Pedalboard "ching" sound

[earltrane]

I keep getting a "ching" sound from my board and can't isolate it to a specific pedal or cable. I've disassembled and reassembled it - testing each pedal independently. And independently, I can't reproduce this "ching."

 

The sound I'm getting kind of sounds like a chain hitting another chain. It happens when I turn on specific pedals (Big Muff Pi, Robotalk), but like I said...when tested independently, they work fine. I'm also getting this sound sometimes when I'm playing louder or sometimes when my delays repeat (loudly).

 

Any help would be helpful. Thanks.