25 Nov
2007
25 Nov
'07
2:29 a.m.
Esteemed listmembers;
I am restoring a ca. 1985 IBM 5271---the so-called 3270 PC. I
received it intact, with a full complement of cards, cables, etc. It
looks very much like it was shut down, removed from its original
office installation, and then apparently left somewhere the squirrels
could get to it (thus, "restoring"). I've vacuumed about forty pounds
of sunflower seed hulls out of it. Blessedly, I haven't found any
other signs of animal inhabitation.
Anyway, my irrational fear of contracting hantavirus aside, I am
wondering if somebody could tell me about what I suspect is the host
interface adapter. All card slots are occupied:
1 - Async Adapter
2 - 5271 Graphics Adapter APA option
3 - 5271 Graphics Adapter
4 - 64-256KB Memory expansion card
5 - 5160 ST412 controller
6 - 5160 floppy controller
7 - the card I need help identifying
8 - 5271 Keyboard Adapter
As there is no 3270 coax card and no open slot to have once held one,
I suspect that the 3270 host interface is the unknown card in slot 7.
I own IBM SDLC and Bisync adapter cards, and this one doesn't look
like either.
Physical characteristics:
* 8-bit, short card.
* One DB25F on the bulkhead.
* 9x Oki M37S64-20; apparently 64Kx1 memories.
* 34 pin .100" header, vertically, at back end of card (J2)
* one 4-pos DIP switch at top right.
* Pretty much everything else on the card is 74LS-series TTL or passive.
It's built like IBM made it, but I can't find any obvious IBM-style
part number on it, unless it's 2683541. Google is silent on this
number. (update: I just noticed 6320999 in the etch, but that hasn't
gotten me any closer to an answer).
Anybody have any guesses? What other host attachment options were
available for the 5271, besides 3270 coax?
Thanks!
ok
bear
25 Nov
25 Nov
11:04 a.m.
r.stricklin wrote:
Esteemed listmembers;
I am restoring a ca. 1985 IBM 5271---the so-called 3270 PC. I received
it intact, with a full complement of cards, cables, etc. It looks very
much like it was shut down, removed from its original office
installation, and then apparently left somewhere the squirrels could get
to it (thus, "restoring"). I've vacuumed about forty pounds of sunflower
seed hulls out of it. Blessedly, I haven't found any other signs of
animal inhabitation.
Anyway, my irrational fear of contracting hantavirus aside, I am
wondering if somebody could tell me about what I suspect is the host
interface adapter. All card slots are occupied:
1 - Async Adapter
2 - 5271 Graphics Adapter APA option
3 - 5271 Graphics Adapter
4 - 64-256KB Memory expansion card
5 - 5160 ST412 controller
6 - 5160 floppy controller
7 - the card I need help identifying
8 - 5271 Keyboard Adapter
As there is no 3270 coax card and no open slot to have once held one, I
suspect that the 3270 host interface is the unknown card in slot 7. I
own IBM SDLC and Bisync adapter cards, and this one doesn't look like
either.
Physical characteristics:
* 8-bit, short card.
* One DB25F on the bulkhead.
* 9x Oki M37S64-20; apparently 64Kx1 memories.
* 34 pin .100" header, vertically, at back end of card (J2)
* one 4-pos DIP switch at top right.
* Pretty much everything else on the card is 74LS-series TTL or passive.
It's built like IBM made it, but I can't find any obvious IBM-style part
number on it, unless it's 2683541. Google is silent on this number.
(update: I just noticed 6320999 in the etch, but that hasn't gotten me
any closer to an answer).
Anybody have any guesses? What other host attachment options were
available for the 5271, besides 3270 coax?
Thanks!
ok
bear
I'm digging in my secret archives. I have just one clue so far -
somebody called it a 'printer/memory' card. Based on your description
of it and this clue, I doubt that it is the comm card for the machine.
Mike
5:23 p.m.
On Nov 25, 2007, at 8:04 AM, Michael B. Brutman wrote:
I'm digging in my secret archives. I have just
one clue so far -
somebody called it a 'printer/memory' card. Based on your
description of it and this clue, I doubt that it is the comm card
for the machine.
