TSGL: 60 Hz Hum from Laptop?

[H Davis]

Geoff,

If none of the other suggestions work try connecting a good ground from 
the case of your laptop to a ground on your amplifier (there's sometimes 
a screw on the back of the amp for just this purpose). It's possible the 
case of your laptop is isolated from the electrical circuits on your 
motherboard and power supply. In that case you'll have to get further 
inside to find the ground side of the circuit.

If you have an ohm meter, measure the resistance between each power 
supply terminal on the laptop to the case to see if one of them is 
connected directly (0 ohms) to the case. Disconnect the power supply and 
remove the battery before measuring.

It's possible that your power supply is bad. Try substituting a 
replacement unit for a test if you can.

H Davis

Geoff Glave wrote:
> Hey All,
>
> As part of our entertainment system we've got an old Dell laptop plugged into our amplifier.  It's on our wireless home network and we use it to play MP3s and listen to 'internet radio.'
>
> However, it's got an annoying problem.  When the power supply is plugged into the laptop (i.e. most of the time) you hear an annoying 60-hertz 'hum' over both right and left amplified channels.  If you unplug the power supply from the back of the laptop, the hum goes away.  I've tried running a ground to some of the external metal on the laptop, but instead of the hum getting better (as expected) it got worse.
>
> Any suggestions as to how to make our home entertainment system work better?  How can we get rid of this 60 hertz hum?
>
> Thanks in advance.
>
> Cheers,
> Geoff in Vancouver, Canada
>
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-- 
H Davis   hdavis1 at gmail.com