> Get an electret mic running off a battery on one scope lead Circuit? I tried the mic+scope trick, but nothing came out of it, so I figured it needed some biasing.
> Probe around with other scope lead to see what is in sync with it > just to make sure you are looking at the right part of the circuit. I can "see" the oled's image in the +12v noise, kinda like looking at a video signal through a low-pass filter, but you're right - I might not be hearing *that* signal. > You could spend ages looking at that switcher for the OLED and find > out that the buzz was a slightly different frequency coming from > somewehere else. The OLED uses an LDO linear regulator. The switcher is for the +3.3v rail. If I pull the jumper off for the +12v to the OLED (independent circuit), or just cover the photocell so it goes to "dark mode" (almost no pixels on), the buzzing stops. _______________________________________________ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user