This is the same card as mine, right here. I'm not sure I buy the
seller's description of it as a parallel printer card, though it's
certainly possible. I could accept the description if somebody were
to find some other corroborating evidence.
http://cgi.ebay.com/IBM-PC-XT-Parallel-Port-Card-ISA-Parallel-Printer-
Card_W0QQitemZ190173053919QQihZ009QQcategoryZ74946QQssPageNameZWDVWQQrdZ
1QQcmdZViewItem
Interestingly, it was also removed from a 5271.
Actually, the more I think about it, the more it makes sense that
it's a parallel card. Would the 5271 have been capable of using the
Async Adapter as a host interface? That's the only remaining I/O card
in the machine.
ok
bear
5:34 p.m.
I have the exact same card, from my 5271. I have no idea if it's
actually a parallel port card or not, though I suppose I could test it
out :).
However, my 5271 originally (a long time ago, before I inherited it) had
a card with a BNC connector on the back, which sounds like it may have
been a host interface. Unfortunately I didn't get the card when I
inherited the machine (the previous user removed it to install a modem
in its place), so I can't provide more info. There's a chance I may be
able to get in touch with him over the holidays, and if so I'll see if
he still has it lying around somewhere...
Josh
r.stricklin wrote:
On Nov 25, 2007, at 8:04 AM, Michael B. Brutman wrote:
I'm digging in my secret archives. I have
just one clue so far -
somebody called it a 'printer/memory' card. Based on your
description of it and this clue, I doubt that it is the comm card for
the machine.
This is the same card as mine, right here. I'm not sure I buy the
seller's description of it as a parallel printer card, though it's
certainly possible. I could accept the description if somebody were to
find some other corroborating evidence.
http://cgi.ebay.com/IBM-PC-XT-Parallel-Port-Card-ISA-Parallel-Printer-Card_…
Interestingly, it was also removed from a 5271.
Actually, the more I think about it, the more it makes sense that it's
a parallel card. Would the 5271 have been capable of using the Async
Adapter as a host interface? That's the only remaining I/O card in the
machine.
ok
bear
6:07 p.m.
Just did some testing, threw the card into my IBM PC and it shows up as
a parallel port card under Snooper. So I'd guess that's what it is :).
Josh
Josh Dersch wrote:
I have the exact same card, from my 5271. I have no
idea if it's
actually a parallel port card or not, though I suppose I could test it
out :).
However, my 5271 originally (a long time ago, before I inherited it)
had a card with a BNC connector on the back, which sounds like it may
have been a host interface. Unfortunately I didn't get the card when
I inherited the machine (the previous user removed it to install a
modem in its place), so I can't provide more info. There's a chance I
may be able to get in touch with him over the holidays, and if so I'll
see if he still has it lying around somewhere...
Josh
r.stricklin wrote:
On Nov 25, 2007, at 8:04 AM, Michael B. Brutman wrote:
I'm digging in my secret archives. I have
just one clue so far -
somebody called it a 'printer/memory' card. Based on your
description of it and this clue, I doubt that it is the comm card
for the machine.
This is the same card as mine, right here. I'm not sure I buy the
seller's description of it as a parallel printer card, though it's
certainly possible. I could accept the description if somebody were
to find some other corroborating evidence.
http://cgi.ebay.com/IBM-PC-XT-Parallel-Port-Card-ISA-Parallel-Printer-Card_…
Interestingly, it was also removed from a 5271.
Actually, the more I think about it, the more it makes sense that
it's a parallel card. Would the 5271 have been capable of using the
Async Adapter as a host interface? That's the only remaining I/O card
in the machine.
ok
bear
26 Nov
26 Nov
5:54 p.m.
However, my 5271 originally (a long time ago, before I inherited it) had
a card with a BNC connector on the back, which sounds like it may have
been a host interface. Unfortunately I didn't get the card when I
inherited the machine (the previous user removed it to install a modem
in its place), so I can't provide more info. There's a chance I may be
able to get in touch with him over the holidays, and if so I'll see if
he still has it lying around somewhere...
I have something here that might be related, althoguh I don't think it
was made by IBM.
It's a full-length 8-bit card with a single BNC connector on the bracket.
The outer of the BNC is isolated fro mthe bracket. The silkscreen on the
board gives the name 'PC/3278'
There's a 2*30 set of edge fingers at the top front of the PCB pointign
upwards. THe board is of such a shape that a socket could be fitted here
and the cover would still go on the PC.
