DEC BA350s, BA356s, drives, tapes, etc

[Paul Anderson via cctalk]

I have numerous BA350 and BA356 enclosures available along with the power
supplies, etc.

I will sell separately, or try to configure to your request. Please contact
me off list.

Shipping from 61820, Champaign, IL area

Thanks, Paul

Re: BBS software was Re: looking at buying a pocket PC / PDA

[geneb via cctalk]

On Wed, 1 Nov 2017, Warner Losh via cctalk wrote:


On Wed, Nov 1, 2017 at 12:29 PM, Ethan via cctalk 
wrote:


I'd get a RS232toWIFI dongle, they're cheap and easy to make a connection

via simple terminal software to an outside telnet target.



I don't think the RS232 to WIFI dongles from the one guy are often
unavailable. I think the creator hand solders them in small batches or
something.



The ESP 8266's are available a dime a dozen and often have the proper
firmware burned into them. At worst, you have to put a RS-232 DB-xx
connector on and maybe a level shifter (depending on the ESP board you
have, though most don't have them)...

...and a pair of MAX232's if you plan on connecting it to real hardware 
equipped with an RS-232 port.


I'd suggest starting with a NodeMCU. :)

g.

--
Proud owner of F-15C 80-0007
http://www.f15sim.com - The only one of its kind.
http://www.diy-cockpits.org/coll - Go Collimated or Go Home.
Some people collect things for a hobby.  Geeks collect hobbies.

ScarletDME - The red hot Data Management Environment
A Multi-Value database for the masses, not the classes.
http://scarlet.deltasoft.com - Get it _today_!

Re: BBS software was Re: looking at buying a pocket PC / PDA

[geneb via cctalk]

On Wed, 1 Nov 2017, Ethan via cctalk wrote:


I'd get a RS232toWIFI dongle, they're cheap and easy to make a connection
via simple terminal software to an outside telnet target.


I don't think the RS232 to WIFI dongles from the one guy are often 
unavailable. I think the creator hand solders them in small batches or 
something.



It's a great unit for doing "dial-out" only.  Forget incoming though.

g.

--
Proud owner of F-15C 80-0007
http://www.f15sim.com - The only one of its kind.
http://www.diy-cockpits.org/coll - Go Collimated or Go Home.
Some people collect things for a hobby.  Geeks collect hobbies.

ScarletDME - The red hot Data Management Environment
A Multi-Value database for the masses, not the classes.
http://scarlet.deltasoft.com - Get it _today_!

An interesting read

[dwight via cctalk]

Look at Dr Dobb's August 1979. There is an article on computer crime. It is 
interesting how times have changed.

Dwight

Re: BBS software was Re: looking at buying a pocket PC / PDA

[Warner Losh via cctalk]

On Wed, Nov 1, 2017 at 12:29 PM, Ethan via cctalk 
wrote:

> I'd get a RS232toWIFI dongle, they're cheap and easy to make a connection
>> via simple terminal software to an outside telnet target.
>>
>
> I don't think the RS232 to WIFI dongles from the one guy are often
> unavailable. I think the creator hand solders them in small batches or
> something.
>

The ESP 8266's are available a dime a dozen and often have the proper
firmware burned into them. At worst, you have to put a RS-232 DB-xx
connector on and maybe a level shifter (depending on the ESP board you
have, though most don't have them)...

Warner

Re: BBS software was Re: looking at buying a pocket PC / PDA

[Ethan via cctalk]

I'd get a RS232toWIFI dongle, they're cheap and easy to make a connection
via simple terminal software to an outside telnet target.


I don't think the RS232 to WIFI dongles from the one guy are often 
unavailable. I think the creator hand solders them in small batches or 
something.


- EThan


--
: Ethan O'Toole

Re: DEC RX03 RT11A file extractor

[John Wilson via cctalk]

On Wed, Nov 01, 2017 at 10:10:00AM -0700, Chuck Guzis via cctalk wrote:
>A bit more on the RX03 floppies and why putr probably dies.
>
>The home block for these contains the usual "DECRT11A" and "RT11A" tags,
>as well as the Rad-50 "V3A", cluster size and first directory segment
>pointer, but everything else in the block is set to ASCII space (hex
>20), including the checksum.
>
>Is this usual for these floppies?

No, but it's what (at least some versions of) RSTS's "FIT" utility does
when initializing a directory.  If you'd be willing to send me a .DSK file,
I'd be happy to have a little talk with PUTR.  It's lng overdue for an
upgrade (and I'm lng overdue for finishing a portable version I started
ages ago, as a set of FUSE drivers I was going to roll into a utility that
didn't rely on Linux's FUSE and would run anywhere).

