11 Jul
2000
11 Jul
'00
2:56 a.m.
At 06:19 PM 7/10/00 -0400, Carlos wrote:
By the way, this weekend
my I/O ROM started to go flaky; on power up, it reports an error 112,
which is a checksum failure. I remember that this happened before and
reseating fixed it, but I haven't had luck this time. I tried other
slots in the ROM drawer too. Guess I need to pry open the ROM capsule
and have a look. This is weird, because both the pin and the through-hole
that make the contacts are gold-plated; they were made to last. I am
afraid that this is a case of bit rot :-( .
Carlos,
Keep me posted about what you find. I've only seen bit rot in the HP
41 plus in ROMs. I've never seen it in other HP machines.
Joe
11 Jul
11 Jul
3:11 a.m.
Ok, here's a preliminary inspection. The ROM tray and the ROM
modules use the pin-and-through hole connection scheme that was
used by HP at the time; this type of interconnection between boards
can be seen in other HP machines such as the HP97 and the HP75.
While the pins are somewhat delicate, this system seems to provide
a good connection, especially since surfaces are gold-plated.
Now enter the HP85 ROM modules. The pc board that they are mounted on
is of the laminated-fiberglass-looking variety. Looking inside
the through-hole, it seems that the miriad layers in the pc board
induce some rugosity in the walls of the through-hole, and these
imperfections can be seen also in the gold plating of the walls.
Indeed, it doesn't seem like the surface of the walls is very
appropriate for plating; I bet that chunks of plating can be scraped off
easily with just a little friction. I think that I need to look inside
the holes with a microscope and a good light; proper illumination
is going to be a problem, though.
If I had a tin through-hole riveter I would try sleeving the holes,
but I don't have one. Anyway, the goal right now is to rule out
bad contacts.
carlos.
Joe wrote:
At 06:19 PM 7/10/00 -0400, Carlos wrote:
--
Carlos Murillo-Sanchez email: cem14(a)cornell.edu
428 Phillips Hall, Electrical Engineering Department
Cornell University, Ithaca, NY 14853
By the way, this weekend
my I/O ROM started to go flaky; on power up, it reports an error 112,
which is a checksum failure. I remember that this happened before and
reseating fixed it, but I haven't had luck this time. I tried other
slots in the ROM drawer too. Guess I need to pry open the ROM capsule
and have a look. This is weird, because both the pin and the through-hole
that make the contacts are gold-plated; they were made to last. I am
afraid that this is a case of bit rot :-( .
Keep me posted about what you find. I've only seen bit rot in the HP
41 plus in ROMs. I've never seen it in other HP machines.
Joe 
6:26 a.m.
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noon
At 07:26 PM 7/11/00 +0100, Tony wrote:
Not many! The problem with them in that the plastic used for the body
of the "zebra-strip" connector flattens out and takes a set after a period
of time. If you look at the ends you'll see that they're oblong and no
longer round. FWIW I meet the guy that invented these things and the guy
that sold them to HP. They still have a few left and I managed to talk them
out of them. I also got the blue print for the things.
Joe
Ok, here's a preliminary inspection. The ROM tray and the ROM
modules use the pin-and-through hole connection scheme that was
used by HP at the time; this type of interconnection between boards
can be seen in other HP machines such as the HP97 and the HP75.
I know them well. Always struck me that they shouldn't work well, but
they do. They seem to have fewer bad contact problems than many other
inter-board connectors (is there an HP41 that's _not_ suffered from bad
contacts at the CPU board-keyboard 'connector'??)
11:15 a.m.
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11:54 a.m.
New subject: PDP 8/I stuff
Hi everyone,
I finally take delivery of my PDP 8/I next week. It comes with a couple of
tape drives and a high speed paper tape reader.
I'm am now looking for anything PDP 8/I related including books, paper tapes,
peripherals (especially an ASR33 teletype), mag tapes (TU58 I think),
engineering
documents and internal cards.
If anyone has any of this stuff they would like to see preserved in a working
system
let me know. I will pay resonable prices for this stuff.
Please though, no pointers to things on ebay. I'm tired of the contrived
frenzy,
bloated prices and constant disassembly of machines to generate more cash
for flipchip or core memory wall art.
Mike
12:29 p.m.
New subject: PDP 8/I stuff
I'm am now looking for anything PDP 8/I related
including books, paper tapes,
peripherals (especially an ASR33 teletype), mag tapes (TU58 I think),
engineering
documents and internal cards.
You don't want TU58 tapes, those are DECtape II's like you'd find on a
PDP-11 or VAX. They're about the size of a cassette tape, but different and
a little thicker.
I believe the right name is TU55/56.
Congrats on the -8/I BTW.
Zane
3:16 p.m.
