Another AT Model F, $30

[Manyak]

http://cgi.ebay.com/IBM-PERSONAL-COMPUTER-1801449-83-CLICKY-KEY-KEYBOARD_W0QQitemZ390067636888QQcmdZViewItemQQptZPCA_Mice_Trackballs?hash=item5ad1d7ca98&_trksid=p3286.c0.m14&_trkparms=65%3A1|66%3A2|39%3A1|293%3A3|294%3A50

[Hak Foo]

NOT an AT F.  It's clearly an XT by the layout and lack of lamps.

I wonder if putting an AT-> PS/2 adaptor on such a board would work on a PS/2 model 25 or 30 (analogous to an XT)

[Manyak]

oopsies!

I hope whoever bought it has an XT->AT adapter.

[ch_123]

I wonder if putting an AT-> PS/2 adaptor on such a board would work on a PS/2 model 25 or 30 (analogous to an XT)

I've never heard of an XT keyboard with a PS/2 connector... I'm pretty sure those PS/2s probably used the AT scancodes, even if their basic spec was similar to the original PC/XT.

[Manyak]

I've never heard of an XT keyboard with a PS/2 connector... I'm pretty sure those PS/2s probably used the AT scancodes, even if their basic spec was similar to the original PC/XT.

It's not just the scancode that differs, it's the entire protocol. Everything from the number of bits per packet to the timing of data line reads (AT reads on clock high, XT reads on clock low....or the other way around but they are still opposite).

[timw4mail]

It's not just the scancode that differs, it's the entire protocol. Everything from the number of bits per packet to the timing of data line reads (AT reads on clock high, XT reads on clock low....or the other way around but they are still opposite).

Which the conversion, no doubt adds a few milliseconds to the key response time. Anyone use an XT with an adapter?

[ch_123]

It's not just the scancode that differs, it's the entire protocol. Everything from the number of bits per packet to the timing of data line reads (AT reads on clock high, XT reads on clock low....or the other way around but they are still opposite).

Yeah... I meant that but was too lazy to spell it out in it's entirety I stand by my point though - I think IBM made those 8088-equipped PS/2s with the modern AT protocol - I'm pretty sure those LED-less Model Ms were AT compatible.

[Manyak]

Yeah... I meant that but was too lazy to spell it out in it's entirety I stand by my point though - I think IBM made those 8088-equipped PS/2s with the modern AT protocol - I'm pretty sure those LED-less Model Ms were AT compatible.

The LED-less Model Ms (1390120) were AT, I don't think the M was ever made XT.

[ch_123]

Well there you go, plugging an XT into a PS/2 will not work, even if the spec is otherwise similar to that of a PC or PC/XT

[Mercen_505]

Build-wise, there is a pretty huge difference between the XT and AT model F keyboards. Now that I have both, I can see that the AT board is pretty shoddy in comparison. I guess I need to take some pics to properly explain it, but although the layout sucks, I prefer the XT's superior build quality. I'm typing this up on my AT model F now... at least it works!

[ch_123]

The idea that there's something even more over-built than the AT Model F is somewhat frightening to be hoenst . That said, when I saw some youtube videos of the original IBM PC, I noticed how the keyboard made a much more satisfying snap than that of my AT Model F. I wonder how the Model F terminal boards were in comparison...

[Mercen_505]

The model F XT I have is like a freaking brick -- rock solid and there is absolutely no flex to the board whatsoever. The keys sit neatly centered in the openings on the top of the frame, and don't have much 'wobble' to them (take a key and try to turn it like a knob) except for the double height keys on the right side... which wobble like crazy.

The Model F AT I got recently is of significantly cheaper build. The board itself has a little flex to it, and it has cheap (and small!) rubber nubs on the bottom to hold it in place. The keys are off center, tend to wobble in their seatings, and there is a lot of flash on the top of the case, especially in the tabs that go between the spacebar and the caps lock/alt keys. The casing seems to be a gray material that has a cream colored coat on it, and excessive wear eventually reveals this. What I thought was a dirty spot was actually the gray color showing through! Whoops

There is always the possibility that I got a shoddy piece. As it stands I'm pretty disappointed with it compared to my (admittedly useless) XT board.

[timw4mail]

The model F XT I have is like a freaking brick -- rock solid and there is absolutely no flex to the board whatsoever. The keys sit neatly centered in the openings on the top of the frame, and don't have much 'wobble' to them (take a key and try to turn it like a knob) except for the double height keys on the right side... which wobble like crazy.

