OK, next! As I mentioned, I have two systems I'm working on, and I'm starting
with the 11/23. It uses a Sigma BA11NL-1 chassis - very similar to the DEC
chassis of the similar id.
(Speaking of which... the chassis was in a box with a DEC "11L03-HA" label on
it - I can't work out if whoever owned it upgraded it with the Sigma [which
is Q22] or if DEC supplied the unit with the Sigma. I can't work out why DEC
would have used an outside supplier for that - unless either i) Sigma could
build a chassis much cheaper than DEC could, or ii) DEC was having supply
issues, and turned to Sigma to fill the gap.)
Anyway, so I've had it apart, and it's generally in very good condition...
with this exception in the power supply:
http://ana-3.lcs.mit.edu/~jnc/jpg/PDP11s/SigmaBurnedConnector.jpg
This spade lug appears to be the +5V common, although I'm too lazy to check
the prints to absolutely confirm that (there are two other similar wires
coming out of the transformer, but without the white stripe of this one, and
they both go to a honking great full-wave rectifier, the output of which goes
to a heat sink (!) which appears to be doing double duty as a bus bar).
Clearly, there was probably excessive resistance there somewhere, although
it's not clear if it was across the spade connector itself, or in the
wire-connector junction (note the brown spot on the insulating shield - I
first thought that indicated that the wire-connector joint was the problem,
but iff the spade connector got hot enough, the heat could have gotten into
the wire, and caused that spot).
So here's my question: what do I do? Do I:
- Pull the spade connector off, clean everything well (e.g. with a Dremel
wire brush), and put it back together, and hope?
- Replace the connector on the wire side only (slightly tricky, as there's
not much spare length in the harness, so I can't clip it off, I'd have to cut
the old one off with a Dremel wheel)?
- Try and replace the lug on the board too? (It looks like it got hot enough
to melt the solder - the solder has the surface crazing to it.) That might be
tricky...
- Do nothing and hope (on the basis that it didn't melt down yet :-)?
Whatever I do, of course, I should monitor it, and I'd like to avoid a lot of
grief replacing things unless I really need to, but I'm genuinely uncertain
what the best course is here. Thoughts?
Noel
Have a board here with subject chip on it. Also has 2 IMP-00A's. I assume
what I have is the 8 bit version of the IMP-16. Haven't been able to locate
instruction set for this 8 bit version. All the data sheet says is "CROM's
which implement 8-bit instruction sets are available as standard products."
Seems to be lots of info out there for IMP-16 but anyone heard of this
IMP-8A/521D?
Thanks,
Bill
Well, they do say that the device is there to protect the fuse...
http://www.classiccmp.org/acornia/tmp/fuse.jpg
Found in the chassis of an old 'scope. There's actually originally no
provision for a fuse in the 'scope itself - just a circuit breaker - but
quite why someone would take the trouble to cut a wire and then solder both
ends of the same fuse to it, I have no idea.
cheers
Jules
> From: Chuck Guzis <cclist at sydex.com>
> Do you mean something like the 2.54mm dual-row "Dupont" connector
> shells taking crimp pins?
> e.g. eBay 330875532644
Yes, that's it! How on earth did you find that? I looked on eBay (and then
Googling) for several hours, and couldn't!! :-)
> Paul Anderson <useddec at gmail.com>
> Do you need ones like used on the M7800 (DL11) and KL8?
> I have 20ma cables for these
Thanks; those are indeed the kind/size I'm looking for (quite a few DEC
boards use them), but I think I'm set now (above).
> John Wilson <wilson at dbit.com>
> the housing is technically 44 positions because it goes all the way to
> the edges, but the DEC connectors (like the IDC ribbon-cable
> connectors) skip the outer pairs so you only ever use the middle 40
> pins out of 44.
Interesting... I have a cable with 40-pin connectors (on an old IDE cable;
these are not keyed) and I tried plugging it in, and there is no space at all
on the sides (unlike, say, when one plugs a 10-pin shell into a 14-pin
DLV11-J connector). But looking at the connector carefully, I see that the
side arms of the top retainer piece take up space on the sides - looks like
just enough for a pin. So maybe the '40 pin' Berg headers really are
technically 44 pin size (although they do have only 40 pins).
