I bought a Zoom H2N handheld recorder from Goodwill, and I knew there was a risk…

I bought a Zoom H2N handheld recorder from Goodwill, and I knew there was a risk there but was still disappointed that it added a quiet but audible pitched noise (maybe around 1760 Hz?) to its recordings. You can hear it in the first bit of audio I attached.So, today, I took it to the basement and took it apart to see if there was anything obviously wrong with it. Nothing. I put it back together and tried it out. No 1760 Hz whine! Miraculous. Like turning a computer off and back on again to fix something. You can hear that in the last recording.When I brought it back upstairs, the whine was back. Dant-dant-dah!So, I went downstairs and tried it out and found there was no whine.I didn't fix anything, but there is something upstairs that gets picked up by the H2N. Good enough! I can live with not using it upstairs.