I’ve been having a similar issue where a couple of ME-1 keys periodically become unassigned and display the “Key Unassigned” message, and I want to share what the issue was for me in case it can help someone else.
Background: If you create a stereo pair of processing channels in the mixer, and you want to patch that stereo pair to the ME-1 network, then you need to set up the mixer patching to the ME-1 network in the I/O tab so that those two inputs are patched as a stereo pair. Otherwise, the ME-1s will only receive one half of the stereo pair. You do this by tapping on the channel numbers on the X axis (horizontal axis) in the I/O screen on the mixer (at least this is how it works with an SQ or Avantis). A pop-up window appears allowing you to patch two inputs as a stereo pair.
Okay, so, once you’ve made a stereo pair available on the ME-1 network, then you can assign that pair to a single key on an ME-1 mixer. Everything is good until you recall a scene in the mixer where the stereo pair is not patched as a stereo pair on the mixer’s I/O screen. If the ME-1 has a key that is assigned to a stereo pair, but the mixer is no longer providing that stereo pair to the ME-1 network, then the ME-1 key will become unassigned, and it won’t reassign itself even after the stereo pair is available again.
A firmware update to the mixer is one time where the mixer will load a scene that does not include any stereo patching on the I/O tab for the ME-1. Additionally, if you have any scenes in your mixer that don’t include your stereo patching to the ME-1s, loading any of those scenes will cause the stereo pairs to become unassigned on the ME-1s even after you’ve returned to a scene with the correct patching of stereo pairs to the ME-1s.
