I have a good friend who is a "proper" locksmith, I could ask him if it would
help?
Regards
Rob
On 10 April 2025 19:43:16 GMT+03:00, Tony Duell via cctalk
wrote:
>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 regul
I have been trying to diagnose a video fault on my Rainbow 100A for some
time now. The monitor shows an error message and some of the attributes
displayed are wrong and displayed incorrectly on every line down the screen.
However, the attributes being presented to the DC012 appear to be correct
the code at
0x14D7.
Regards
Rob
> -Original Message-
> From: Rob Jarratt via cctalk
> Sent: 01 January 2025 11:31
> To: 'Warner Losh'
> Cc: 'General Discussion: On-Topic and Off-Topic Posts'
> ; Rob Jarratt
> Subject: [cctalk] R
gards
Rob
From: Warner Losh
Sent: 09 December 2024 18:35
To: r...@jarratt.me.uk
Cc: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: [cctalk] Rainbow Z80 firmware
On Sun, Dec 8, 2024 at 11:58 PM Rob Jarratt mailto:robert.jarr...@ntlworld.com> > wrote:
H
> -Original Message-
> From: jfsebastian--- via cctalk
> Sent: 13 December 2024 01:52
> To: cctalk@classiccmp.org
> Cc: jfsebast...@null.net
> Subject: [cctalk] very old UNIXes software, contact at typewritten?
>
> Hello
>
> I have been doing a several years effort to save (very) old sof
wouldn’t seem possible for it to be able to display this message. Do you still
think it could be one of those two chips?
Thanks
Rob
From: Warner Losh
Sent: 09 December 2024 01:01
To: r...@jarratt.me.uk; General Discussion: On-Topic and Off-Topic Posts
Cc: Rob Jarratt
Subject: Re
Hello everyone,
I am working on a Rainbow 100A which is showing a diagnostic code on the
lights at the back of 0110101. This is supposed to be Message 1 "Main Board
Video".
I have disassembled the 8088 firmware and checked address traces with a
logic analyser and my suspicion is that actual
Not sure of the plugs either but
won't attempt turning on as I don't want to damage the old equipment.
If people are interested in taking it the please make a decent offer. Not
really looking to split it up as I just want it gone.
Based on solihull.
>>
On Fri, 30 Au
Hello Dave,
I am not on FB, any chance you could tell me what terminals they are and
what they are asking for them? Maybe a screenshot if you can fit it on one
page.
Thanks
Rob
> -Original Message-
> From: Dave Wade G4UGM via cctalk
> Sent: 30 August 2024 09:52
> To: General Discussion
> -Original Message-
> From: Paul Flo Williams via cctalk
> Sent: 05 February 2024 16:24
> To: cctalk@classiccmp.org
> Cc: Paul Flo Williams
> Subject: [cctalk] Re: vt220 firmware source?
>
> On Sun, 04 Feb 2024 16:26:57 -0700
> Richard via cctalk wrote:
>
> > In article you
> > wri
> -Original Message-
> From: Paul Koning
> Sent: 05 January 2024 00:34
> To: r...@jarratt.me.uk; cctalk@classiccmp.org
> Cc: Robert Jarratt
> Subject: Re: [cctalk] RIP: Software design pioneer and Pascal creator
Niklaus
> Wirth
>
>
>
> > On Jan
Sad news but a great article Liam, thanks for the interesting history.
