Re: Static

On 14 Jun 2003 at 11:25, Christoph Berg wrote:

> Re: [Linux-sony] Static [Andrew Grimberg <[email protected]>,
> Fri, Jun 13, 2003 at 04:01:14PM -0700,
> <[email protected]>] > For some time 
now
> whenever I'm on battery power any access to a moving > part or part
> that has any RF capabilities has generated a consistent low > level
> static over my on board sound.  This occurs even during the moving 
>
> boot logo.  Making me believe it's not sound module related.
> 
> I'd suspect that a capacitor that filtered the noise is broken now. 
It
> will probably be hard to locate it, but it could be a starting 
point.

For the adventursome....
If  Christoph's guess is correct it will probably not be hard to 
locate, as
the defective capacitor would be located near the power inputs from 
the battery.  This is usually indicated by a bulgeing capacitor, 
perhaps showing
signs of leakage when compared to similar capacitors (also called 
"Cans" because they look like little cans).

These are fairly small in a laptop, and replacement is going to be a
"go blind" because doing board level repairs is bad enough on a 
regular
machine and a nightmare on a laptop.

I suspect its not a capicitor but rather a step-up voltage chip.
Your wall power typically delivers 19 volts to the laptop, and the
battery delivers (usually) no more than 12 volts, and sometimes
only 5.  to get the higher voltages they use a chip which increases
the voltage (at the expense of using more amps).  (Since its all
DC, this requires more than a simple transformer.)

If you only hear it on battery power, it sounds more likely that
this is the case than a power filter capacitor on the power supply.

-- 
______________________________________
John Andersen
NORCOM / Juneau, Alaska
http://www.screenio.com/
(907) 790-3386

._______________________________________
John S. Andersen
NORCOM  mailto:[email protected]
Juneau, Alaska
http://www.screenio.com/