The Fadal 1090 keyboard controller uses an unkeyed and under sized header. So connecting the ribbon cable from the keyboard to this header allows several incorrect connections.
If after installing the keyboard replacement ELE-1784 the keyboard appears to not work. Most likely this is due to the connector not matching correctly to the 1090 controller. Most of the keys won't work, but there will be a few keys that do work but give the wrong output...
Here is a table of key press and the wrong displayed character on the screen. Press the key show and if it displays the wrong character on the screen then the reason for that is shown in the third column below. Correct the ribbons connection between the 1090 and the keyboard to fix the problem:
Press ----> Character Reason
N H Connector off 2 pins (too high)
N 7 Connector off 2 pins (too low)
N 1 Connector upside down
D I Connector upside down and off 2 pins (too high)
7 1 Connector upside down and off 2 pins (too low)