The second language I taught myself was Algol 68 (!), on a DECSYSTEM20. I
learned Pascal at University, when I did my M.Sc I used VAX Pascal on a VAX
11/780 and went on to use it as my first professional language. I loved VAX
I think I have got my VT100 basically working now except for the actual
video display. I think there is a problem with the transistor that drives
the flyback transformer. This is Q414 on page 58 of the Feb82 schematic on
BitSavers
(https://bitsavers.org/pdf/dec/terminal/vt100/MP00633_VT100_Schemati
> -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
>
> On Wed, 29 Nov 2023, 'General Discussion: On-Topic and Off-Topic Pos
> -Original Message-
> From: Tony Duell
> Sent: 26 November 2023 06:35
> To: r...@jarratt.me.uk
> Cc: General Discussion: On-Topic and Off-Topic Posts
> Subject: Re: [cctalk] VT100 Monitor Board
>
> On Sat, Nov 25, 2023 at 11:12 PM Rob Jarratt
> wrote:
&g
> -Original Message-
> From: Tony Duell
> Sent: 25 November 2023 14:17
> To: r...@jarratt.me.uk; General Discussion: On-Topic and Off-Topic Posts
>
> Cc: Rob Jarratt
> Subject: Re: [cctalk] VT100 Monitor Board
>
> On Sat, Nov 25, 2023 at 12:07 PM Rob
> -Original Message-
> From: Dave Dunfield via cctalk
> Sent: 25 November 2023 14:06
> To: cctalk@classiccmp.org
> Cc: Dave Dunfield <1297.dunfi...@gmail.com>
> Subject: [cctalk] Re: VT100 Monitor Board
>
> > Rob Jarratt 25 Nov 2023 8:47 a.m.
>
Hello,
As some may recall I have been working on getting a VT100 going again. I
have made good progress and I think the main board is probably OK now (see
here if you are interested:
https://robs-old-computers.com/2023/11/19/vt100-keyboard-constant-clicking-f
ault/). Possibly I still need to re
t take too
long.
On Sun, Oct 8, 2023 at 9:35 AM Rob Jarratt via cctalk mailto:cctalk@classiccmp.org> > wrote:
> -Original Message-
> From: wrco...@wrcooke.net <mailto:wrco...@wrcooke.net> <mailto:wrco...@wrcooke.net> >
> Sent: 08 October 2023 04:15
>
> -Original Message-
> From: wrco...@wrcooke.net
> Sent: 08 October 2023 04:15
> To: r...@jarratt.me.uk; Rob Jarratt via cctalk
> Subject: Re: [cctalk] VT100: Failing 2114 Chip Replaced With One With The
> Same Fault
>
>
>
> > On 10/07/2023 5
I posted recently that I had identified a faulty RAM chip in my VT100 and
having replaced it the terminal seemed to get further into the self test.
After further analysis with the logic analyser I have realised that it is
still failing the RAM test, despite an apparent change in behaviour. I think
I have my faulty VT100 now passing the RAM test, but it is still not
producing any output to the screen. Looking at the DC012 chip it seems to be
permanently asserting the interrupt line and not generating any DMA HOLD
REQUEST signals. It seems that all the clock inputs are running (DOT CLK,
CHAR C
I have a non-functioning VT100. I think it is failing in the POST during the
RAM check. I don't know for sure because I can't get it to light up the LEDs
on the keyboard, however I used my logic analyser (a HP1630G) to see what
values were written to the UART to send to the keyboard and I see it se
level above or below the signal.
5) Trigger mode set to "Auto" as opposed to "Normal" or "Single" causing a
momentary display of the triggered signal which is immediately overwritten by
the current signal.
Tom Hunter
On Mon, Jul 17, 2023 at 1:14 AM Rob Ja
edge trigger, neither of the latter two ever trigger.
Obviously it is my method that is wrong, but I really don't know what it is
about my method that is wrong. Are there any common mistakes that novices make?
Thanks
> -Original Message-
> From: Rob Jarratt
> Sent: 09 July
#x27;t
> > tell me exactly how it works. It isn't completely clear to me if it
> > needs HLDA to be asserted for I/O W to be asserted.
