The rubber backlite two cable will probably not light up
I tried on a cf-72 and is did not,so I am thinking the same on the cf-73
If you can find a source of 5vdc,like usb power you can try a 3 cable and mod it
Its my plan on the cf-74
Do the 72, 73, and 74 take the same keyboard? Cuz I know a 72 keyboard (non-backlit) will fit perfectly into a 28.
The 28 will light up a 2-cable rubber backlit, same as a 27, but apparently the 72 will not. There were kits with the little Texas board for the 28 that fired up two different 3-cable backlit keyboards: the green high-voltage emissive and also a more rare circuit that fires up the 29 type chicklet emissive. I would bet either of those could be modded into a 73 if the keyboards will physically fit and the other 2 cables will fit.