The main components on the board are :
8X305 microcontorller
3 24 pin EPROMs (I can't see the type without peeling off the labels)
8K of SRAM (4 off 6116)
DP8340 and DP8341 (I have seen these chips befroe in 3270-related devices)
Lots of TTL
8MHz and 18.868MHz crystaks
-tony
9:33 p.m.
Josh Dersch wrote:
However, my 5271 originally (a long time ago, before I
inherited it)
had a card with a BNC connector on the back, which sounds like it may
have been a host interface.
A long time ago we used some PC/3270s and when they
were junked I saved
a few of the cards with BNC connectors so that I could salvage the BNC
connector. I have one left. It is 8-bit and almost square. There is some
standard TTL, one Toshiba package (gate array ?), one IBM SLT package,
and a pulse transformer. It has a DIP switch with a single switch to
select slot 8 or slots 1-7.
What was special about slot 8?
-chuck
27 Nov
27 Nov
5:22 p.m.
Josh Dersch wrote:
In a true-blue IBM PC/XT (5160) or PortablePC (5155), and AFAIK very few, if
any clones, the data bus on slot 8 is wired to the opposite side of a bus
buffer to the data bus to the other 7 sltos. For that reason, the card in
slot 8 has to assert (pull low) one pin on the conenctor on read cycles
to that board (I forget the exact pin, I can look it up if you need it).
The IBM Async card (RS232 card) was one card that could do this (jumper
selected). I have heard that one reason such a card was included with
every PC/XT was that it was bout the only thing that could go in slot 8,
and by putting it there at the factory it avoided too many calls from
customers 'Why doesn't the XYZ card work properly in my new XT?'
I believe some Microsoft Bus Mouse cards had this facility too. I know I
modified a 24 line parallel card (8255 based, the Maplin kit if anyone
remembers that) to work there (I didn't get a real IBM Async card in my
first XT, I bought a clone 2-port one that wnet in one of the other
slots, but I wasn't goign to waste slot 8...)
One particularly clueless piece of mechanical design is that the chassis
of a 5155 PortablePC is about 1/4" to short to fit the Async card in
slot 8. Thus slot 8 is essentially a wasted slot in that machine.
-tony
However, my 5271 originally (a long time ago,
before I inherited it)
had a card with a BNC connector on the back, which sounds like it may
have been a host interface.
A long time ago we used some PC/3270s and when they
were junked I saved
a few of the cards with BNC connectors so that I could salvage the BNC
connector. I have one left. It is 8-bit and almost square. There is some
standard TTL, one Toshiba package (gate array ?), one IBM SLT package,
and a pulse transformer. It has a DIP switch with a single switch to
select slot 8 or slots 1-7.
What was special about slot 8? 
28 Nov
28 Nov
5:18 p.m.
On Tuesday 27 November 2007 17:22, Tony Duell wrote:
Hm. Remembering an XT-type MB I had (maybe still have?) that someone had put
black electrical tape over the top of one of the slot connectors, and if
that was maybe slot 8, and wondering if I still have that board, maybe...
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
What was
special about slot 8?
In a true-blue IBM PC/XT (5160) or PortablePC (5155), and AFAIK very few,
if any clones, the data bus on slot 8 is wired to the opposite side of a
bus buffer to the data bus to the other 7 sltos. For that reason, the card
in slot 8 has to assert (pull low) one pin on the conenctor on read cycles
to that board (I forget the exact pin, I can look it up if you need it).
The IBM Async card (RS232 card) was one card that could do this (jumper
selected). I have heard that one reason such a card was included with
every PC/XT was that it was bout the only thing that could go in slot 8,
and by putting it there at the factory it avoided too many calls from
customers 'Why doesn't the XYZ card work properly in my new XT?'
25 Nov
25 Nov
6:11 p.m.
r.stricklin wrote:
On Nov 25, 2007, at 8:04 AM, Michael B. Brutman wrote:
My theory is that your machine is not 'original'. I can't tell you
which card doesn't belong .. there are a few suspects. Many of the 3270
PCs started life as floppy-only units, so the hard disk card might not
be original. Another possibility is that the memory has been upgraded
by replacing the host comm card with the memory/printer card or the
other memory card. Lastly, I'm not sure that this machine needed the
async card, but something tells me that all XT type machines that the
Async adapter in that slot. (Which I think is actually slot 8, not slot
one. There was something special about that slot.)
