Anyone rewire a real DC-9 Annunciator (Analog Style)?

Hello guys. I want to have the ability to light up all the annunciator lights on my real DC-9 overhead annunciator panel for a display I am making. The original bulbs are 28v and initially I was going to try and use a 24v power supply I got out of a copy machine and see what all I could get lit up. I had tried using some of the existing barrel connector pins and was hoping it was just a matter of applying voltage to a pin used for testing the lights, but that didnt' seem to work. Then I started thinking maybe I should completely rewire this to use LED lights instead.

Has anyone done this specifically for a real annunciator? I'm not that experienced electrically, so I was hoping someone had some pointers on what type of LEDs I should buy and basically any recommendations of electronic parts I should buy to make this happen.