24 Sep
2014
24 Sep
'14
12:46 p.m.
Does anyone know offhand what the -15 volt power supply was used for in a BA11-K pdp11/34
enclosure?
Thanks.
24 Sep
24 Sep
1:45 p.m.
On Sep 24, 2014, at 3:46 PM, Roe Peterson <roeapeterson at gmail.com> wrote:
Does anyone know offhand what the -15 volt power
supply was used for in a BA11-K pdp11/34 enclosure?
Thanks.
Some guesses: (a) core memory circuitry, (b) RS-232 drivers. (RS-232 requires + and - 15
volt, give or take. Modern transceiver chips produce those voltages on-chip, but anything
more than 10 or so years old relies on +/- 15V supplies to feed the RS232 driver
circuits.)
paul
1:45 p.m.
I think the H745, -15VDC came in the mos systems, and the H754 +20VDC,
-5VDC came in the core systems.
Paul
On Wed, Sep 24, 2014 at 2:46 PM, Roe Peterson <roeapeterson at gmail.com>
wrote:
Does anyone know offhand what the -15 volt power
supply was used for in a
BA11-K pdp11/34 enclosure?
Thanks.
2:10 p.m.
On Sep 24, 2014, at 4:45 PM, Paul Anderson <useddec at gmail.com> wrote:
I think the H745, -15VDC came in the mos systems, and
the H754 +20VDC,
-5VDC came in the core systems.
Sounds about right. That's what the 11/44 manual specifies for the
MUB slots for MOS and core systems (actually, -15v is only specified
for battery voltage). I would imagine the SPC slots still have -15v
rails, since they're on the B2 pin of every connector in the SPC
section, plus +15v/+8v on CU2.
- Dave
25 Sep
25 Sep
10:10 a.m.
On Sep 24, 2014, at 2:45 PM, Paul Anderson <useddec
at gmail.com> wrote:
I think the H745, -15VDC came in the mos systems, and the H754 +20VDC,
-5VDC came in the core systems.
Right, thanks. This 11/34 has both, actually. Tony had this right too, I forgot MOS
memory needed -15.
Thanks, all.
Paul
On Wed, Sep 24, 2014 at 2:46 PM, Roe Peterson <roeapeterson at gmail.com>
wrote:
> Does anyone know offhand what the -15 volt power supply was used for in a
> BA11-K pdp11/34 enclosure?
>
> Thanks.
>
3741
days inactive
3742
days old
5 comments
5 participants
participants (5)
-
ard＠p850ug1.demon.co.uk -
fraveydank＠gmail.com -
paulkoning＠comcast.net -
roeapeterson＠gmail.com -
useddec＠gmail.com