John Wilson
D Bit

Re: DEC RX03 RT11A file extractor

[Chuck Guzis via cctalk]

A bit more on the RX03 floppies and why putr probably dies.

The home block for these contains the usual "DECRT11A" and "RT11A" tags,
as well as the Rad-50 "V3A", cluster size and first directory segment
pointer, but everything else in the block is set to ASCII space (hex
20), including the checksum.

Is this usual for these floppies?

--Chuck

Re: H7861 PSU issues

[Aaron Jackson via cctalk]

That's good to know. I'll head over to Maplin after work and pick up
some timers and sockets.

I removed one of the suspicious ceramic caps and tested it and it came
out fine. The other cap is shared with the other oscillator so I assume
it is fine. 

Thanks!

Aaron.

Rob Jarratt via cctech  wrote:

> I had a dead 555 on a completely different PSU, so it could be worth
> checking. I socketed it when I replaced it so it was easy to replace again.
> 
> Also, just because a capacitor doesn't appear swollen or show signs of
> leakage, it seems that this doesn't necessarily mean that it doesn't need
> replacing. In yet another PSU that I repaired recently, replacing the
> capacitors fixed it, although in the end I think the one that really fixed
> it was showing signs of leakage. On a lot of caps that I replace they show
> no leakage signs, but I do see a bit of a deposit on the negative terminal,
> I am not sure if this is a sign of any kind of problem.
> 
> Regards
> 
> Rob
> 
> > -Original Message-
> > From: cctech [mailto:cctech-boun...@classiccmp.org] On Behalf Of Aaron
> > Jackson via cctech
> > Sent: 31 October 2017 21:26
> > To: cct...@classiccmp.org
> > Subject: Re: H7861 PSU issues
> > 
> > Just had another look after watching a video about how switch mode power
> > supplies work On the small control board connecting to J4, there are
> two
> > D44Q1 transistors. As expected, there is about 65KHz going into the base
> of the
> > transistor for the 5V side. However, there is no signal going into the
> base of the
> > transistor for the 12V side, from pin 3 of the 555. So, it looks like the
> problem is
> > coming from around here. I measured the suspicious components around the
> > 555 and they seem fine.
> > 
> > How likely is it that the 555 is dead? There is 10v going into pin 8,
> which I
> > believe is correct.
> > 
> > Thanks,
> > 
> > Aaron.
> > 
> > 
> > 
> > 
> > 
> > Aaron Jackson writes:
> > 
> > > Hi everyone,
> > >
> > > I've been trying to figure out what is wrong with the 12V rail on my
> > > H7861 (BA11-S) power supply. It's showing about 4.2V. The 5V rail is
> > > spot on.
> > >
> > > Page 39 of the following schematics is the main part board of the PSU.
> > > http://bitsavers.org/pdf/dec/qbus/MP01233_BA11-S_schem_Mar81.pdf
> > >
> > > Going into the collector of Q3 is about 80V coming straight from T2 (I
> > > think I measured it at about 100Hz), but the emitter is putting out
> > > the 4.2V, which is the same as the base voltage and output voltage. I
> > > tried replacing this transistor because the hFE was about 80 and a
> > > good one was about 120. Unfortunately it didn't do anything.
> > >
> > > None of the capacitors look swollen and I don't see any leakage. There
> > > is a smaller board which I think goes into J4. The 12V side seems to
> > > have a 555 timer and adjusting the pot doesn't change the voltage at
> > > all.
> > >
> > > My understanding of switchmode power supplies is very poor. Does
> > > anyone have some pointers on what to check or what might be the possible
> > cause?
> > >
> > > Hopefully I can get my PDP up and running again... Only got about 20
> > > minutes use out of it.
> > >
> > > Thanks!
> > >
> > > Aaron.
> > 
> > 
> > --
> > Aaron Jackson
> > PhD Student, Computer Vision Laboratory, Uni of Nottingham
> > http://aaronsplace.co.uk

Re: DECwriter II available for pickup in Gosport, Hants, UK

[Paul Drescher via cctalk]

Re: Which Dec Emulation is the MOST useful and Versatile?

[Paul Koning via cctalk]

> On Oct 31, 2017, at 5:59 PM, allison via cctalk  wrote:
> 
> ...FYI rope core was basically many
> transformers either with a wire
> in for the bit or wire around for the not bit.  The cores for rope
> didn't change magnetic state like
> coincident current cores of the bistable type as that allowed read write
> but was DRO (destructive
> read out with re-write) which is the more familiar core and why it had a
> shorter read time and a
> longer cycle time between reads.