The Model F AT I got recently is of significantly cheaper build. The board itself has a little flex to it, and it has cheap (and small!) rubber nubs on the bottom to hold it in place. The keys are off center, tend to wobble in their seatings, and there is a lot of flash on the top of the case, especially in the tabs that go between the spacebar and the caps lock/alt keys. The casing seems to be a gray material that has a cream colored coat on it, and excessive wear eventually reveals this. What I thought was a dirty spot was actually the gray color showing through! Whoops

There is always the possibility that I got a shoddy piece. As it stands I'm pretty disappointed with it compared to my (admittedly useless) XT board.

Does the Model M still seem cheap in comparison to the Model F?

[Mercen_505]

Does the Model M still seem cheap in comparison to the Model F?

Depends. I've got several silver label Ms that are of excellent quality; certainly the only thing they lack compared to an F (XT) is weight! I also have a few blue label Ms that are... not nearly as nice.

[Mercen_505]

Dunno. Having worked for several equipment manufacturers over the years, I can safely say "Things change." Build quality can fluctuate significantly over time based on availability of materials, changing specs in a subtle way to save money or suit customer needs, or at the whim of a penny-pinching purchasing agent. It wasn't unusual to experiment with alternative parts for a few months, then return to the old stuff when things didn't work out as planned, or the pricing changed.

[Mercen_505]

I really need to have a micrometer but early results indicate this whole Blue Label/Black Label thing is bogus. The Unicomp on the other hand....

Measurement of plastic isn't exactly enough. The composition of the plastic is also important, and likely to change over time. My two silver labels are a 1390120, and 1390131. My two blues are 1391401s.

[Mercen_505]

I take that back. One blue is a 401, the other is something else -- I think.

[Mercen_505]

I can give you a full inventory when I get home. I know I have one IBM made blue, and one Lexmark blue... two IBM silvers... a lexmark m4, a unicomp m4, three M2s, and some other odds and ends (industrial, model F, yadda yadda)

I need to take some pics, but my camera is a bit on the ****e side.

[Manyak]

If it's any help I've got a Silver/Black 301, Blue 401, and Black NIB 401. All IBMs.

There's really nothing remarkably different about any of them other than the 301 having stiffer keys and thicker, rounder lettering. And it feels a bit heavier than the other two, though the sturdiness is about the same.

But between the two 401's the only difference that stands out is the key feel, but I'm almost positive it's because one is used and the other is still brand new.

[Mercen_505]

Whee... I'm taking inventory right now. I've got just over 100 pictures to sort and crop, showing various angles of all my boards as well as the labels on the back and any noteworthy attributes. I'll try to go through some of them at work tomorrow; I know I won't finish up tonight!

None of my boards are NIB, but I have several that are barely used.

[timw4mail]

If it's any help I've got a Silver/Black 301, Blue 401, and Black NIB 401. All IBMs.

There's really nothing remarkably different about any of them other than the 301 having stiffer keys and thicker, rounder lettering. And it feels a bit heavier than the other two, though the sturdiness is about the same.

But between the two 401's the only difference that stands out is the key feel, but I'm almost positive it's because one is used and the other is still brand new.

I only have one Model M, but does your Model M have kind of a "muffled" click compared to the Model F? (I'm not really asking you, Manyak )

[timw4mail]

OK, I opened up the whole Black/Grey/Blue Model M debate here.

If somebody is willing to open up let's say a late 80's vintage Model M we can nail this down once and for all.  Grab a scale and a Vernier/Micrometer if you have one.

I have one, but I'm not too willing to open it at this point. I also don't have the tools...

[Manyak]

I'd do it but I don't have a scale or micrometer.

[microsoft windows]

I've opened my blue M up a few times but I don't have any other M's to compare it to.

[microsoft windows]

Well, any model M will get the job done fine. Personally, if I was to buy another, I'd get a blue-label one because it's $40 cheaper just to have your keyboard dry out more easily when something spills on it.

[Mercen_505]

Sorry; been busy today. But that's okay, my 1391 is on loan to my father, and I'll be getting it back next weekend. Then I can start some proper testing, whatever that turns out to be

[keyb_gr]

None of my UK-made Ms seem to have ABS cases. At least my 1991 sample had a yellowed space bar and logo but the case looks unimpressed. So PVC it is then. Good to know.

Speaking of materials, Czech-made Cherry keycaps actually say PBT underneath.

[ch_123]

Polycarbonate/ABS mix.

I'm going to go change Wikipedia Model M entry to read,
"A classic board except for Greenock UK units.  IBM engaged in dumping carcinogenic cheap plastic versions.  Coverup in progress - see Google Earth image".

Was your M4 made in Greenock?