So I thought I was having a brain drain. The tap tempo / tuner button is going slightly off kilter. The tap tempo works fine. But the tuner will not activate. I did a complete dusting out of the guts and prior to realizing what I was seeing I replaced the tap tempo / tuner footswitch/spring/plunger assembly (yes I has a few new parts from previous spare parts purchase for my other M13 I traded for a Helix). Then it struck me, hmm ... the tap tempo is working so maybe not the button - Duh! Well then I accidentally switch off one of my time based echos and the darn tuner works, Hmm, try it again and same thing ... tuner works. Switch to another scene ... no tuner love. Move expression pedals up and down and I get tuner love back but after a second attempt to get the tuner to respond I have to turn off my echos FX on that scene again. So, anyone else have this happen and found the real solution? Any feedback would be greatly appreciated. Thanks, Dennis