25 Apr
1999
25 Apr
'99
2:43 p.m.
Yesterday, at the KS10 move, I came away with two IBM PCs, but I
don't know enough about them to know if they are the AT or XT
models... they both have a 5.25" floppy and a hard drive, and
both have color monitors.
They are both desktop boxes... the monitors were sitting on top
of them.
So, how do I tell...
Megan Gentry
Former RT-11 Developer
+--------------------------------+-------------------------------------+
| Megan Gentry, EMT/B, PP-ASEL | Internet (work): gentry!zk3.dec.com |
| Unix Support Engineering Group | (home): mbg!world.std.com |
| Compaq Computer Corporation | addresses need '@' in place of '!' |
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| Nashua, NH 03062 | "pdp-11 programmer - some assembler |
| (603) 884 1055 | required." - mbg |
+--------------------------------+-------------------------------------+
25 Apr
25 Apr
3:18 p.m.
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5:47 p.m.
If it's a clone, the above doesn't apply. Pull the case, and find the CPU
chip (probably on the motherboard). If it's an 8088 or an 8086, it's an
XT clone. If it's an 80286, it's an AT clone.
Unless its a 286 XT ;) In which case it probably has a ribbon cable running
from the cpu socket, connected to a Microsoft Mach 20
board in one of
the expansion slots.
-Lawrence LeMay
26 Apr
26 Apr
4:26 a.m.
> If it's a clone, the above doesn't apply.
Pull the case, and find the CPU
> chip (probably on the motherboard). If it's an 8088 or an 8086, it's an
> XT clone. If it's an 80286, it's an AT clone.
Unless its a 286 XT ;) In which case it probably has a
ribbon cable running
from the cpu socket, connected to a Microsoft Mach 20 board in one of
the expansion slots.
I have to disagree - thats an upgraded XT, but there have been
'true' XT286 from IBM - these are branded as XT or XT286 and
utilize the 286 on the mainboard (AFAIK it has been a special
Mobo revision). I just can't hit the modell number.
Gruss
H.
--
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Ich denke, also bin ich, also gut
HRK
12:56 a.m.
On 26 Apr 99 at 13:27, Hans Franke wrote:
The XT286 model # was the 5162
ciao larry
lwalker(a)interlog.com
Let us know of your upcoming computer events for our Events Page.
t3c(a)xoommail.com
Collectors List and info http://members.xoom.com/T3C
> If
it's a clone, the above doesn't apply. Pull the case, and find the CPU
> chip (probably on the motherboard). If it's an 8088 or an 8086, it's an
> XT clone. If it's an 80286, it's an AT clone.
Unless its a 286 XT ;) In which case it probably
has a ribbon cable running
from the cpu socket, connected to a Microsoft Mach 20 board in one of
the expansion slots.
I have to disagree - thats an upgraded XT, but there have been
'true' XT286 from IBM - these are branded as XT or XT286 and
utilize the 286 on the mainboard (AFAIK it has been a special
Mobo revision). I just can't hit the modell number.
Gruss
H.
10:28 a.m.
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25 Apr
25 Apr
3:46 p.m.
Yesterday, at the KS10 move, I came away with two IBM PCs, but I
don't know enough about them to know if they are the AT or XT
models... they both have a 5.25" floppy and a hard drive, and
both have color monitors.
They are both desktop boxes... the monitors were sitting on top
of them.
So, how do I tell...
Megan Gentry
Former RT-11 Developer
Real IBM AT's also had a cover over the screws and back case end held on
by velcro to pretty it up.
The PC's didn't. I don't think the XT's did either.
I've got a spare if anyone's restoring an AT to that kind of mint
condition.
Price -- shipping +$5.00.
Bill
4:51 p.m.
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5:10 p.m.
Real IBM
AT's also had a cover over the screws and back case end held on
by velcro to pretty it up.
Except that that cover is almost always missing after all these years. I
don't think I've ever seen a PC/AT with it still in place. The PC's
didn't. I don't think the XT's did either.
No, the XT is a very similar case to the PC and doesn't have this cover.
-tony
4:20 p.m.
