20 May
2025
20 May
'25
3:15 p.m.
I just managed to score a 5155. Well, soon, it is waiting for me to
pick it up at the University where I used to work. It looks to be in
really good shape and has been in storage for probably two decades or
more.
A couple quick question for anyone familiar with this system.
Is it likely there is one of those little batteries on it that would
now be dead and need replacing before I try to use it?
And, also, would this have a floppy controller on it that was capable
of reading and writing disks from systems like the TRS-80 with an SD
boot track?
Inquiring minds want to know. :-)
bill
20 May
20 May
3:32 p.m.
Is it likely there is one of those little batteries on
it that would
now be dead and need replacing before I try to use it?
If it has a battery, it'd be on an add-on board, so check to make sure there
aren't leakers, but otherwise no.
Your more likely issue will be shorted tantalums. It's a 256K XT motherboard in
there.
And, also, would this have a floppy controller on it
that was capable
of reading and writing disks from systems like the TRS-80 with an SD
boot track?
Almost certainly no, if it has the external floppy connector (37-pin D-SUB). There were
third party controllers that will.
Thanks,
Jonathan
3:53 p.m.
And, also, would this have a floppy controller on
it that was capable
of reading and writing disks from systems like the TRS-80 with an SD
boot track?
Almost certainly no, if it has the external floppy connector (37-pin
D-SUB). There were third party controllers that will.
3:45 p.m.
It’s an IBM XT with a built-in monochrome display. No battery on the
motherboard unless someone added an expansion card that required a battery.
On Tue, May 20, 2025 at 9:38 AM Bill Gunshannon via cctalk <
cctalk(a)classiccmp.org> wrote:
I just managed to score a 5155. Well, soon, it is waiting for me to
pick it up at the University where I used to work. It looks to be in
really good shape and has been in storage for probably two decades or
more.
A couple quick question for anyone familiar with this system.
Is it likely there is one of those little batteries on it that would
now be dead and need replacing before I try to use it?
And, also, would this have a floppy controller on it that was capable
of reading and writing disks from systems like the TRS-80 with an SD
boot track?
Inquiring minds want to know. :-)
bill
3:51 p.m.
On Tue, May 20, 2025 at 2:38 PM Bill Gunshannon via cctalk
<cctalk(a)classiccmp.org> wrote:
I just managed to score a 5155. Well, soon, it is waiting for me to
pick it up at the University where I used to work. It looks to be in
really good shape and has been in storage for probably two decades or
more.
I restored one last year. Mine is still 100% orginal IBM too.
It's a normal PC/XT motherboard with CGA and floppy controller boards
at least. Technical references for everything apart from the power
supply are on bitsavers. Theres another site with some detailed
information on the power supply and I think I found the sources for
the keyboard microcontroller as a Github project.
A couple quick question for anyone familiar with this system.
Is it likely there is one of those little batteries on it that would
now be dead and need replacing before I try to use it?
No, it's a XT, so no internal real time clock or CMOS configuration
RAM as standard.
What you do need to replace before they do their antisocial acts and
emit clouds of magic smoke are the metalised paper capacitors in the
power supply. This is painful to do, you have to dismantle the power
supply which involves Bristol Spline and tamperproof Torx screws, then
drill out rivets holding the little filter PCB in place. Rivets that
are hard to get a drill to.
The only other part I had to replace in mine was a tantalum bead
capactor on the motherboard.
And, also, would this have a floppy controller on it that was capable
of reading and writing disks from systems like the TRS-80 with an SD
boot track?
Alas not. The oriignal IBM controller is strictly double density (MFM) only.
-tony
5:16 p.m.
On Tue, 20 May 2025, Bill Gunshannon via cctalk wrote:
I just managed to score a 5155. Well, soon, it is
waiting for me to
pick it up at the University where I used to work. It looks to be in
really good shape and has been in storage for probably two decades or
more.
A couple quick question for anyone familiar with this system.
Is it likely there is one of those little batteries on it that would
now be dead and need replacing before I try to use it?
It is a 5160 (IBM PC/XT) is a different case. Luggable, like an original
Compaq, although most people feel that Compaq did a better job of
converting to a aluggable, specifically including how much of how many
slots remain fully accessible. It was most likely created BECAUSE of the
success of the original Compaq.
Colby? created an after-market case for 5150, that was smaller than
Compaq.
The 5150/5160/5155 had no real time clock. IBM didn't include that until
the 5170 (PC/AT). But there were MANY third party multi-function boards
the included addition of a real-time clock, so those need to be examined
for leakage, etc.
And, also, would this have a floppy controller on it
that was capable
of reading and writing disks from systems like the TRS-80 with an SD
boot track?
Short answer: NO.
It could, with appropriate added software, read and write MANY DD/MFM
disks from other machines, including:
http://www.xenosoft.com/fmts.html
but NOT SD/MFM. And even boards that could, and the TRS80 model 3/4 had
difficulty with the "non-standard" DAMs (Data Address Marks) used on TRS80
model 1. There used to be an unconfirmed explanation saying that the
choice(s) of DAMs for the model 1 was due to a misprinted 765 spec sheet,
with 2 columns transposed.
The 5150/5160/[5155] FDC board used an NEC 765 (or equivalent) that was
hard wired for DD/MFM. In stock configuration, it did not permit SD/FM,
although it certainly could have been modified (non-trivially) for such.