> >
> > > -Original Message-
> > > From: Rob Jarratt via cctalk cctalk@classiccmp.org
> > > Sent: Sunda
-
> From: Rob Jarratt via cctalk
> Sent: Sunday, July 9, 2023 4:39 PM
> To: General Discussion: On-Topic and Off-Topic Posts
>
> Cc: Rob Jarratt
> Subject: [cctalk] VT100: Datasheet for Intel 8228
>
> Hello,
>
>
>
> I have a non-functioning VT100. I think I
Hello,
I have a non-functioning VT100. I think I may have isolated the problem to
an Intel 8228 chip (or 88228, the schematic says 8228, the part is marked
88228C). Certainly, the part gets a bit hot and it doesn't seem to be
outputting anything on the I/O W pin (pin 27) despite activity on STS
Thank you to everyone who helped me with this. The PSU if finally fixed. I have
posted about it on my blog:
https://robs-old-computers.com/2023/06/29/h7842-finally-fixed/
Regards
Rob
> -Original Message-
> From: Rob Jarratt
> Sent: 25 June 2023 18:07
> To:
> -Original Message-
> From: Tony Duell
> Sent: 25 June 2023 18:00
> To: r...@jarratt.me.uk
> Cc: General Discussion: On-Topic and Off-Topic Posts
> ; Brent Hilpert
> Subject: Re: [cctalk] Re: Rainbow H7842 PSU Fault
>
> On Sun, Jun 25, 2023 at 5
Off-Topic Posts
> ; Brent Hilpert
> Subject: Re: [cctalk] Re: Rainbow H7842 PSU Fault
>
> On Sun, Jun 25, 2023 at 5:33 PM Rob Jarratt
> wrote:
> >
> > Thanks Tony. I removed the mains bridge rectifier and found it measured
> short across two of its terminals, so I am
turning.
Regards
Rob
> -Original Message-
> From: Rob Jarratt
> Sent: 25 June 2023 17:34
> To: 'Tony Duell' ; 'r...@jarratt.me.uk'
> ; 'General Discussion: On-Topic and Off-Topic Posts'
>
> Cc: 'Brent Hilpert'
> Subject: RE:
nd Off-Topic Posts
>
> Cc: Brent Hilpert ; Rob Jarratt
>
> Subject: Re: [cctalk] Re: Rainbow H7842 PSU Fault
>
> On Sun, Jun 25, 2023 at 1:36 PM Rob Jarratt via cctalk
> wrote:
> >
> > Hello,
> >
> > It has taken me ages to get back to this, but I
> -Original Message-
> From: Jon Elson via cctalk
> Sent: 25 June 2023 16:24
> To: Rob Jarratt via cctalk
> Cc: Jon Elson
> Subject: [cctalk] Re: Rainbow H7842 PSU Fault
>
> On 6/25/23 07:36, Rob Jarratt via cctalk wrote:
> > This made me suspect th
below.
Regards
Rob
> -Original Message-
> From: Brent Hilpert
> Sent: 26 May 2023 17:24
> To: r...@jarratt.me.uk; General Discussion: On-Topic and Off-Topic Posts
>
> Subject: Re: [cctalk] Rainbow H7842 PSU Fault
>
> On 2023-May-25, at 1:43 PM, Rob Jarratt via cc
> -Original Message-
> From: Peter Coghlan via cctalk
> Sent: 20 May 2023 09:20
> To: 'General Discussion: On-Topic and Off-Topic Posts'
>
> Cc: Peter Coghlan
> Subject: [cctalk] Re: Rainbow H7842 PSU Fault
>
>
>
> Ok, it looks like there is not a severe leak from the -12V line to
> -Original Message-
> From: Peter Coghlan via cctalk
> Sent: 10 May 2023 12:04
> To: 'General Discussion: On-Topic and Off-Topic Posts'
>
> Cc: Peter Coghlan
> Subject: [cctalk] Re: Rainbow H7842 PSU Fault
>
>
> >
> > I will do all the suggested checks, but I won't be able to do th
> -Original Message-
> From: Peter Coghlan via cctalk
> Sent: 09 May 2023 17:58
> To: 'General Discussion: On-Topic and Off-Topic Posts'
>
> Cc: Peter Coghlan
> Subject: [cctalk] Re: Rainbow H7842 PSU Fault
>
> >
> > I am going to read your answer more carefully later. But I wanted t
e -12V line was too high?
>
> (This is a bit unlikely but the 115V/230V switch is set correctly, isn't it?)
