7 Mar
2015
7 Mar
'15
10:38 p.m.
Hello fellow DEC enthusiasts,
I have a BA11-N mounting box with Q18 9-slot quad-height backplane. The
power supply is toast. My goal is to hack it into something useful.
I'd like to replace the power supply with a sufficiently-powered ATX PSU.
I've read the instructions at:
http://www.diane-neisius.de/pdp11/index_E.html#atx
However, unlike the DEC PSU, the ATX power supply won't supply a 60 Hz line
time clock (LTC) signal to the backplane via BEVENT. So, my question - has
anyone used a standard ATX PSU for a PDP-11 QBUS system, and if so, how'd
you work around the LTC issue?
Once I solve the power issue, I have 11/23 CPU cards, RAM, and SLUs galore.
I'm not planning to make this very power hungry though.
Thanks!
- Earl
7 Mar
7 Mar
10:42 p.m.
Why not just replace the H786?
On Sat, Mar 7, 2015 at 9:38 PM, Earl Evans <earl at retrobits.com> wrote:
Hello fellow DEC enthusiasts,
I have a BA11-N mounting box with Q18 9-slot quad-height backplane. The
power supply is toast. My goal is to hack it into something useful.
I'd like to replace the power supply with a sufficiently-powered ATX PSU.
I've read the instructions at:
http://www.diane-neisius.de/pdp11/index_E.html#atx
However, unlike the DEC PSU, the ATX power supply won't supply a 60 Hz line
time clock (LTC) signal to the backplane via BEVENT. So, my question - has
anyone used a standard ATX PSU for a PDP-11 QBUS system, and if so, how'd
you work around the LTC issue?
Once I solve the power issue, I have 11/23 CPU cards, RAM, and SLUs galore.
I'm not planning to make this very power hungry though.
Thanks!
- Earl
11:17 p.m.
Well, you could make some clock-generation hw and run it off the 5V
standby on ATX. Seems straightforward-enough.
On 03/07/2015 09:38 PM, Earl Evans wrote:
Hello fellow DEC enthusiasts,
I have a BA11-N mounting box with Q18 9-slot quad-height backplane. The
power supply is toast. My goal is to hack it into something useful.
I'd like to replace the power supply with a sufficiently-powered ATX PSU.
I've read the instructions at:
http://www.diane-neisius.de/pdp11/index_E.html#atx
However, unlike the DEC PSU, the ATX power supply won't supply a 60 Hz line
time clock (LTC) signal to the backplane via BEVENT. So, my question - has
anyone used a standard ATX PSU for a PDP-11 QBUS system, and if so, how'd
you work around the LTC issue?
Once I solve the power issue, I have 11/23 CPU cards, RAM, and SLUs galore.
I'm not planning to make this very power hungry though.
Thanks!
- Earl
--
--Joseph Lenox, BS, MS
I'm an engineer. I solve problems.
8 Mar
8 Mar
8:38 a.m.
60 hz? Little wall wart transformer with 1 diode feeding a 7805. Done.
enviado do meu telemovel
Em 08/03/2015 06:57, "Joseph Lenox" <lenox.joseph at gmail.com> escreveu:
Well, you could make some clock-generation hw and run
it off the 5V
standby on ATX. Seems straightforward-enough.
On 03/07/2015 09:38 PM, Earl Evans wrote:
Hello fellow DEC enthusiasts,
I have a BA11-N mounting box with Q18 9-slot quad-height backplane. The
power supply is toast. My goal is to hack it into something useful.
I'd like to replace the power supply with a sufficiently-powered ATX PSU.
I've read the instructions at:
http://www.diane-neisius.de/pdp11/index_E.html#atx
However, unlike the DEC PSU, the ATX power supply won't supply a 60 Hz
line
time clock (LTC) signal to the backplane via BEVENT. So, my question - has
anyone used a standard ATX PSU for a PDP-11 QBUS system, and if so, how'd
you work around the LTC issue?
Once I solve the power issue, I have 11/23 CPU cards, RAM, and SLUs
galore.
I'm not planning to make this very power hungry though.
Thanks!
- Earl
--
--Joseph Lenox, BS, MS
I'm an engineer. I solve problems.
9:19 a.m.
This page discusses making a small pdp-11 system which may be useful:
http://www.pdp-11.nl/ba11-boxes/ba11va/ba11va-info.html
Kirk
On March 8, 2015 at 5:30 AM, "Alexandre Souza" <alexandre.tabajara at
gmail.com> wrote:
60 hz? Little wall wart transformer with 1 diode feeding a 7805.
Done.
enviado do meu telemovel
Em 08/03/2015 06:57, "Joseph Lenox" <lenox.joseph at gmail.com>
escreveu:
Well, you could make some clock-generation hw and
run it off the
5V
standby on ATX. Seems straightforward-enough.
On 03/07/2015 09:38 PM, Earl Evans wrote:
> Hello fellow DEC enthusiasts,
>
> I have a BA11-N mounting box with Q18 9-slot quad-height
backplane. The
> power supply is toast. My goal is to hack it
into something
useful.
>
> I'd like to replace the power supply with a sufficiently-
powered ATX PSU.