New subject: PDP 8/I stuff
healyzh(a)aracnet.com wrote:
Thanks. Your are right about the tape drives, they are the reel to reel variety
and it
come with two of them. I can't wait until it gets here and to see the neighbors
faces
as I try to get the thing upstairs at my little townhouse.
If anybody ever has to move stuff like this from the Carolinas I found an
excellent
company that will pickup, crate, shrink wrap and ship for a pretty good price.
Anybody else out there with and 8/i?
Mike
I'm am now
looking for anything PDP 8/I related including books, paper tapes,
peripherals (especially an ASR33 teletype), mag tapes (TU58 I think),
engineering
documents and internal cards.
You don't want TU58 tapes, those are DECtape II's like you'd find on a
PDP-11 or VAX. They're about the size of a cassette tape, but different and
a little thicker.
I believe the right name is TU55/56.
Congrats on the -8/I BTW.
Zane
3:27 p.m.
New subject: PDP 8/I stuff
Anybody else out there with and 8/i?
I had three at one point, but traded one off for an Interdata. Of the two
I have left, one is in need of the silkscreened front panel (just the
panel, not the switches and lights). That's going to be a "fun" and
costly thing to find.
I will likely consolidate the systems at some point, if I can find some
proper racks (the tubular aluminum ones, pre-H960). The machines now are
so hacked up and fooled with its impossible to tell just what goes with
what.
Interestingly, the TU56 controller on one of the systems is made of
System Building Blocks, not Flip-Chips. It looks like it may have been a
production build, not just a hobby or academic hack job. No one seems to
know what that is all about.
William Donzelli
aw288(a)osfn.org
4:38 p.m.
New subject: PDP 8/I stuff
William Donzelli <aw288(a)osfn.org> wrote:
Interestingly, the TU56 controller on one of the
systems is made of
System Building Blocks, not Flip-Chips. It looks like it may have been a
production build, not just a hobby or academic hack job. No one seems to
know what that is all about.
Possibly a TC01 DECtape control, as opposed to the more common
flip-chip-based TC08?
I've never seen one, but I imagine that the TC01 was originally designed
for the PDP-5, so it would have been made with System modules.
The TC01 was designed not for the TU56, or even the TU55, but for the
Type 555 DECtape transports, which used relay control rather than solid
state. So if there are TU56 transports on it, they've probably been
configured for relay control.
12 Jul
12 Jul
4:37 a.m.
New subject: PDP 8/I stuff
I've never seen one, but I imagine that the TC01
was originally designed
for the PDP-5, so it would have been made with System modules.
The TC01 was designed not for the TU56, or even the TU55, but for the
Type 555 DECtape transports, which used relay control rather than solid
state. So if there are TU56 transports on it, they've probably been
configured for relay control.
The transport is actually a TU55. I can't find anything that says TC01. Is
there a MUL (Module Utilization List) floating around on the net I could
compare the machine with?
It does look like the main parts of the controller may be factory done,
but at soon as it gets to interfacing to the transport, things start
looking bad. I would buy that this was upgaded in its lifetime, as you
suggest.
I can shoot some pictures if you like. You will then see what kind of a
mess these machines are!
One thing - there are three rather large sockets, somewhat rectangular,
about 2" by 3", on the backplane. They appear to be unused, but wired in.
They look like the serious type of connectors that IBM and the aerospace
industry sometimes used. Where these originally to interface to a PDP-5?
William Donzelli
aw288(a)osfn.org
11 Jul
11 Jul
5:53 p.m.
New subject: PDP 8/I stuff
William Donzelli wrote:
The machine I am getting is pretty complete I believe. It come mounted in
two 70 inch high racks and is in pretty good condition. I have no idea
exactly
what version of the peripherals I'm getting. It will be like christmas for
me.
I will document the details of my system next week. There may be parts we
could
swap and both end up with more complete systems.
Mike
Anybody else
out there with and 8/i?
I had three at one point, but traded one off for an Interdata. Of the two
I have left, one is in need of the silkscreened front panel (just the
panel, not the switches and lights). That's going to be a "fun" and
costly thing to find.
I will likely consolidate the systems at some point, if I can find some
proper racks (the tubular aluminum ones, pre-H960). The machines now are
so hacked up and fooled with its impossible to tell just what goes with
what.
Interestingly, the TU56 controller on one of the systems is made of
System Building Blocks, not Flip-Chips. It looks like it may have been a
production build, not just a hobby or academic hack job. No one seems to
know what that is all about.
8930
days inactive
8931
days old
11 comments
7 participants
participants (7)
-
ard＠p850ug1.demon.co.uk -
aw288＠osfn.org -
cem14＠cornell.edu -
eric＠brouhaha.com -
healyzh＠aracnet.com -
mcruse＠acm.org -
rigdonj＠intellistar.net