>
> On the other other hand, if the manual says that the -12V line is supposed to
> be able to supply 150mA, then it doesn't make sense for the current trip to
>
nderstanding now. I have
noticed a difference here between the good and the bad PSU. On the good PSU I
found the collector on TIP121 at 0V. On the bad PSU it was at +0.016V. The
base-emitter voltage drop is -0.02V on the good PSU and -0.09V on the bad one.
This is making it feel like the TIP121
> -Original Message-
> From: Brent Hilpert
> Sent: 07 May 2023 23:53
> To: r...@jarratt.me.uk; General Discussion: On-Topic and Off-Topic Posts
>
> Subject: Re: [cctalk] Rainbow H7842 PSU Fault
>
> On 2023-May-07, at 1:54 AM, Rob Jarratt via cctalk wrote:
&g
6 of the transformer, but is that
right? Isn’t it the Zener diode half way across the page?
Regards
Rob
From: Rob Jarratt
Sent: 02 May 2023 08:19
To: 'Mattis Lind' ; r...@jarratt.me.uk; 'General
Discussion: On-Topic and Off-Topic Posts'
Subject: RE: [cctalk] R
That’s a good idea, I will try that
From: Mattis Lind
Sent: Tuesday, May 2, 2023 7:55 AM
To: r...@jarratt.me.uk; General Discussion: On-Topic and Off-Topic Posts
Cc: Rob Jarratt
Subject: Re: [cctalk] Re: Rainbow H7842 PSU Fault
Not quite sure what you mean here. I had advice
> -Original Message-
> From: Brent Hilpert via cctalk
> Sent: Monday, May 1, 2023 11:23 PM
> To: General Discussion: On-Topic and Off-Topic Posts
>
> Cc: Brent Hilpert
> Subject: [cctalk] Re: Rainbow H7842 PSU Fault
>
> On 2023-May-01, at 2:25 AM, Peter Coghlan via cctalk wrote:
> >
; From: Rob Jarratt
> Sent: Sunday, April 30, 2023 9:35 PM
> To: 'Wayne S'
> Cc: r...@jarratt.me.uk; 'General Discussion: On-Topic and Off-Topic Posts'
>
> Subject: RE: [cctalk] Re: Rainbow H7842 PSU Fault
>
> Looks like the one I used is an L7812CV, which
n-Topic and Off-Topic Posts
> ; Rob Jarratt
> Subject: Re: [cctalk] Re: Rainbow H7842 PSU Fault
>
> The CT version is 4%, the ACT is 2%.
>
> Sent from my iPhone
>
> > On Apr 30, 2023, at 11:37, Wayne S wrote:
> >
> > Spec sheet for the 7812 shows 2 versions -
I think I have found a possible cause, but not too sure what to do about it
if I have.
I had to replace the 7812 regulator that supplies Vstart. The new one has an
output that seems to vary between 12.2 and 12.4V. The 7812 on the good PSU
outputs a steady 12.1V. I think that is enough to cause the
> It looks like the conditions in the control and overcurrent sensing parts
of the
> working and the non-working PSUs are different so some further
investigation
> may be required as to why this is the case.
>
Yes, that is certainly the problem. Presumably more current is flowing
through the curr
Thanks for the various replies. Here are my responses and further
observations.
I was asked if I had a load on the PSU while bench testing it. The answer to
that is no.
I did check the two diodes around the -12V current sensing resistor (PSU
Sheet 3), but as was pointed out the current sensing re
As some of you may be aware I am trying to find a fault in a Rainbow H7842
PSU. I am using Tony Duell's schematic from here
http://www.bitsavers.org/pdf/dec/rainbow/duell_schematics/psu.pdf.
I have been testing the Control Module by using a bench PSU to supply 15VDC
to the input of the 7812 reg
I wouldn't mind having a copy for completeness too...
