IBM Model M13

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Model Years Manufacturer Notes
13H6705 1994-1998 Lexmark, MaxiSwitch Offered as Stealth Black / Raven Black.
06H4173 1996-1999 MaxiSwitch, Unicomp (for IBM) Industrial (gray) version
82G3281 1994-1995 Lexmark Beige, PS/2 Passthrough, Lowest Known Serial: 0006037
82G3282 1996-1998? MaxiSwitch Identical to 82G3281, shares OPN with 82G3281 spare, research ongoing.
92G7461 1996-1998 MaxiSwitch Branded TrackPoint II; Beige, PS/2 Passthrough, all serials appear to have prefix "311" and "321"

Identifying M13's By Serial

At no point did IBM manufacture the Model M13 in house, and manufacturers were assigned specific serial number batches and prefixes.

  • 13H6705: MaxiSwitch uses prefix "M3n" based on production year. Looking for information on Lexmark prefixes.
  • 06H4173: MaxiSwitch uses prefix "MOOR", Unicomp uses prefix "U000"
  • 82G3281: Lexmark prefixes are "000n", exact format not known.
  • 82G3282: MaxiSwitch uses prefix "FRU" for these keyboards with an unknown format.
  • 92G7461: All serials appear to be prefixed with "301", "311", or "321" for 1996, 1997 and 1998 respectively.

Looks Like M13 But Actually Isn't!

  • IBM Model M4-1 (84H8566) - manufactured exclusively by Unicomp; resembles SSK but is not!
  • IBM KPD8923, FRU 04K0500, OPN 01K1219 - Rubber dome version of Unicomp EnduraPro.

General Information

The IBM Model M13 is a fairly uncommon example of the Model M. The M13 was created by attaching an IBM TrackPoint or TrackPoint II to the barrel plate between the G, H and B keys. The cabling was taken from the IBM Model M5-2 and a new controller was designed which incorporated both the TrackPoint controller as well as PS/2 pass-through capability. The M13 was designed by MaxiSwitch for IBM under contract, and most M13s were built by MaxiSwitch for IBM including the TrackPoint II. A small number of M13s were also built by Lexmark. The industrial M13 was first built by MaxiSwitch then by Unicomp under contract for IBM.

Orderable Part Number (OPN) 82G3282 is documented in 1994 specifically as a spares unit for OPN/FRU 82G3281 (Lexmark M13, beige.) However, there also appears to be an OPN/FRU 82G3282 which is distinct from FRU 82G3281. These keyboards are identical with the only difference being the point of manufacture - Lexmark at Plt.No F1 and MaxiSwitch at Plt.No 00. FRU 82G3282 appears to have been manufactured from 1996 to 1998. If you have any further details or examples of 82G3282's, contributions to This Thread would be appreciated!

Understanding the differences between the 82G3281 and 92G7461

The 82G3281 and 92G7461 keyboards are cosmetically identical, but completely different electrically. The 82G3281 was equipped with the original TrackPoint technology, first introduced in 1992. The 92G7461 is equipped with the TrackPoint II, an improved version which was first introduced in 1996. The two versions of the TrackPoint are not electrically compatible.

Keycap Information

The Model M13 is unique in that all models without exception use exclusively the "one-piece" keycaps for all keys. G, H and B keys have a unique shape to accommodate the TrackPoint stick. Other than these three keys, all other key caps are compatible with all other Model F and M keyboards. All M13s were equipped with PBT keycaps including industrial and Stealth Black (white-on-black.) Some M13s have a modified space bar stabilizer clip arrangement on the barrel plate to accommodate the button area.

Chassis Information

The M13 chassis is constructed entirely out of ABS plastic, either uncolored (beige) or painted (black, industrial). The M13 lower and upper sections are unique to the M13 and it is not possible to modify them to fit any other model or vice versa. The modifications to the M13 chassis makes it extremely weak on the front edge directly below and to the side of the button cut out; this area is not reinforced and breaks easily. It also makes the upper chassis prone to flexing on the front edge. Extreme care must be taken when handling the M13's upper chassis section, and it should never be stored disassembled. The M13's lower chassis is more robust than the standard Model M chassis, due to the addition of extrusions for anchoring the button assembly. The button assembly snaps in with un-equal locks. Care must be used when removing and installing the button assembly to prevent damage to the button matrix and latching tabs.

Care And Feeding

It is generally recommended to avoid disassembling the M13 if it can be avoided, simply because of the risk of damaging parts which cannot be replaced. Instead, the keycaps should be removed and cleaned and the keyboard should be turned upside down and shaken out. Do not ever use sharp objects or any abrasives to clean the top of the barrel plate! The TrackPoint ribbon cable runs on the top of the barrel plate and is fully exposed! If canned air is desired, never blow directly under the ribbon cable connecting the TrackPoint.

If dis-assembly is necessary, it is important to store the upper chassis upside down so that it does not rest on the button cutout area; this area is extremely weak and prone to breaking. All ribbon cables for the TrackPoint components are anchored using standard scotch tape; it is recommended to separate the tape from the chassis and to secure it to the cable rather than removing it. Attempts to remove the tape are likely to damage the cable. The button covers are clipped on to the lower button assembly. Do not attempt to remove the button covers without removing the top half of the chassis first. The clips on the button covers themselves are very fragile and easy to break.

Service Parts Availability

  • Uses standard Model M keycaps; G/H/B with cutouts available new from Unicomp.
  • Button Matrix Assembly is available new from Unicomp but requires minor modification to fit.
  • Barrel Plate assembly (including TrackPoint) is irreplaceable!
  • Button covers are irreplaceable! Use extreme care when removing and reinstalling!
  • Chassis is irreplaceable! Use extreme care when handling the chassis!
  • Controller is irreplaceable! Use extreme care when handling the controller!