New test results:
I checked the pcb of the keybed. It seems that the pcb is prepared not to be used with the foil-cables only. Next to the foil-connector there are smd pads. I think, that I could add a standard micromatch-connector to the board. This made it easy to see, which pins are connected to something. Because I don’t have a micromatch-connector here, I added a standard 20pin ribbon cable.
I realized, that there are a lot of pins left open. As you can see in the pic the top row (which should normally contain the row-signals) has no traces except for the last two pins (pin 1 is most right).
I removed the rubber contacts to see where the traces are going to. The lower row of the connector leads to the makes and brakes, the top row to the diodes.
I connected pin 1 and 3 of the right side (MK5 and BK5) directly to the DIO to O5 and O4 of J4. Result: I can get the first eight keys of the right half working with the correct note-output: C#3 - G#3.
But now I don’t know where to connect the other pins. I tried to connect MK6 and BK6 to MK0 and BK0. This leads to the problem mentioned above: The triggered notes are starting at a-1. So:
C#3, D3, D#3, E3, F3, F#3, G3, G#3, a-1, b-1, etc.
Connecting MK6 and BK6 to O3 and O2 of J4 don’t have any effect. And again: Adjusting din_key_offset has also not effect.
The fact, that I can trigger C#3-G#3 without connecting any rows of the right half leads to the assumption, that there this will might not function correctly without adjusting the firmware.
Any tipps how to proceed?
Thanks!
Chris