> -Original Message-
> From: Hans-Ulrich Hölscher via cctalk
> Sent: 17 March 2023 13:25
> To: General Discussion: On-Topic and Off-Topic Posts
> Cc: Plamen Mihaylov ; Hans-Ulrich
> Hölscher
> Subject: [cctalk] Re: VMS V4.2 MUP (Mand
without desoldering
them, which I would rather avoid. I guess the next step is to replace the
broken parts and use the light bulb current-limiter method to power on the PSU.
Regards
Rob
From: Rob Jarratt
Sent: 24 November 2022 21:45
To: 'Mattis Lind' ; r...@jarratt.me.uk
> -Original Message-
> From: Will Cooke via cctalk
> Sent: 26 November 2022 19:12
> To: Rob Jarratt via cctalk
> Cc: wrco...@wrcooke.net
> Subject: [cctalk] Re: Identifying a Failed Diode in a Rainbow H7842 Power
> Supply
>
>
> I'm not at all famil
t; Rob
> >
> >
> >
> > From: Mattis Lind
> > Sent: 25 November 2022 07:12
> > To: r...@jarratt.me.uk
> > Cc: General Discussion: On-Topic and Off-Topic Posts
> >
> > Subject: Re: [cctalk] Identifying a Failed Diode in a Rainbow H7842
> >
: On-Topic and Off-Topic Posts
Subject: Re: [cctalk] Identifying a Failed Diode in a Rainbow H7842 Power Supply
On 24 Nov 2022, at 22:45, Rob Jarratt mailto:robert.jarr...@ntlworld.com> > wrote:
Thanks for the suggestion Mattis. The UF4007 has a PIV of 1000V, I had a
suggestio
Thanks for the suggestion Mattis. The UF4007 has a PIV of 1000V, I had a
suggestion that the PIV should be 200V. Not sure what rating I should be going
for here?
Regards
Rob
From: Mattis Lind
Sent: 22 November 2022 07:54
To: r...@jarratt.me.uk; General Discussion: On-Topic and Off-T
cctalk
> Sent: 20 November 2022 20:38
> To: Rob Jarratt via cctalk
> Cc: Antonio Carlini
> Subject: [cctalk] Re: Identifying a Failed Diode in a Rainbow H7842 Power
> Supply
>
> On 20/11/2022 17:40, Rob Jarratt via cctalk wrote:
> > The H7842 PSU in my Rainbow failed yesterd
Hello Peter,
Thanks for the analysis. There doesn't seem to be anything further back from
the diode, unless you mean further back behind the inductor?
I will check on the output side as you suggest.
The circuit breaker did pop out when it failed. The onboard fuse is intact.
The house RCD trigger
The H7842 PSU in my Rainbow failed yesterday. At first the machine just
powered down and there was a slight burning smell, I wasn't next to the
machine when this happened, so I didn't see or hear anything to tell me
where the problem might be. Not being sure if there was a short in the
machine or a
Given all the troubles I have had with the H7140 in my PDP 11/24 I am
considering whether to replace it with modern equivalents, installed inside
the H7140 enclosure. I am a bit puzzled by the specs listed in the PDP 11/24
Maintenance Card, it suggests the PSU outputs +12V and -12V from the memory
I have a HP-150 but I am in the UK. I think it would be good to get the images
made and archived before sending the floppies anywhere at all.
Regards
Rob
> -Original Message-
> From: Stan Sieler via cctalk
> Sent: 07 September 2022 01:51
> To: ba...@googlegroups.com; General Discussion
I have just worked out how to dismantle the keycaps, although still
wondering if cleaning them will actually help?
> -Original Message-
> From: Rob Jarratt via cctalk
> Sent: 29 August 2022 11:26
> To: General Discussion: On-Topic and Off-Topic Posts
>
> Cc: Rob
I have a nice HP1630G logic analyser. It still works OK but has a number of
issues that I would like to fix.
