LEDs - 3 generations, 3 different issues.

[Wh1terat]

I've got 3x Model Ms I've fitted with the Model-H board.
All working nicely as a keyboard but all have different issues relating to the Num/Caps/Scroll lock LEDs.

Any suggestions?

1988 "Silver Square"

This previously had the BLUSB controller from mind_prepared but unfortunately the LIPO did what LIPOs like to do and expanded. It has the replacement "lower power" LED strip from blusb.

Num Lock: No LED
Caps Lock: Turns on Num Lock LED
Scroll Lock: No LED

1986 "Silver Square" (Very early - with "foam wedge").

Num Lock: No LED
Caps Lock: No LED
Scroll Lock: No LED

1990 "Grey Oval"

(Sorry no pic of LED strip - but uses FPC rather than JST connector, like example in readme)

Num Lock: No LED
Caps Lock: Works
Scroll Lock: No LED

[jberclaz]

Good to hear that you were able to use the Model H in three different generations of Model M. For your issues with the LEDs, I would suggest the following:

1. check the cable with a multimeter. I had one keyboard where the ribbon cable to the LEDs was broken (even though there was no obvious visible damage).
2. with a multimeter again, check the current at the LED connectors on the board. You should get current into a different one of the 3 outputs for each LED (num, caps and scroll). If you don't have that, I assume the board is broken.
3. you can switch the lights in the firmware. For that you'll have to recompile QMK. Open the file keyboards/ibm/model_m/modelh/keyboard.json and switch the values found in the indicators block. You'll find instructions on how to compile the firmware on the repo.
   Hope this helps.

[Wh1terat]

Ok so keyboard 1 and 2 are the same problem. The PCB has the wrong pinout 🤦‍♂️
Re-pinned the JST cables to get it working:

Keyboard 3 was just a dirty FPC connector 🙈

I really don't like the way the FPC cable has to twist, if the board were ever to be revised it would be nicer to use a full size board footprint like original PCB and move the LED FPC socket to the top and orientated properly AND leave a footprint on the right for the JST connector for these earlier boards (with correct pinout).

[jberclaz]

Glad to hear you made it work.

I agree that the position of the LED connector is not great. Though, I believe the design is intended to match the shape and size of some of the later boards, which were smaller.

[Wh1terat]

I do wonder which generation board that top one is, certainly a less common one I would say.
Especially when looking at photos on: https://sharktastica.co.uk/wiki?id=modelmenhanced

I recently came across another project focussing more on wireless keyboard (and thus ZMK based) which looks to incorporate a number of improvements:

https://github.com/NilsFC/Model-X

[SharktasticA]

I do wonder which generation board that top one is, certainly a less common one I would say. Especially when looking at photos on: https://sharktastica.co.uk/wiki?id=modelmenhanced

I've seen keyboards with that controller card (typically P/N 1395601) made between 1990 and 1991 which would be within the "second gen" (this card style is currently absent from my website because I don't have any good, usable photos yet). Here's a dated example from the Ardent Tool:

[Wh1terat]

Thanks @SharktasticA
Still amazes me how many revisions of the controller exist. Talk about reinventing the wheel 😄

If you'd like any higher-res photos of the boards/plates/etc I have (the black/purple PCB perhaps) do let me know.

[jberclaz]

Still amazes me how many revisions of the controller exist.

True, out of the 6 Ms I have, none of them has the same controller.