Audible 9kHz noise

[wonkoderverstaendige]

Our acquisition board (v2.1, board 39) is emitting a very annoying high pitched tone once initiated from the GUI. It doesn't depend on the connected headstages, as far as I can tell, but slightly changes in frequency and amplitude when you start the acquisition, but won't stop afterwards unless you disconnect the power plug.

Waving the microphone over the board hasn't given me an exact source yet, but I could try to do so in a more systematic manner if needed.

[jsiegle]

I would check the boost converter (above LED 6, to the left of L2). We've heard high-pitched noises related to this in the past. First check whether it's overheating, then check to see whether the various test points (+5.5V, +5VA, -5VA) are the right values.

[jvoigts]

yea i'd say go around and check for hot spots with your finger. We've had that happen when we had shorts on the board before.