First, I managed to break the power switch. It became stiff and wouldn't
readily toggle the power. I think the shaft became bent. In pressing too
hard, I broke off the button on the end
The 11/24 System Technical Manual says that the terminator (M9302 or M9312)
must be installed in the last slot (slot 9) of the backplane, and that all
empty slots must have a grant card. What I am not clear on is what they mean
by an "empty" slot. Specifically, if I have the CPU, the M7134 memory
I am trying to work out why my PDP 11/24 CPU is not working. To do so I want
to use my logic analyser on the F-11 chips. I have a regular 40-pin test
clip, but it doesn't make a good contact with the pins on the F-11 chips.
The test clips I have are made for regular DIP chips where the legs come ou
g
Cc: Rick Murphy
Subject: Re: Replacement for a DEC 7474 Chip
On May 16, 2022, at 4:59 PM, Rob Jarratt via cctalk mailto:cctalk@classiccmp.org> > wrote:
I have several 7474s, including one marked DEC 7474. Sadly, I fear that
shipping from the US is likely to be prohibitive.
> -Original Message-
> From: cctalk On Behalf Of Rick Murphy via
> cctalk
> Sent: 16 May 2022 17:28
> To: cctalk@classiccmp.org
> Subject: Re: Replacement for a DEC 7474 Chip
>
> On 5/15/2022 4:16 AM, Eric Smith via cctalk wrote:
> > On Sat, May 14, 2022, 16:09 ben via cctalk wrote:
>
U Amateur Radio,
> the origin of the open-source concept!
> Skype: TILBURY2591
>
>
> On 2022-05-14 13:48, Paul Koning via cctalk wrote:
> >
> >> On May 14, 2022, at 1:41 PM, John Robertson via
> cctalk wrote:
> >>
> >> On 2022/05/14 10:11 a.m.
Hello,
I have found a bad DEC 7474 chip on my M7133 board. Clearly it is a
7474 D flip flop. The problem is I don't know which modern series
would be the best one to replace it with. I am sure I have seen a list
somewhere of modern equivalents for some DEC chip numbers, but I can't
remember whe
works.
Sorry for the noise.
Regards
Rob
> -Original Message-
> From: Guy Dunphy
> Sent: 01 May 2022 01:22
> To: r...@jarratt.me.uk; Rob Jarratt ; General
> Discussion: On-Topic and Off-Topic Posts
> Subject: Re: Testing a 74S240
>
> At 11:25 PM 30/04/2022
> -Original Message-
> From: cctalk On Behalf Of Chris Zach via
> cctalk
> Sent: 01 May 2022 02:57
> To: CCTalk mailing list
> Subject: Repairing a VT240.
>
> So I'm clearing out projects on my bench. The latest is a Dec VT240 which did
> not work. Has been dead for 20 years, the usua
In trying to fix my M7133 CPU from my 11/24 I thought I had identified a
failed 74S240. However, when I replaced it (while adding a socket), the
fault remained. So, I guess the original chip may not be faulty. I decided
to test the original chip on a breadboard to see if it is OK. This is where
I g
he heat to start to
> transfer! Clean tip and a quick touch with solder is all that is needed.
> When you are not using the iron for some time, but leaving it on, add a
> thicker blob of solder on it so it doesn't get a thin hard to clean oxide on
> it.
> KEEP YOUR TIP FREE
; Rob Jarratt ; General
Discussion: On-Topic and Off-Topic Posts ; Rob Jarratt
via cctalk
Subject: Re: Advice on Desoldering an IC
Cut the pins with a very sharp set of dykes then remove them one at a time.
Then use flux and detailer braid to remove the solder
On April 15, 2022 1:49:33 PM EDT
I am trying to remove an IC from my PDP 11/24 CPU, a DS8641. I am really
struggling to desolder it. I am using the technique of applying fresh solder
and then removing it. But after multiple cycles of this I think I am
starting to damage the PCB.
I am using a fairly cheap desoldering station (t
> -Original Message-
> From: cctalk On Behalf Of Noel Chiappa via
> cctalk
> Sent: 03 April 2022 03:41
> To: cctalk@classiccmp.org
> Cc: j...@mercury.lcs.mit.edu
> Subject: RE: PDP 11/24 - A Step Backwards
>
> > It was quite a struggle to separate those nylon connectors, is there
a
> -Original Message-
> From: cctalk On Behalf Of Rob Jarratt via
> cctalk
> Sent: 02 April 2022 11:58
> To: 'Noel Chiappa' ; 'General Discussion:
On-Topic
> and Off-Topic Posts'
> Subject: RE: PDP 11/24 - A Step Backwards
>
> >
> &
> -Original Message-
> From: Brent Hilpert
> Sent: 31 March 2022 22:48
> To: r...@jarratt.me.uk; General Discussion: On-Topic and Off-Topic Posts
>
> Subject: Re: PDP 11/24 - A Step Backwards
>
> On 2022-Mar-31, at 2:14 PM, Rob Jarratt wrote:
> >> Th
>
> Disconnect the bad ACLO, power it on, and see if the CLK LED comes on. if
> not, then we'll have to work out why not.
This is my plan for later today.
>
> Noel
ned into an
> > actual product. So I'm pretty good with a digital circuit diagram,
> > like these CPU prints. But analog stuff is still a mostly-closed book
> > to me! :-)
> >
> > Anyway, I'm happy to let you provide the analysis of the P/S... :-)
> >
>
> -Original Message-
> From: cctalk On Behalf Of Tony Duell via
> cctalk
> Sent: 31 March 2022 04:26
> To: Noel Chiappa ; General Discussion: On-Topic
> and Off-Topic Posts
> Subject: Re: PDP 11/24 - A Step Backwards
>
> On Thu, Mar 31, 2022 at 3:52 AM Noel Chiappa via cctalk
> wrote
Rob
> -Original Message-
> From: Tony Duell
> Sent: 27 March 2022 10:15
> To: r...@jarratt.me.uk; Rob Jarratt ; General
> Discussion: On-Topic and Off-Topic Posts
> Subject: Re: PDP 11/24 - A Step Backwards
>
> On Sat, Mar 26, 2022 at 9:20 PM Rob Jarratt via cctal
cctalk On Behalf Of Matt Burke via
> cctalk
> Sent: 29 March 2022 01:31
> To: cctalk@classiccmp.org
> Subject: Re: PDP 11/24 - A Step Backwards
>
> On 28/03/2022 23:22, Rob Jarratt via cctalk wrote:
> > Its 600mV, but it is more of a spike than a ripple. Here is a trace:
>
Its 600mV, but it is more of a spike than a ripple. Here is a trace:
https://rjarratt.files.wordpress.com/2022/03/pin-1-5v-ripple.jpg
Regards
Rob
> -Original Message-
> From: Wayne S
> Sent: 28 March 2022 23:15
> To: r...@jarratt.me.uk; Rob Jarratt ; General
> Discussio
> -Original Message-
> From: cctalk On Behalf Of Chris Zach via
> cctalk
> Sent: 28 March 2022 20:57
> To: cctalk@classiccmp.org
> Subject: Re: PDP 11/24 - A Step Backwards
>
> > I don't think the CPU is working at all. The reason being that there
> > is absolutely no LED activity. Inc
> -Original Message-
> From: cctalk On Behalf Of Antonio Carlini
> via cctalk
> Sent: 28 March 2022 07:50
> To: cctalk@classiccmp.org
> Subject: Re: PDP 11/24 - A Step Backwards
>
> On 28/03/2022 04:57, Tony Duell via cctalk wrote:
> >
> > Very little of the stuff I've bought new has h
mpany called Radwell International. Based near me. They succeeded in
getting the PSU to work, which I have been unable to do as it is just beyond me.
>
> On 3/27/2022 2:38 PM, Bill Gunshannon via cctalk wrote:
> > On 3/27/22 05:17, Tony Duell via cctalk wrote:
> >> On Sat, Mar
Thanks for the lengthy reply. Some responses inline below.
