IBM Model M: Question regarding quality of manufacturer

[mcc]

Hello,

This is my first posting to this forum. First of all: I am no native
English speaker...if something written by me sounds harsh, unfriendly
or simply wrong - it is *by far* not my intention.

My IBM Model M is a 1391403 (QWERTZ) made 1997 by IBM, Scotland Greenock. It has
a fixed PS2 cable, drainage holes, a simple LED panel (not dark color around it) and removable
keycaps. The Logo is on the left side, made of plastik with blue letters on a grey ground.
The keyboard processor is made by Lexmark and it sits on a PCB labeled (also printed the way
as the conductive cupper layer is made) with the letters "IBM". The PCB carries the LEDs also and sits
right below the LED panel. The non coiled cable is about  182.2cm long and the keyboard weigths
ariound 2.2kg. It has an internal metal rounded plate  on which the whole mechanism sits. The label on
the back is made of the same gre plastik folio as the IBM logo (without the logo itsself of course!
and has two signatures for "(I)" and "(QA)" ... (I) = "Inspection, (QA) for "Quality Assurance"

Previously I contacted Brandon Ermita of clickykeyboards to help me to identify
my keyboard, since my previously """knowledge""" about the "Big M" together
with the data I had of my board had totally confused me. Brandon was very helpful
and friendly and I want to thank him very much again this way.

Brandon talks of technical differences between Lexmark-made, IBM-made, Unicomp-made,
early-made and later-made "Model M"s.

Since I have no way to compare more keyboards directly ("more keyboards" would be the heaven
to me I would be interested in the technical details of these differences and the differences
of quality of the boards.

Unfortunately I find contradictionary posts: One say "The only one true keyboard is
made by IBM USA and it is " ... other say: There are no
differences as long the keyboard has buckling springs. Totally different posts say:
"There are no differences in keyboards at all!" (ok, last one is not meant seriously

What are those technical details and what is the impact to my keyboard regarding these
differences?

Thank you very much in advance for any help !
Best regards
mcc

[Ascaii]

I can give you some info, but the person that can help you out the most is Ch_123. On thing found specifically on the greenock boards is the grounding clip and wire under the spacebar. As for other differences, the 1390133 (German version of the 130131, just as the 1391403 is a german version of the 1391401), has a stabilizer on the enter key different from later versions. As I have yet to try out a lexmark model M i can't tell you more about those, all I have are 1390133,1390131, 1391403, 1391401 boards at the moment. If youre looking for any DE layout vintage mechs hit me with a pm, i usually have a bunch of old Ms and cherry g80s lying around to sell for a little bit of cash.

[ch_123]

The Greenock made ones have an electric grounding wire on the spacebar (if you pop it off you can see it connected to the underside) and on the ones made post 1992, they have drainage holes on the underside, but not the drainage channels inside the keyboard like the US and Mexican made ones did.

Check out the IBM Wiki. In particular, the "Are older Model Ms better than newer ones?" section. Your keyboard would probably correspond to a 42H1292, which was the contemporary US layout keyboard.

As for other differences, the 1390133 (German version of the 130131, just as the 1391403 is a german version of the 1391401), has a stabilizer on the enter key different from later versions.

All Model Ms made before '88 or '89 had stabilizer bars on the vertical keys. Then they came up with a way of doing the stabilizer free insert on those keys (it's actually different to the ones used on horizontal keys)