> I've read the instructions at:
>
> http://www.diane-neisius.de/pdp11/index_E.html#atx
>
> However, unlike the DEC PSU, the ATX power supply won't supply
a 60 Hz
> line
> time clock (LTC) signal to the backplane via BEVENT. So, my
question - has
> anyone used a standard ATX PSU for a PDP-11
QBUS system, and if
so, how'd
> you work around the LTC issue?
>
> Once I solve the power issue, I have 11/23 CPU cards, RAM, and
SLUs
>> galore.
>> I'm not planning to make this very power hungry though.
>>
>> Thanks!
>>
>> - Earl
>>
>
>
> --
> --Joseph Lenox, BS, MS
> I'm an engineer. I solve problems.
>
> 
3:43 a.m.
On Sat, Mar 07, 2015 at 07:38:58PM -0800, Earl Evans wrote:
However, unlike the DEC PSU, the ATX power supply
won't supply a 60 Hz line
time clock (LTC) signal to the backplane via BEVENT. So, my question - has
anyone used a standard ATX PSU for a PDP-11 QBUS system, and if so, how'd
you work around the LTC issue?
I haven't done it with an ATX PS, but years ago I set up a 4-slot
dual-height box (is that BA-11VA?) that didn't drive BEVENT L, to run
RSX11M+ which of course requires the clock, so I dangled a little piece of
perfboard in the backplane (wire-wrapped to BEVENT L and the power pins)
with a PIC CPU that generated the clock. Code here:
ftp://ftp.dbit.com/pub/pic/kw11l.asm
... and there's an ASCII drawing of the ultra-simple circuit in a comment
block there. If I were doing it now I'd use an 8-pin PIC.
John Wilson
D Bit
9:21 p.m.
On 3/7/2015 11:43 PM, John Wilson wrote:
I haven't done it with an ATX PS, but years ago I
set up a 4-slot
dual-height box (is that BA-11VA?) that didn't drive BEVENT L, to run
RSX11M+ which of course requires the clock, so I dangled a little piece of
perfboard in the backplane (wire-wrapped to BEVENT L and the power pins)
with a PIC CPU that generated the clock. Code here:
ftp://ftp.dbit.com/pub/pic/kw11l.asm
... and there's an ASCII drawing of the ultra-simple circuit in a comment
block there. If I were doing it now I'd use an 8-pin PIC.
John Wilson
D Bit
Can you dig up this include file in the source?
include <p16f84.inc>
I didn't find it in your /pub/pdp11 or at least not a candidate.
I saw the binary is there too, but it would be nice to have all the info
to compile it in one place in case I need it.
thanks
Jim
9 Mar
9 Mar
11:56 a.m.
On Sun, Mar 08, 2015 at 06:21:31PM -0700, jwsmobile wrote:
Can you dig up this include file in the source?
include <p16f84.inc>
I didn't find it in your /pub/pdp11 or at least not a candidate.
I saw the binary is there too, but it would be nice to have all the info to
compile it in one place in case I need it.
p16f84.inc came with the assembler -- I forget whether I was still
using DOS MPASM at that point, or GPASM (the GPLed clone). Anyway the
PIC-CPU-specific defs are all I was pulling out of there, so whatever
the file is on your assembler is right. Maybe that's an 8.3.-ified
version of the filename and pic16f84.inc would be the one to use on
Windows or Linux.
John Wilson
D Bit
8 Mar
8 Mar
12:03 p.m.
On 3/7/2015 10:38 PM, Earl Evans wrote:
Hello fellow DEC enthusiasts,
I have a BA11-N mounting box with Q18 9-slot quad-height backplane. The
power supply is toast. My goal is to hack it into something useful.
I'd like to replace the power supply with a sufficiently-powered ATX PSU.
I've read the instructions at:
http://www.diane-neisius.de/pdp11/index_E.html#atx
However, unlike the DEC PSU, the ATX power supply won't supply a 60 Hz line
time clock (LTC) signal to the backplane via BEVENT. So, my question - has
anyone used a standard ATX PSU for a PDP-11 QBUS system, and if so, how'd
you work around the LTC issue?
Once I solve the power issue, I have 11/23 CPU cards, RAM, and SLUs galore.
I'm not planning to make this very power hungry though.
Thanks!
- Earl
Earl, I did an ATX conversion on my
BA123 to dual 500W ATX PSUs. I used
Brad Parker's QBus POR device for
generating the LTC, but am not sure on
current availability as past emails to
him have gone unanswered.
http://www.heeltoe.com/index.php?n=Pcbs.Qbus-por
A trick is that his LTC output is open
collector, thus needs a pullup unless
your backplane provides.
- J.
9 Mar
9 Mar
9:18 p.m.
I'm also interested in mating an ATX supply with a QBUS backplane. I have a naked
backplane (I think it's either Q18-CD or Q22-CD) that I bought off eBay, and I plan to
(eventually) use it as a dedicated bench test backplane for working on boards. I figured
I'd mate it up with an ATX supply.
--
Mark J. Blair, NF6X <nf6x at nf6x.net>
http://www.nf6x.net/
3372
days inactive
3374
days old
9 comments
9 participants
participants (9)
-
alexandre.tabajara＠gmail.com -
earl＠retrobits.com -
js＠cimmeri.com -
jws＠jwsss.com -
kirkbdavis＠hush.com -
lenox.joseph＠gmail.com -
nf6x＠nf6x.net -
useddec＠gmail.com -
wilson＠dbit.com