Actually, that's not accurate.  Core rope memory (Apollo Computer style) does 
use memory cores.  You can find it described well on a web page by Brent 
Halpern that discusses that and other (transformer style) memories.  In core 
rope memory, the selected core has its state changed by the combined select 
currents, and then it delivers pulses to whichever sense lines are threaded 
through that core when the core is reset again.

The Electrologica X1 has a core ROM that also uses memory cores, but in a 
different way than core rope.

paul

RE: DECwriter II available for pickup in Gosport, Hants, UK

[Rob Jarratt via cctalk]

I just wish I could give this a home :-( :-(

> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Adrian
> Graham via cctalk
> Sent: 01 November 2017 10:45
> To: General Discussion: On-Topic and Off-Topic Posts 
> Subject: DECwriter II available for pickup in Gosport, Hants, UK
> 
> Hi folks,
> 
> As the subject says. It's been stored in a garage for many years but is in 
> pretty
> good condition. Free for pickup.
> 
> Cheers,
> 
> --
> adrian/witchy
> Owner of Binary Dinosaurs, the UK's biggest home computer collection?
> www.binarydinosaurs.co.uk

DECwriter II available for pickup in Gosport, Hants, UK

[Adrian Graham via cctalk]

Hi folks,

As the subject says. It's been stored in a garage for many years but is in
pretty good condition. Free for pickup.

Cheers,

-- 
adrian/witchy
Owner of Binary Dinosaurs, the UK's biggest home computer collection?
www.binarydinosaurs.co.uk

RE: H7861 PSU issues

[Rob Jarratt via cctalk]

I had a dead 555 on a completely different PSU, so it could be worth
checking. I socketed it when I replaced it so it was easy to replace again.

Also, just because a capacitor doesn't appear swollen or show signs of
leakage, it seems that this doesn't necessarily mean that it doesn't need
replacing. In yet another PSU that I repaired recently, replacing the
capacitors fixed it, although in the end I think the one that really fixed
it was showing signs of leakage. On a lot of caps that I replace they show
no leakage signs, but I do see a bit of a deposit on the negative terminal,
I am not sure if this is a sign of any kind of problem.

Regards

Rob

> -Original Message-
> From: cctech [mailto:cctech-boun...@classiccmp.org] On Behalf Of Aaron
> Jackson via cctech
> Sent: 31 October 2017 21:26
> To: cct...@classiccmp.org
> Subject: Re: H7861 PSU issues
> 
> Just had another look after watching a video about how switch mode power
> supplies work On the small control board connecting to J4, there are
two
> D44Q1 transistors. As expected, there is about 65KHz going into the base
of the
> transistor for the 5V side. However, there is no signal going into the
base of the
> transistor for the 12V side, from pin 3 of the 555. So, it looks like the
problem is
> coming from around here. I measured the suspicious components around the
> 555 and they seem fine.
> 
> How likely is it that the 555 is dead? There is 10v going into pin 8,
which I
> believe is correct.
> 
> Thanks,
> 
> Aaron.
> 
> 
> 
> 
> 
> Aaron Jackson writes:
> 
> > Hi everyone,
> >
> > I've been trying to figure out what is wrong with the 12V rail on my
> > H7861 (BA11-S) power supply. It's showing about 4.2V. The 5V rail is
> > spot on.
> >
> > Page 39 of the following schematics is the main part board of the PSU.
> > http://bitsavers.org/pdf/dec/qbus/MP01233_BA11-S_schem_Mar81.pdf
> >
> > Going into the collector of Q3 is about 80V coming straight from T2 (I
> > think I measured it at about 100Hz), but the emitter is putting out
> > the 4.2V, which is the same as the base voltage and output voltage. I
> > tried replacing this transistor because the hFE was about 80 and a
> > good one was about 120. Unfortunately it didn't do anything.
> >
> > None of the capacitors look swollen and I don't see any leakage. There
> > is a smaller board which I think goes into J4. The 12V side seems to
> > have a 555 timer and adjusting the pot doesn't change the voltage at
> > all.
> >
> > My understanding of switchmode power supplies is very poor. Does
> > anyone have some pointers on what to check or what might be the possible
> cause?
> >
> > Hopefully I can get my PDP up and running again... Only got about 20
> > minutes use out of it.
> >
> > Thanks!
> >
> > Aaron.
> 
> 
> --
> Aaron Jackson
> PhD Student, Computer Vision Laboratory, Uni of Nottingham
> http://aaronsplace.co.uk