Similarly, Flagstaff Engineering modified those FDC boards (quite a few
added wires), with added software, for 8" SSSD CP/M; but not 5/25" SD/FM.
Marty Goodman studied one, and copied those changes, to modify a few
imitations; but he no longer has any of them, nor his notes from the
project, and likely doesn't even remember doing it.
OB_Tangent: Sorrento Valley Associates made a floppy controller card for
the Apple2 that used an FDC chip, in order to be able to do 8" SSSD CP/M.
There were numerous third party FDC boards thet could do SD/FM, some of
which used the WD37C65 chip. David Dunfield provided a small program
that could test 5150/5160/[5155] and other PC FDC's for whether they could
handle SD/FM.
Inquiring minds want to know. :-)
The National
Enquirer (who made popular the phrase: "Inquiring minds want
to know") had little or no coverage of microcomputers. THOSE inquiring
minds did not want to know.
--
Grumpy Ol' Fred cisin(a)xenosoft.com
http://www.xenosoft.com
5:29 p.m.
On Tue, 20 May 2025, Fred Cisin via cctalk wrote:
Colby created an after-market case for 5150, that was
smaller than Compaq.
https://vintage-computer.fr/tag/colby/
21 May
21 May
2:33 a.m.
I still can't figure out why replies sent through my android phone to the list lose
formatting...
Is it likely there is one of those little batteries on
it that would
now be dead and need replacing before I try to use it?
Congrats and no. This is your std XT (5160) MB just shoved in a case with a handle and
monitor.
And, also, would this have a floppy controller on it
that was capable
of reading and writing disks from systems like the TRS-80 with an SD boot track?
If it works on an XT it will work on a 5155. If not then no.
-Ali
3:35 a.m.
New subject: formatting (Was: IBM 5155
On Tue, 20 May 2025, Ali via cctalk wrote:
I still can't figure out why replies sent through
my android phone to the list lose formatting...
At first glance, it looks as though your "newline"s are not being
recognized as such.
Were you using any other formatting, in addition to newline?
"Newline", on various systems, can be CR (Carriage Return), LF (Line
Feed), CRLF, or LFCR. In printers, many did an automagic LF whenever they
got a CR, etc.
For a while, each system insisted that theirs was the only true way, and
that everybody else shoulc change to match them.
The copy of your first 5155 post that I get from the list has no newlines.
So, whatever software you are using on your phone seems to be sending
sonething for newline, that the list server isn't recognizing.
I'm sorry that I can't be any real help, but that is what the nature of
the problem seems to be.
--
Grumpy Ol' Fred cisin(a)xenosoft.com
4:43 a.m.
New subject: formatting (Was: IBM 5155
At first glance, it looks as though your
"newline"s are not being
recognized as such.
That would be accurate. I went so far as putting in two blank lines to see
if only one was being discarded for some reason.
Were you using any other formatting, in addition to
newline?
No. It is a simple text reply.
The copy of your first 5155 post that I get from the
list has no
newlines.
So, whatever software you are using on your phone seems to be sending
sonething for newline, that the list server isn't recognizing.
Yes. I am using the stock Samsung email program that comes preinstalled on
their phones. It seems to be only the list server that fails. i.e. sending
email to other people on different system/servers/providers using a variety
of email readers on multiple OSes works fine. Only when I reply to the list
does this issue occur.
I'm sorry that I can't be any real help, but
that is what the nature of
the problem seems to be.
NP. Thanks for chiming in!
-Ali
11:08 a.m.
New subject: formatting (Was: IBM 5155
At first glance, it looks as though your
"newline"s are not being
recognized as such.
That would be accurate. I went so far as putting in two blank lines to see
if only one was being discarded for some reason.
Were you using any other formatting, in addition
to newline?
No. It is a simple text reply.
The copy of your first 5155 post that I get from
the list has no
newlines.
So, whatever software you are using on your phone seems to be sending
sonething for newline, that the list server isn't recognizing.
Yes. I am using the stock Samsung email program that comes preinstalled on
their phones. It seems to be only the list server that fails. i.e. sending
email to other people on different system/servers/providers using a variety
of email readers on multiple OSes works fine. Only when I reply to the list
does this issue occur.
9:04 p.m.
New subject: formatting (Was: IBM 5155
When sending, most email clients, likely including this Samsung thing,
create emails in two sections. One section is formatted using HTML
(to accomodate the dancing kangaroos and yodelling jellyfish which Fred
occasionally refers to) and the other is formatted in plain text.
...
The Samsung email client thing produces broken plain
text formatted
sections
in its outgoing emails. Most recipients don't notice the problem
because
their email client picks the HTML section and presents this to them
instead
and this looks ok.
Peter,
Thanks for the detailed explanation. That would make sense and sounds very
likely. I will send a report to Samsung but I really doubt they will care or
fix it. It will probably be easier for me to just get a separate client,
that handles text only messages properly, on android and use that for the
list.
-Ali
1
days inactive
2
days old
11 comments
7 participants
participants (7)
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Ali -
Bill Degnan -
Bill Gunshannon -
Fred Cisin -
Jonathan Chapman -
Peter Coghlan -
Tony Duell