I have a Nano Big Muff Pi and a Nano Looper 360 that suddenly won’t work with battery power, but does work with wall wart. I had these two along with a Soul Food and a Pitchfork in a chain powered by a 1Spot. There was nothing unusual, but after I took everything apart and tried to use the Nano Big Muff it wouldn’t work with just battery power. It does with wall wart. I am now using the EHX one as that worried me about using the 1Spot.
Anyway, I checked the other three petals and the looper was the same as the Muff. The Soul Food and the Pitchfork do not have this problem. Of course I tried new batteries, several of them, and that isn’t the problem. I see no wires disconnected or anything else like that, but I am no electronic technician. It is interesting that both pedals would do this. Has anyone else encountered this, or know what the problem may be? Thanks for all and any help.