> -----Original Message-----
> From: cctalk-bounces at classiccmp.org [mailto:cctalk-bounces at classiccmp.org]
> On Behalf Of Shoppa, Tim
> Sent: 06 January 2011 19:53
> To: cctalk at classiccmp.org
> Subject:
>
> > A while back I mentioned that I have a MicroVAX 3400 with one of the
> > H7868 PSUs not wanting to work (green light fails to come on). I have
> > just tried the "faulty" PSU in a MicroVAX 3500 and it works just fine.
> > I took a PSU from the 3500 and put it in the 3400 and it does not work
> > in the 3400 either, only in the 3500. So clearly there is something
> > else that is causing the problem and I am looking for suggestions,
> > especially as the machine is in an awkward location and hard to
> > dismantle speculatively. As a reminder this machine was working fine
> > and I had not done anything at all to it prior to its failure, I had
> > not moved it, changed any components or anything
>
> Without sufficient DC load the H7868 will fail to start up.
>
> One supply goes to half the slots. There's a Q-bus card That is nothing
but a
> bunch of power resistors for this situation, although I Usually preferred
to put in
> a KDA50 set 'cuz I had a bunch of those :-).
>
> Tim.
(adding subject line back)
In this case I think the load should be there because it is the right hand
PSU that won't start, this powers the 6 slots on the right and these contain
the memory and CPU, so there should be enough load for the PSU to work.
There is indeed a resistor card in the leftmost slot, but the left hand PSU
lights up fine.
Regards
Rob
> A while back I mentioned that I have a MicroVAX 3400 with one of the H7868
> PSUs not wanting to work (green light fails to come on). I have just tried
> the "faulty" PSU in a MicroVAX 3500 and it works just fine. I took a PSU
> from the 3500 and put it in the 3400 and it does not work in the 3400
> either, only in the 3500. So clearly there is something else that is causing
> the problem and I am looking for suggestions, especially as the machine is
> in an awkward location and hard to dismantle speculatively. As a reminder
> this machine was working fine and I had not done anything at all to it prior
> to its failure, I had not moved it, changed any components or anything
Without sufficient DC load the H7868 will fail to start up.
One supply goes to half the slots. There's a Q-bus card
That is nothing but a bunch of power resistors for this situation, although I
Usually preferred to put in a KDA50 set 'cuz I had a bunch of those :-).
Tim.
Nick writes:
> Or even some blank prototype style boards would be helpful.
44-pin edge prototype boards are still readily available:
http://www.vectorelect.com/Product/Plugbord/PB44C.htm
Many in stock at Digikey, Mouser, etc. Probably hanging with
The other vector stuff at any surviving local electronics shop(s)
Near you.
Zane writes:
> I'm getting ready to test out my 9-Track tape drive before hauling it
> into work for some data recovery. I have a box of brand new tapes,
> which unfortunately haven't been stored under ideal conditions for
> most of their life (they're probably about 20 years old). Currently
> they're in the garage, which at the moment is close to freezing. How
> should I go about bringing the tapes to room temp?
If they've been stored under poor conditions for 20 years, I'm not
sure exactly how they're treated in the next few days is gonna matter.
If they had data on them and had seen temperature swings, you might
want to retension them before using. But if they're blank and gonna
be used for testing the transport anyway, hard to see how this can matter.
I would be hesitant to retension a tape with valuable data on a drive
that had the head in contact with the tape. (Stiction). Retensioning
is far from a cure-all.
Why does the concept of retensioning exist at all? If a tape
is stored under adverse temperature or humidity conditions, the
different rate of thermal expansion of the reel and tape, or
between the inner tape and outer tape, can cause "bumps" to
form in the winding and require an uneven rate of rotation
of the hub to spool off the tape at 25 IPS or 75 IPS or
whatever the drive runs at.
Tim.
I've been asked to re-instate the download for the DSD-80 full screen
debugger that I had up here: http://www.retroarchive.org/cpm/lang/lang.htm
Since TCJ is essentially dead and buried, does anyone know who I can
contact in order to get some kind of permission to put that back up for
download?
Thanks!
g.
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Political correctness is a doctrine, fostered by a delusional, illogical
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holds forth the proposition that it is entirely possible to pick up a turd
by the clean end.
Hi all.
In order to make room for an 11/44 I'm giving away a PDP-11/23 with two
RL01 drives. I have a bunch of spare Q-BUS cards for the 11/23 and I
wonder if any of them are compatible with the 11/73.
You see, I just got an 11/73 which is quite empty (a CPU and some
memory) and I don't want to give away something that's useful in the 11/73.
So, here is what I got for the 11/23:
Memory: M7506, M8043, M8044, M8047, M8059, M8067
Peripherals:
M7513 RQDXE RQDX extender for RQDX2/3
M7941 DRV11 16-bit parallel line unit
M7954 IBV11 IEC general purpose
M7957 DZV11-M 4-line double-buffered async EAI MUX
M8013 RLV11 RL01/RL02 disk control 18-bit
M8014 RLV11
M8027 LPV11 Printer interface module
M8061 RLV12 RL01/RL02 disk control
Other:
M9401 Bus extender?
M9400-YB Terminator (11/03)
M7942 MRV11-AA Space for 4K 16-bit PROM
M7952 KWV11 Programmable realtime clock
If I've understood the matter correctly the 11/73 can utilize 22 bits of
the Q-BUS but the 11/23 only 18 bits and that means that some cards are
18 bit only and others 22 bit only.
I think I will hang on to the RLV12 and RQDXE, anything else? It would
be great if the memory was compatible.
Thanks in advance,
Pontus.
I'm getting ready to test out my 9-Track tape drive before hauling it
into work for some data recovery. I have a box of brand new tapes,
which unfortunately haven't been stored under ideal conditions for
most of their life (they're probably about 20 years old). Currently
they're in the garage, which at the moment is close to freezing. How
should I go about bringing the tapes to room temp?
The main 4 tapes to be read have been stored under proper conditions
for most of their life.
Zane
--
| Zane H. Healy | UNIX Systems Administrator |
| healyzh at aracnet.com | OpenVMS Enthusiast |
| | Photographer |
+----------------------------------+----------------------------+
| My flickr Photostream |
| http://www.flickr.com/photos/33848088 at N03/ |
Happy new decade to all members of this list and their families.
[Yes, I do start counting from 0 normally. But the calendar doesn't :-(,
and thus I think that new centrieies, decades, etc start with years
ending in '1'.]
-tony
Hey everyone, does anyone have any of the 44-pin expansion cards for the
Cosmac Elf? I am looking for a video board, disk controller, or
keyboard interface specifically. Or even some blank prototype style
boards would be helpful.
Thanks!
Nick
