Re: gEDA-user: buzzing board

[DJ Delorie <dj@xxxxxxxxxxx>]

>    Is it convenient to try putting an choke in series with the OLED's  
> power supply line, with the OLED's bypass capacitor on the OLED side  
> of the choke?

Hmmm...  100uH power inductor, no change.

>    I've only used those two methods, aside from probing around with
> an oscilloscope to look for the noise.  One other trick that I've
> not tried (if anyone can comment on this I'd appreciate it) is to
> use an inductive pickup probe to look at the *current* waveforms on
> the supply lines to different parts of the circuit, and see what
> corresponds to the noise you're hearing.

I don't think my parallel-port scope is sensitive enough for that.
Plus, anything with a coil just picks up magnetics from the switcher's
inductor, but the switcher isn't the supply that provides the +12v.

> > 2. What kind of components *can* make that kind of noise?
> 
>    Inductors and PCB traces, mainly...but I suppose nearly anything
> probably could, to one degree or another.

PCB traces?

> > 3. If you know what's causing it, how do I fix it?
> 
>    Hot glue, molten wax, conformal coating..

I've tried pressing on various parts of the board to no avail.


_______________________________________________
geda-user mailing list
geda-user@xxxxxxxxxxxxxx
http://www.seul.org/cgi-bin/mailman/listinfo/geda-user