Anyway, an original 3270 PC (or variant) would have a 3270 emulation
board in it, and that would be connected by coax. The async adapter
would have never worked for that.
The other thing that puzzles me about the mystery card in your machine
and the eBay card is I've never seen one. IBM had a printer port on the
monochrome adapter and on the AT cards there was a parallel port/serial
port card, but I have never seen an IBM card with a parallel port and
memory. But, given the other special cards in that machine and what I
read, it seems like that is what it is.
You need somebody who has a 3270 PC guide to operations or a tech ref.
Mike
I'm digging in my secret archives. I have
just one clue so far -
somebody called it a 'printer/memory' card. Based on your description
of it and this clue, I doubt that it is the comm card for the machine.
This is the same card as mine, right here. I'm not sure I buy the
seller's description of it as a parallel printer card, though it's
certainly possible. I could accept the description if somebody were to
find some other corroborating evidence.
http://cgi.ebay.com/IBM-PC-XT-Parallel-Port-Card-ISA-Parallel-Printer-Card_…
Interestingly, it was also removed from a 5271.
Actually, the more I think about it, the more it makes sense that it's a
parallel card. Would the 5271 have been capable of using the Async
Adapter as a host interface? That's the only remaining I/O card in the
machine.
ok
bear
6:17 p.m.
As there is no 3270 coax card and no open slot to have
once held one,
I suspect that the 3270 host interface is the unknown card in slot 7.
I own IBM SDLC and Bisync adapter cards, and this one doesn't look
like either.
Physical characteristics:
* 8-bit, short card.
* One DB25F on the bulkhead.
* 9x Oki M37S64-20; apparently 64Kx1 memories.
THose aren't piggybacked chips by any chance, are they?
* 34 pin .100" header, vertically, at back end of
card (J2)
* one 4-pos DIP switch at top right.
* Pretty much everything else on the card is 74LS-series TTL or passive.
It's built like IBM made it, but I can't find any obvious IBM-style
part number on it, unless it's 2683541. Google is silent on this
number. (update: I just noticed 6320999 in the etch, but that hasn't
gotten me any closer to an answer).
I know of one card that almost matches that description, except that
there are puggybacked RAMs for a total of 128K. Ans that's a combined
parallel printer card and 128K RAM card (together with 256K on the
motherboard and 256K on the memory card, that would give you the 640K
maximum RAM of a PC/XT system).
I have one here. It says 'PN 6236193' in the silkscreen on the solder
side of the PCB, and has '6236194' in the etch. Otherwise it matches your
description, except that U27 is a delay line (you didn't mention one of
these)
I thought the 3270 host interface was a full-legth card with a BNC socket
on the brakcet and an 8X300-seires microcontroller on it. But I might be
thinking of soemthing else.
-tony
26 Nov
26 Nov
12:37 a.m.
On Nov 25, 2007, at 3:17 PM, Tony Duell wrote:
THose aren't piggybacked chips by any chance, are
they?
I didn't look very closely at first and assumed they were socketed,
but you're right. They are piggybacked.
Otherwise it matches your description, except that U27
is a delay
line (you didn't mention one of these)
I didn't recognize it as a delay line. What I have is a printer/
memory adapter.
The other question remains, however: was it possible to use the Async
Adapter for the 3270 host connection, probably in combination with a
modem of some description? I always assumed that one needed SDLC or
Bisync to do this in the absence of the obvious (coax) interface.
ok
bear
1:48 p.m.
On Sunday 25 November 2007 02:29, r.stricklin wrote:
I am restoring a ca. 1985 IBM 5271---the so-called
3270 PC. I
received it intact, with a full complement of cards, cables, etc. It
looks very much like it was shut down, removed from its original
office installation, and then apparently left somewhere the squirrels
could get to it (thus, "restoring"). I've vacuumed about forty pounds
of sunflower seed hulls out of it. Blessedly, I haven't found any
other signs of animal inhabitation.
This reminds me of the Kaypro I was brought once that had been used in a barn.
I must've pulled ten pounds of straw out of it, which would tend to explain
the disk errors they were getting...
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
6115
days inactive
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days old
12 comments
6 participants
participants (6)
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ard＠p850ug1.demon.co.uk -
bear＠typewritten.org -
chd_1＠nktelco.net -
derschjo＠msu.edu -
mbbrutman-cctalk＠brutman.com -
rtellason＠verizon.net