deskthority

Does anyone have any idea what "Plt No" on Model M/F stickers means? Plate number? Plant number? And do we have any idea what the codes like F1 refer to?

Plant, I think. Lots came out of F1 over in America.

Chyros wrote: Does anyone have any idea what "Plt No" on Model M/F stickers means? Plate number? Plant number? And do we have any idea what the codes like F1 refer to?

Similar codes have been used by IBM in newer serial numbers, 'Plt No' should be similar (plant and some additional information).

IBM Global Labeling Guide Volume 5 - Part Labels wrote: J1 Identifies the plant (location) of control of the S/N header and the part ‘type’ (new, used, internal-use-only,
etc.). The letter indicates the location, and the number indicates the type. Letter-number and number-letter pairs indicate different labs. For example:
J1 - Location (Plant) of Control: Raleigh, type: New
L1 - Location of Control: Rochester, type: New
A1 - Location of Control: Austin, type: New
7J - Location of Control: Greenock, type: Used
Other 2-digit numeric or 2-character alphabetic codes are assigned to OEM subcontractors.
See http://w3-9006.ibm.com/isc/distribution ... +loc+codes for the
complete list of codes.

[IBM Global Labeling Guide Volume 5 - Part Labels, Page 26] http://www-03.ibm.com/procurement/prowe ... uide_5.pdf

ReleaseCandidate wrote:

Chyros wrote: Does anyone have any idea what "Plt No" on Model M/F stickers means? Plate number? Plant number? And do we have any idea what the codes like F1 refer to?

Similar codes have been used by IBM in newer serial numbers, 'Plt No' should be similar (plant and some additional information).

IBM Global Labeling Guide Volume 5 - Part Labels wrote: J1 Identifies the plant (location) of control of the S/N header and the part ‘type’ (new, used, internal-use-only,
etc.). The letter indicates the location, and the number indicates the type. Letter-number and number-letter pairs indicate different labs. For example:
J1 - Location (Plant) of Control: Raleigh, type: New
L1 - Location of Control: Rochester, type: New
A1 - Location of Control: Austin, type: New
7J - Location of Control: Greenock, type: Used
Other 2-digit numeric or 2-character alphabetic codes are assigned to OEM subcontractors.
See http://w3-9006.ibm.com/isc/distribution ... +loc+codes for the
complete list of codes.

[IBM Global Labeling Guide Volume 5 - Part Labels, Page 26] http://www-03.ibm.com/procurement/prowe ... uide_5.pdf

Cheers dude; unfortunately, the list seems to be down. My two '1406s appear (the sticker is different) to have Plt No F2 and L5 respectively; but they were both made in the UK (I thought Greenock made all the UK Ms? Oo ). My US-made 1370477 has Plt No TC1. Do we know anything about these codes?

I'm also trying to find out what the Plt No for one of my unlabelled Ms was; a grey-badge '1406 from '87 I bolt-modded ages ago. Any idea what it might've been?

Chyros wrote: Cheers dude; unfortunately, the list seems to be down.

The link (http://w3-9006.ibm.com/isc/distribution ... +loc+codes) is an internal IBM one and not valid for older (pre 2000 IIRC) parts anyway.

Found this post searching because I have the same question. Did you ever figure it out?

I like interesting topics.

Finding the labeling guides is pretty easy, but, as mentioned above, it's probably not accurate for pre-2000 devices.

This Geekhack thread asked about the "Plt No", too, and IBM's official response was "dunno." (I recommend reading the whole thread. Lots of good info.)

Take a look at this, which categorizes only a couple versions of the Model M. For the 1391041, one of the largest groupings is F, like F1, F2, F4, F7, F8, and F9. Of that, I think F2 has the largest share. It also lists up until 1994. Late 1993 was the Lexmark "buyout."

ClickyKeyboards.com mentions ...

Possibilities include
1. Plt might refer specific keyboard sub-assembly or production materials list that was used
2. Plt might refer to something like the individual who supervised the assembly process
3. Plt might be the specific market segment the original IBM ps/2 computer and keyboard was intended for (large enterprise, public sector, small/medium business, higher education)

Another theory would be it's an assembly line within a specific plant, e.g. "J" for Lexington, "4" for assembly line 4.

I have suspected that they might have had something to do with the factory keycaps. Been a while since I looked closely at one, but I believe the blue sub legend model F122’s have a unique PLT No, though part number was the same as other models in some cases. You’d have to get a good sample size of stickers compared to caps to see if there’s a pattern there and be fairly certain that the caps weren’t switched at some point. 3178’s for example have 4 different types of caps, but I believe they all say PLT 23, though they are unique in that they have a MOD number that describes the keycaps on them instead.

hellothere wrote: 18 Jan 2021, 01:31 This Geekhack thread asked about the "Plt No", too, and IBM's official response was "dunno." (I recommend reading the whole thread. Lots of good info.)

That was an interesting read- thanks for sharing!

orihalcon wrote: 18 Jan 2021, 21:55 I have suspected that they might have had something to do with the factory keycaps. Been a while since I looked closely at one, but I believe the blue sub legend model F122’s have a unique PLT No, though part number was the same as other models in some cases. You’d have to get a good sample size of stickers compared to caps to see if there’s a pattern there and be fairly certain that the caps weren’t switched at some point. 3178’s for example have 4 different types of caps, but I believe they all say PLT 23, though they are unique in that they have a MOD number that describes the keycaps on them instead.

I recently happened upon a PS/2 square badge M122 with the F122-style double flippers, stepped caps, and blue legends. It is a 1393656, has Plt F1, and reports itself as being made in the USA in '89. Haven't found too much about this particular part number but it has an unusual set of attributes.