Repairing Otamatone battery compartment

I bought this Otamatone but wasn't able to get any sound out of it. I found the fault was a poor connection in the battery compartment, and fixed it by installing some solder braid to bolster the battery contacts. I've seen a few threads online from people who've had similar issues so thought I'd put a little video together. Apologies for my terrible playing at the end, I'm very new to this and haven't quite figured out the "fret" spacing! 0:00 Introduction 1:08 Battery compartment design 2:04 Repair procedure 3:56 Testing 4:16 Wonky scales