MPC 1000 'FULL LEVEL' LED not working after installing

My MPC 1000 had two LEDs that were out, 'FULL LEVEL' and '16 LEVELS'. I installed a new LED for both. '16 LEVELS' works fine. 'FULL LEVEL' still does not work.

The functions themselves work fine so it's not the end of the world, but I'd still like to get it fixed.

What could be the issue? Broken trace?

it's super easy to install LEDs backwards, and they won't work. Just wanted to make sure that you know you put the LED in the right way. Depending on the LED, you might be able to test it with some voltage from a battery to check polarity.