Re: gEDA-user: buzzing board

[andrewm <andrewm@xxxxxxxxxxxxxxx>]

<TOP POST - bad andrew>

Have you tried the contact microphone (pizeo buzzer)
yet to narrow down the location ?  Hook it up to your
sound card if you don't have a great scope.

I am assuming it is in the bottom right hand corner of
the picture where it looks like the switcher and the
SM inductors are that it seems to be coming from.

Maybe you could consider one more culprit in that
corner you may have over looked - the DC plug.




DJ Delorie wrote:
>> Ceramic caps on a switching power supply can have a pizeo eletric  
>> effect.  Try poscaps or a tant.
>>     
>
> The switcher caps are tantalum.  There are also two electrolytic bulk
> caps, one on each side of the switcher.
>
> Probably the best view of these is here:
> http://www.delorie.com/electronics/alarmclock/20070908-board.html
>
> The OLED's LDO is in the far upper right in that photo.
>
> For the purposes of solving this problem, I put the design files here:
> http://www.delorie.com/electronics/alarmclock/20070913-design.zip
>
>   
>> Did you cheap out on the inductor?
>>     
>
> Not that I'm aware of.  I used these:
>
> 495-2003-1-ND   EPCOS B82464A4104K (100uH)
> PCD2089CT-ND    Panasonic ELL-5PM3R0N (3uH)
>
>
> _______________________________________________
> geda-user mailing list
> geda-user@xxxxxxxxxxxxxx
> http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
>
>
>   



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