computer speakers humming ...

[jimjones]

because they don't know the words? :lol:

Ok, i have some old pc speakers who generate a low humming sound, not affected by volume settings.

After googling some i noticed that the sound remained, even if they were only connected to the power plug (which would eliminate a ground loop if i'm right).

The model is a ys 300 and the transfo (hope this is good english) is inside the right speaker along with a small pcb with some caps and stuff.

My question is pretty simple : what would produce the noise - is it the transfo or some fault on the pcb?

Oh, i also moved the pcb as far from the transfo as possible without noticing a change in volume or pitch.

These are OLD speakers, so it is probably an age problem. :wink:

 

[Joel Rainville]

because they don't know the words? :lol:

:lol:

Have you tried moving them away from your computer monitor?

 

[jimjones]

Have you tried moving them away from your computer monitor?

Yes, just connected to a power outlet and far away from the computer. Also no other possible interference sources nearby - and not just for 10 minutes after being turned on either - they keep hummin' all day :wink:

 

[audioguru]

If the speakers hum with nothing connected to the input then the power supply's main filter capacitor has failed.

 

[jimjones]

Ok, that would be the biggest tube on the pcb i guess - it is marked 25V 2200 microfarad.

Anyway i can test a capacitator with a simple multimeter? I would like to test the others too in case i decide to try soldering again for the first time in more then 20 yrs

 

[zachtheterrible]

One test you can try is to measure the resistance of teh capacitor. It should be infinite.

 

[audioguru]

If the electrolytic capacitor is dead because it leaked or has dried out then its resistance will be also infinite. Just replace the old thing.

 

[mstechca]

Look at the price of the capacitor, and then look at the price of the device. If you can fix circuits, go with the cheaper. Just make sure the capacitor replacement has the same or higher ratings.

 

[audioguru]

MStechca,
The 2200uF/25V capacitor costs only $.86CAN today at Digikey for one. Ten of them cost much less for each. :roll: