which iss drive the 10 plotter 20 meg one? Ed#
In a message dated 3/27/2020 5:12:08 AM US Mountain Standard Time,
cctalk@classiccmp.org writes:
On 3/27/20 3:55 AM, P Gebhardt via cctalk wrote:
> I contacted two times Al via email for access credentials to upload the
> document as I did
Diane,
Very nicely done. I read the whole thing.
GOD Bless and Thanks,
rich!
On 3/29/2020 3:59 PM, Diane Bruce via cctech wrote:
On Mon, Mar 30, 2020 at 09:47:51AM +1300, Brendan McNeill via cctech wrote:
Here in NZ and around the world many of us are in lockdown and spending more time on
Remembering that I have the R400x enclosure and I'm only interested in
powering disk drives - I looked up the specs for the RF7x drives, and they all
use about 1.5A at 5V and 2.5-3A operating at 12V. There's a 5-6A spinup surge
on the 12V supply, but as long as you spin them up in sequence
Nigel,
I first learned assembly on a straight-8. Also learned about repair with
the same machine (1974).
As for fun time wasters back then there was a DECUS paper tape that could
compute n! up to 200! exactly. I remember that I could start it before
lunch, come back, and then about 15 minutes
>
> Since I am forced to stay at home more than I would like I though I would
> check some more PSUs. One I wanted to check was the H7109-C from one of my
> VAXstation 4000 VLC machines. I found a leaked capacitor and some other high
> ESR ones, so I will replace those. However, I also noticed a
On Sun, Mar 29, 2020, 5:10 PM Diane Bruce via cctalk
wrote:
> On Sun, Mar 29, 2020 at 05:59:42PM -0400, Nigel Johnson via cctalk wrote:
> > Brings back memories! My first 6800 cross assembler came to me as 2000
> > Fortran source code punch cards. We had an F4R4 compiler on the PDP11 but
> >
I can't be the only one who would like to see the FORTRAN source of some of
those editors, linkers, macro processors.
As a medical electronics guy, I had to deal with a fortran monster of a
database engine, manman.
It was legacy in with the FDA, but woa, what a suck piece of crap it is.
Hi
On Sun, Mar 29, 2020 at 05:59:42PM -0400, Nigel Johnson via cctalk wrote:
> Brings back memories! My first 6800 cross assembler came to me as 2000
> Fortran source code punch cards. We had an F4R4 compiler on the PDP11 but
> the card reader was on the PDP-8.
Funny how the kids don't realise
Since I am forced to stay at home more than I would like I though I would
check some more PSUs. One I wanted to check was the H7109-C from one of my
VAXstation 4000 VLC machines. I found a leaked capacitor and some other high
ESR ones, so I will replace those. However, I also noticed a ceramic
Brings back memories! My first 6800 cross assembler came to me as 2000
Fortran source code punch cards. We had an F4R4 compiler on the PDP11
but the card reader was on the PDP-8.
The only common peripheral was paper tape. One night, the Chief
Engineer and I fed the cards into the PDP8 card
I have some notes I made about trying a PC PSU, I don't think it really worked,
there are signals to indicate power OK and perhaps others. But perhaps a more
concerted effort might yield something that could work.
Regards
Rob
> -Original Message-
> From: cctech On Behalf Of Robert
>
I forgot to mention that I replaced a fair number of capacitors, even ones that
had not leaked, because their ESR was a bit suspect. I have some notes, but it
is hard to reconstruct exactly what I did.
Regards
Rob
> -Original Message-
> From: cctech On Behalf Of Maciej W.
> Rozycki
Here in NZ and around the world many of us are in lockdown and spending more
time on our computers, if that were possible. I have just completed the
restoration of a PDP-8 Straight 8 which I believe is the only one in New
Zealand. You can view the restoration story and find appropriate
On Mon, Mar 30, 2020 at 09:47:51AM +1300, Brendan McNeill via cctech wrote:
> Here in NZ and around the world many of us are in lockdown and spending more
> time on our computers, if that were possible. I have just completed the
> restoration of a PDP-8 Straight 8 which I believe is the only
>Maciej W. Rozycki wrote:
>numerous Chemi-Con SXF parts scattered across
>all boards, some leaking
Yeah, mine is full of "Nippon Chemi-Con" electrolytic too.
What about just gutting the PS chassis and sticking in an ATX power supply?
I don't know how the maximum current per output
> On Mar 29, 2020, at 2:14 PM, Robert Armstrong via cctech
> wrote:
>
>> Maciej W. Rozycki wrote:
>> numerous Chemi-Con SXF parts scattered across
>> all boards, some leaking
>
> Yeah, mine is full of "Nippon Chemi-Con" electrolytic too.
>
> What about just gutting the PS chassis and
On Sun, 29 Mar 2020, Robert Armstrong via cctech wrote:
> And then there's a giant PCB, almost 11" square, covered with opamps, 74LS
> logic and discrete parts. There are filter caps, a transformer, and
> switching transistors on this board too so it obviously produces yet another
> power
> Rob Jarratt >robert.jarr...@ntlworld.com> wrote:
> I reverse engineered the schematic of the 12V output board. I
>don't know if that would be of any use? How correct it is I don't know.
Sure, if you don't mind sharing. Everything helps.
Looks like there are five separate PCBs in there.
OK, I posted it here:
https://robs-old-computers.com/2020/03/29/h7874-power-supply/
> -Original Message-
> From: Robert Armstrong
> Sent: 29 March 2020 15:44
> To: r...@jarratt.me.uk; 'General Discussion: On-Topic Posts'
>
> Subject: RE: H7874 power supply
>
> > Rob Jarratt
On Sun, 29 Mar 2020, Rob Jarratt via cctalk wrote:
Thanks Mattis. I do test it with a load, although to be honest I forgot
to do this when I took the measurements yesterday. I use a modern-ish
IDE disk and a load board from a MicroVAX 2000 as the dummy load. I
don’t know if that is sufficient.
> On 29 Mar 2020, at 11:27, Antonio Carlini via cctalk
> wrote:
>
> The following four monitors are available free for pickup in the UK (OX17
> postcode).
>
>
> All appear clean but are untested. All are believed to have been functional
> when stored but that was ~2002/2003-ish.
>
>
>
On Sun, 2020-03-29 at 10:21 -0400, Paul Koning via cctalk wrote:
> > On Mar 28, 2020, at 2:55 PM, dwight via cctalk <
> > cctalk@classiccmp.org> wrote:
> >
> > There are a few reasons most don't like Forth:
> >
> > 1. no type checking ( suppose to save dumb programmers )
> > 2. Often, no
On Sat, Mar 28, 2020 at 06:55:34PM +, dwight via cctalk wrote:
> It is clearly not just a backwards LISP.
LISP is another language that I shied away from in the past, but finally
started exploring a while back.
> It is not Python either.
There's another point in its favor. I've tried to
> On Mar 28, 2020, at 2:55 PM, dwight via cctalk wrote:
>
> There are a few reasons most don't like Forth:
>
> 1. no type checking ( suppose to save dumb programmers )
> 2. Often, no floating point. ( Math has to be well thought out but when
> done right in integer math it has few
The following four monitors are available free for pickup in the UK
(OX17 postcode).
All appear clean but are untested. All are believed to have been
functional when stored but that was ~2002/2003-ish.
Microvitec Cub. Seems to be in its original box.
DEC VRT19-D3.
Vision Master Pro 17.
Rob Jarratt via cctech wrote:
>
>
> > -Original Message-
> > From: cctech On Behalf Of Robert
> > Armstrong via cctech
> > Sent: 29 March 2020 02:29
> > To: cct...@classiccmp.org
> > Subject: H7874 power supply
> >
> > Does anybody have a maintenance print or service manual for the
> -Original Message-
> From: cctech On Behalf Of Robert
> Armstrong via cctech
> Sent: 29 March 2020 02:29
> To: cct...@classiccmp.org
> Subject: H7874 power supply
>
> Does anybody have a maintenance print or service manual for the DEC
> H7874?
> This is the power supply used in
Does anybody have a maintenance print or service manual for the DEC H7874?
This is the power supply used in the BA4xx and R400x cabinets. As you might
guess, I have one that tries to power up but shuts down after a second.
Probably a bad capacitor (or several), but this thing is ridiculously
> -Original Message-
> From: cctalk On Behalf Of Matt Burke via
> cctalk
> Sent: 29 March 2020 10:41
> To: cctalk@classiccmp.org
> Subject: Re: VAXmate PSU
>
> On 29/03/2020 08:50, Mattis Lind via cctalk wrote:
> > Hello Rob,
> >
> > söndag 29 mars 2020 skrev Rob Jarratt :
> >
> >>
Thanks, I do have an isolating transformer as well, so I will use that. I have
done previous tests with a bench PSU on the UC3842 and found it needs 16V to
get going. I just checked the Technical Description and it says the minimum
current on the 5V output is 6.4A and on 12V it is 0.17A. I
On 29/03/2020 08:50, Mattis Lind via cctalk wrote:
> Hello Rob,
>
> söndag 29 mars 2020 skrev Rob Jarratt :
>
>> Thanks Mattis. I do test it with a load, although to be honest I forgot to
>> do this when I took the measurements yesterday. I use a modern-ish IDE disk
>> and a load board from a
Hello Rob,
söndag 29 mars 2020 skrev Rob Jarratt :
> Thanks Mattis. I do test it with a load, although to be honest I forgot to
> do this when I took the measurements yesterday. I use a modern-ish IDE disk
> and a load board from a MicroVAX 2000 as the dummy load. I don’t know if
> that is
Thanks Mattis. I do test it with a load, although to be honest I forgot to do
this when I took the measurements yesterday. I use a modern-ish IDE disk and a
load board from a MicroVAX 2000 as the dummy load. I don’t know if that is
sufficient.
I don’t know enough about PSUs to make the
On 3/28/2020 7:06 PM, dwight via cctalk wrote:
RPN is just there to simplify the interpreter and compiler. It takes some
getting used to. Many claim that infixed is more natural but it is clumsy. One
has to come up with a bunch of rules to make work.
A + B * C
multiply B and C an then add A.
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