Upon the date 07:43 PM 4/25/99 -0400, Megan said something like:
Yesterday, at the KS10 move, I came away with two IBM PCs, but I
don't know enough about them to know if they are the AT or XT
models... they both have a 5.25" floppy and a hard drive, and
both have color monitors.
They are both desktop boxes... the monitors were sitting on top
of them.
So, how do I tell...
Hi Megan, tell us the model numbers found on the back label (5150 for
example) and report back. Someone will peg them for ya . . .
Regards, Chris
-- --
Christian Fandt, Electronic/Electrical Historian
Jamestown, NY USA cfandt(a)netsync.net
Member of Antique Wireless Association
URL: http://www.ggw.org/awa
8:36 p.m.
Megan wrote:
Yesterday, at the KS10 move, I came away with two IBM PCs, but I
don't know enough about them to know if they are the AT or XT
models... they both have a 5.25" floppy and a hard drive, and
both have color monitors.
IBM PC - 5 slots, 8 bit card connectors, 63.5 watt P/S, 0 - 2 360K floppy
disk drives, 4116 or 4164 memory chips depending on motherboard, and a
maximum of 256K RAM on the motherboard. The keyboard does not include
separate cursor keys. The front nameplace will have IBM Personal Computer on
it.
IBM XT - 8 slots, 8 bit card connectors (one connector per slot), 150 watt
P/S, 1 or 2 360K floppy disk drives, Hard disk, can't recall memory chips
but I believe 4164 up to 256K RAM on motherboard, same keyboard as the PC.
The front nameplate will have IBM Personal Computer XT on it.
IBM AT - 8 slots, 16 bit card connectors (two connectors per slot), IIRC 200
watt P/S, 1 or 2 floppy drives: if one, then 1.2 MB Floppy disk, if two,
could be one 1.2 MB floppy and one 360K, or two 1.2 MB drives, up to 512K
RAM of 41256 chips on motherboard (early ones used piggy back chips), AT
keyboard with separate cursor keys. Can't recall what the front nameplate
has on it, but the case (besides being bigger than the XT case) has an
additional reset switch, keylock switch, and "power on" LED on the front
panel.
Modifications can change the above configurations, and one of the common
mods was to put a hard drive in a PC by replacing the P/S with a 150 watt
P/S and adding the HD controller. Clone PC/XT cases could also have the same
front panel switches as the IBM AT. Lots more possibilities but I think this
takes care of the most common cases (pun intended :) .)
26 Apr
26 Apr
7:40 a.m.
additional reset switch, keylock switch, and
"power on" LED on the front
^^^^^^^^^^^^
NO!!!!!
Any responsible computer manufacturer of the time included a reset switch.
But we are talking about IBM.
THERE WAS NO RESET SWITCH ON A REAL UNMODIFIED IBM AT.
Minor quibble: was the XT power supply 135W?
On Sun, 25 Apr 1999, Marvin wrote:
> Megan wrote:
> >
> > Yesterday, at the KS10 move, I came away with two IBM PCs, but I
> > don't know enough about them to know if they are the AT or XT
> > models... they both have a 5.25" floppy and a hard drive, and
> > both have color monitors.
>
> IBM PC - 5 slots, 8 bit card connectors, 63.5 watt P/S, 0 - 2 360K floppy
> disk drives, 4116 or 4164 memory chips depending on motherboard, and a
> maximum of 256K RAM on the motherboard. The keyboard does not include
> separate cursor keys. The front nameplace will have IBM Personal Computer on
> it.
>
> IBM XT - 8 slots, 8 bit card connectors (one connector per slot), 150 watt
> P/S, 1 or 2 360K floppy disk drives, Hard disk, can't recall memory chips
> but I believe 4164 up to 256K RAM on motherboard, same keyboard as the PC.
> The front nameplate will have IBM Personal Computer XT on it.
