Hello !
I am building a B737 MCP. I designed the PCB, checked the displays and encoders worked with that design and built the thing... I was an idiot and did not check the LED outputs, as I thought... it is just an LED, I will connect it and that's it 
The problem (there is always a problem) is that I designed the board to connect the LEDs to the output multiplexers... instead of using an LED driver.
I've been thinking about it but I can't come up it a fix without having to re-do the whole thing... as obviously, when I try to connect an LED to the MUX, it warns me that (the mux) is not an LED driver !
Aaaaaaany ideas or suggestions before I scrap the whole thing?