Interesting Lexmark Model M

[Half-Saint]

Recently I picked up an interesting Lexmark Model M from 1994. No Lexmark label on top cover, just an empty square. Made in USA yet the layout is ISO, one-piece key caps. It also has drainage channels and holes. What's interesting to me is that the case has a hole for the SDL connector but the controller PCB doesn't feature one. The PS/2 cable is connected to a very small 4-pin connector.

Interestingly, LEDs do not light up although Caps Lock, Num Lock and Scroll Lock register fine. Used a Blue Cube to connect it to my laptop.

[webwit]

Maybe it's a construction of two Model Ms? The case is older than the insides?

[daedalus]

Before the 42H1292 style Model Ms, fixed cable Model Ms had the same case as the SDL cable keyboards, there was just a piece of plastic on the cable that covered the hole. If yours is missing that piece, then maybe the original cable was damaged and replaced by a third party.

Which ISO layout was it? It wouldn't be uncommon to see Canadian French and Latin American Spanish keyboards that were made in the US.

[cactux]

[Account and posts deleted on request]

[Half-Saint]

Before the 42H1292 style Model Ms, fixed cable Model Ms had the same case as the SDL cable keyboards, there was just a piece of plastic on the cable that covered the hole. If yours is missing that piece, then maybe the original cable was damaged and replaced by a third party.

Which ISO layout was it? It wouldn't be uncommon to see Canadian French and Latin American Spanish keyboards that were made in the US.

Indeed, the keyboard has the small piece of plastic covering the hole.

Mine is Yugoslav ISO layout which is funny because all the other YU ISO boards I have were Made in UK.

[Half-Saint]

Any idea why the LEDs don't work?

[Half-Saint]

Bump.

[acfrazier]

Any idea why the LEDs don't work?

Could be many reasons, but it's difficult to tell without opening it.

In order of likelihood:
Severed/missing connection internally
There aren't any LEDs inside
Burned out LEDs (as in, they had been turned on for more than 50000 hours or about 5.7 years)

[Half-Saint]

Well, connections appear to be intact, LEDs are there. Haven't tested the LEDs individually but I doubt that all three would burn out.

[Half-Saint]

Still no idea to why the LEDs don't work. The board otherwise works fine.