>
> IBM AT - 8 slots, 16 bit card connectors (two connectors per slot), IIRC 200
> watt P/S, 1 or 2 floppy drives: if one, then 1.2 MB Floppy disk, if two,
> could be one 1.2 MB floppy and one 360K, or two 1.2 MB drives, up to 512K
> RAM of 41256 chips on motherboard (early ones used piggy back chips), AT
> keyboard with separate cursor keys. Can't recall what the front nameplate
> has on it, but the case (besides being bigger than the XT case) has an
additional reset switch, keylock switch, and
"power on" LED on the front
> panel.
>
> Modifications can change the above configurations, and one of the common
> mods was to put a hard drive in a PC by replacing the P/S with a 150 watt
> P/S and adding the HD controller. Clone PC/XT cases could also have the same
> front panel switches as the IBM AT. Lots more possibilities but I think this
> takes care of the most common cases (pun intended :) .)
4:23 a.m.
Date: Mon, 26 Apr 1999 09:40:16 -0700 (PDT)
Reply-to: classiccmp(a)u.washington.edu
From: "Fred Cisin (XenoSoft)" <cisin(a)xenosoft.com>
To: "Discussion re-collecting of classic computers"
<classiccmp(a)u.washington.edu>
Subject: Re: PC question
X-To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
NO!!!!!
Any responsible computer manufacturer of the time included a reset switch.
But we are talking about IBM.
THERE WAS NO RESET SWITCH ON A REAL UNMODIFIED IBM AT.
That's the beef with many machines even we had to add one to a 1 year
old PII from gateway. (!!) Resetting by power cycles is VERY hard
on all parts including wearing out HD fast. I see that same effect
on early laptops HDs that was constantly spinning up/down on demand.
Minor quibble: was the XT power supply 135W?
I think bit smaller than that. I Know it's not 63W. Upgrade was
135W or 180W not sure for offical IBM upgrade.
Many IBM PC PSUs were made by Zenith, I can tell.
My favorite is ones with sloped fan behind protective stamped
grilles. Also these IBM PSUs always have ball bearing fans which is
big boon! :-)
Wizard
email: jpero(a)cgocable.net
Pero, Jason D.
10:48 a.m.
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3:08 p.m.
On Mon, 26 Apr 1999, Tony Duell wrote:
I've seen several different AT PSUs from IBM. One
of them is certainly a
Gresham Lyons design.
Are all of the PSU models documented in the technical manuals? Are they
radically different or basically clones?
--Max Eskin (max82(a)surfree.com)
http://scivault.hypermart.net: Ignorance is Impotence - Knowledge is Power
5:26 p.m.
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8:19 a.m.
"Fred Cisin (XenoSoft)" wrote:
Ah yes, call it a senior moment :), and yes on both counts. Now that you
mention it, I can't recall if there was even a reset connection on the AT
motherboard. Somehow the 150 watt P/S didn't sound quite right, but I was a
bit tired and didn't give it enough thought.
additional reset switch, keylock switch, and
"power on" LED on the front
^^^^^^^^^^^^
NO!!!!!
Any responsible computer manufacturer of the time included a reset switch.
But we are talking about IBM.
THERE WAS NO RESET SWITCH ON A REAL UNMODIFIED IBM AT.
Minor quibble: was the XT power supply 135W?
3:04 p.m.
On Mon, 26 Apr 1999, Fred Cisin (XenoSoft) wrote:
NO!!!!!
Any responsible computer manufacturer of the time included a reset switch.
But we are talking about IBM.
THERE WAS NO RESET SWITCH ON A REAL UNMODIFIED IBM AT.
Well, the C-64 had no reset switch...or are we talking only about business
systems? My DECMate III has no reset switch.
--Max Eskin (max82(a)surfree.com)
http://scivault.hypermart.net: Ignorance is Impotence - Knowledge is Power
10:35 a.m.
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9220
days inactive
9221
days old
18 comments
11 participants
participants (11)
-
ard＠p850ug1.demon.co.uk -
cfandt＠netsync.net -
cisin＠xenosoft.com -
Hans.Franke＠mch20.sbs.de -
jpero＠pop.cgocable.net -
lemay＠cs.umn.edu -
lwalker＠mail.interlog.com -
marvin＠rain.org -
max82＠surfree.com -
mbg＠world.std.com -
pechter＠pechter.dyndns.org