Speaking of keying... does anyone know the name (let alone a source) for the
little plugs (usually white) that can go into one of the holes on one of those
connector shells, to key it so it can only go in one way round?
Thanks everyone, for all for the help!
Noel
> From: Tothwolf
> So was DEC using both AMP AMPMODU and Berg connectors for the cables?
Yup - and others as well - although seemingly not on the same board type,
though.
Pretty much all the 40-pin connectors I can see here (one a large range of
board types) have Berg on them (although it seems DEC was making the part
themselves under license, because all except one _also_ has a
"|d|i|g|i|t|a|l|" logo on it too); there is one DuPont. The non-DEC Berg and
the DuPont are absolutely identical except for the logo - and are on a pair of
cards which use them for an over-the-back connection, so I suspect they are
the same part, just re-labeled.
The 50's a a mix of Berg and 3M. There are 20's which are Berg. The ones on
the DLV11-J's (the one they gave the AMP part numbers for) aren't marked, nor
are a number of the other small ones.
Noel
> From: Tothwolf
> FCI bought out Dupont's connector division a long time ago, so what you
> are looking for is FCI's Mini-PV series.
> ...
> I'd advise against buying these type of contacts on eBay. 99% of the
> "Berg" or "Dupont" contacts on eBay are knock-offs and don't have
> decent plating (gold flash, if they have any gold on them at all) and
> aren't made to have the correct gripping force. .. they might not even
> fit a real HT-95.
Hi, thanks for all that great info. The 'gold flash' issue was new to me;
for those who are likewise unfamiliar with it, I found this nice write-up:
http://www.dfrsolutions.com/uploads/white-papers/Gold_Flash.pdf
Alas, I've already ordered some of the 'eBay knockoff' pins; when they get
here, I will look them over, and if poor quality, take appropriate action...
> From: John Wilson
> Digikey 3M9123-ND (3M 3435-0 "conn socket keying plug") is the version
> that fits into an IDC connector.
By pure chance, I later discovered, as I was reading the writeup on the
DLV11-J, that they gave AMP part numbers for the shell (10-pin, I assume),
contacts, and plug (they call it a "key pin"), and they seem to still work.
Here they are, if anyone has any use for them:
87133-5 Connector shell
87124-1 Contact
87179-1 Keying pin
How odd to find them in the DEC Interfaces Handbook!
Noel
Hi
I've found an old binary for the original TETRIS called TETRIS.SAV. I
believe it is a runnable binary made for RT-11 orginally run on of the
russian PDP-11 clones.
Now, I would like to run this under RTEM-11 on RSX-11M+, since that is
what I have available.
But I find very little documentation and I have no real idea how RTEM-11
works. Does anyone here with any experience want to give me some
pointers?
Simply, what do I do with an RTEM-11 installation and TETRIS.SAV?
Assume no or little knowledge on my side :)
/P
Hey, all, I'm looking for a source for 40-pin connector shells (to hold female
pins) for 2.54mm so-called Berg or Du Pont connectors. Anyone have a source
they can point me at? (I would call these male shells - since they go into the
female shells with male pins typically found on circuit boards - but I gather
the terminology is somewhat confused.)
The small ones (1-10 pins) are easy to find (they are used for audio/USB
connectors); the 40-pin females for use on ribbon cables are also easy to
find, as are the males that go into PCBs... but the 40-pin insertable pin
females appear to be unobtanium.
(I want them because a number of old DEC interface cards use them for cables,
and I refuse to pay $139 or whatever for a cable that's made of a total of a
couple of bucks worth of parts - I'm quite happy to roll my own.)
BTW, to quickly introduce myself (since this is my first message to the list);
I did a lot of work with PDP-11s 'back in the day', both as a software
development environment (using PWB Unix - roughly V6 - and later Ultrix), as
an application platform (multi-protocol routers, using LSI-11s), and also some
prototyping of high-speed network interfaces (1 and 10 Mbit/second rings).
I now have a couple of 11s (a 23 and an 84) which I'm trying to get running.
You'll be hearing lots more from me Real Soon Now as I get into that
project... :-)
Noel
