing whether the ringing is damped by
> shorted turns. I've never got around to trying this myself.
>
>
I have a VT100 that failed with some smoke coming out of the center of the
Den lör 18 apr. 2020 kl 13:26 skrev Rob Jarratt via cctalk <
cctalk@classiccmp.org>:
> Some of you may recall seeing me post about the VAXmate PSU failure. Thanks
> to members of this list I found the failed part in the PSU and the PSU is
> now working again. However, it looks like the PSU failed
Hello Chris!
Sorry that your trusty VT52 failed. But it shouldn't be too hard to repair
it!
I have successfully restored a VT52 (actually a VT50 with a brain
transplant): http://www.datormuseum.se/home/dec-vt5x. My experience is that
the capacitors were in good shape. Especially the bigger
söndag 12 april 2020 skrev Rob Jarratt via cctalk :
> This machine acts oddly. After powering it off, you usually can't power it
> back on again for about 30 seconds or so, it just seems to ignore the power
> switch. Similarly, if it has been switched off at the front power switch,
> it
> will
>
>
> I have found the problem and a possible other problem too.
>
But that is great!
>
> I have discovered that D24 is shorted (no visible damage), although its
> twin D23 is not. I will replace both. I know it is shorted because I lifted
> one end.
>
Well, sometime there are no visible damage
difference, the result was identical.
>
>
You can loose detail since the sampling rate is a function of sweep
frequency/ time base setting.
>
>
> Regards
>
>
>
> Rob
>
>
>
> *From:* Mattis Lind
> *Sent:* 09 April 2020 05:52
> *To:* r...@jarratt.me.uk; Gener
a faster timebase. 5 or 10 microseconds. Find
out if you can trigger on something that happen only when it stops. Like
channel 2 negative slope.
/Mattis
>
>
> Thanks
>
>
>
> Rob
>
>
>
> *From:* Mattis Lind
> *Sent:* 08 April 2020 07:42
> *To:* r...@j
Den ons 8 apr. 2020 kl 00:34 skrev Rob Jarratt via cctalk <
cctalk@classiccmp.org>:
>
>
> > -Original Message-
> > From: cctalk On Behalf Of Brent Hilpert
> via
> > cctalk
> > Sent: 06 April 2020 21:07
> > To: General Discussion: On-Topic and Off-Topic Posts
>
> > Subject: Re: VAXmate
Den sön 5 apr. 2020 kl 23:53 skrev Rob Jarratt via cctalk <
cctalk@classiccmp.org>:
>
>
> > -Original Message-
> > From: cctalk On Behalf Of Brent Hilpert
> via
> > cctalk
> > Sent: 05 April 2020 21:18
> > To: Rob Jarratt ; General Discussion:
> On-Topic
> > and Off-Topic Posts
> >
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