> -Original Message-
> From: Noel Chiappa
> Sent: 27 March 2022 21:09
> To: cctalk@classiccmp.org
> Cc: j...@mercury.lcs.mit.edu
> Subject: RE: PDP 11/24 - A Step Backwards
>
> > From: Rob Jarr
> -Original Message-
> From: cctalk On Behalf Of Toby Thain via
> cctalk
> Sent: 26 March 2022 22:07
> To: cctalk@classiccmp.org
> Subject: Re: PDP 11/24 - A Step Backwards
>
> On 2022-03-26 5:20 p.m., Rob Jarratt via cctalk wrote:
> > I had the H7140
I had the H7140 PSU in my PDP 11/24 repaired a little while ago and I posted
about it here: https://robs-old-computers.com/2022/02/10/pdp-11-24-progress/
I have since had the PSU fixed again and it came back a couple of weeks ago.
When I installed it and applied power to the input, I heard a reass
> -Original Message-
> From: cctalk On Behalf Of Fred Cisin via
> cctalk
> Sent: 26 February 2022 20:23
> To: General Discussion: On-Topic and Off-Topic Posts
>
> Subject: Re: Racking a PDP-11/24
>
> > I am not in the USA, but I am should be able to look for other
> > screwdrivers her
ckplane. They are
> intentionally slightly loose in order for the pivot to work. You really
don't
> need, or want, to play with those screws.
Ah! Thanks for that advice.
>
> -Original Message-
> From: Rob Jarratt
> Sent: Saturday, February 26, 2022 3:04 PM
>
> -Original Message-
> From: Paul Koning
> Sent: 26 February 2022 20:14
> To: r...@jarratt.me.uk
> Cc: cctalk@classiccmp.org
> Subject: Re: Racking a PDP-11/24
>
>
>
> > On Feb 26, 2022, at 3:05 PM, Rob Jarratt
> wrote:
> >
> >> .
> -Original Message-
> From: Paul Koning
> Sent: 26 February 2022 19:21
> To: r...@jarratt.me.uk; Robert Jarratt ;
> cctalk@classiccmp.org
> Subject: Re: Racking a PDP-11/24
>
>
>
> > On Feb 26, 2022, at 3:14 AM, Rob Jarratt via cctalk
> wro
Thank you for the reply.
> -Original Message-
> From: pbir...@gmail.com
> Sent: 26 February 2022 08:48
> To: r...@jarratt.me.uk; 'Rob Jarratt' ;
'General
> Discussion: On-Topic and Off-Topic Posts'
> Subject: RE: Racking a PDP-11/24
>
> Th
I am wondering if I have racked my 11/24 correctly.
As you can see here:
https://robs-old-computers.com/2022/02/10/pdp-11-24-progress/ I have put the
CPU at the top and the two RL02 drives underneath.
The problem is that the CPU enclosure catches on the RL02 underneath. There
is a bit of pl
If images don't exist would it be possible to image them and get them on
BitSavers?
> -Original Message-
> From: cctalk On Behalf Of Rod Smallwood
> via cctalk
> Sent: 24 February 2022 08:05
> To: Bill Gunshannon via cctalk
> Subject: 11/83 OS load - problem solved.
>
> Hi
>
> W
alf Of Noel Chiappa via
> cctalk
> Sent: 19 February 2022 09:18
> To: cctalk@classiccmp.org
> Cc: j...@mercury.lcs.mit.edu
> Subject: Re: Is The M9312 Boot Module Essential?
>
> > From: Rob Jarratt
>
> > is the M9312 essential to ever get this ma
?
Regards
Rob
From: Bill Degnan
Sent: 19 February 2022 08:29
To: r...@jarratt.me.uk; Rob Jarratt ; General
Discussion: On-Topic and Off-Topic Posts
Subject: Re: Is The M9312 Boot Module Essential?
You need some way to initialize the system to the peripheral that contains
the.OS media
I have a PDP-11/24. I have never got very far with it because of power
supply problems which I am hopeful will be resolved soon. Looking at the
technical manual, it describes an M9312 bootstrap/terminator module. The
machine did not come with one of these.
I am not sure how the machine could ha
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