In the process of retro-fitting my #Flight2000 with the LED lamp adapter kit, I have lost 2 of my insert lamps. I replaced the lamp sockets and the bulbs but they are still out, telling me the issue is probably closer to the lamp board. I have a multimeter but I don't know where to start to troubleshoot this.

Also of note: when removing the LED adapter kit and re-adding it again, I noticed both lamps came back on along the way at some point, but now they're off again. What should I test to see where the fault is?

That was it - just a loose connection. I really wiggled a lot of the connections till it finally came on. Might have actually been a wire too, thanks guys!