On Nov 26, 1:05*am, Frank-Stefan Müller wrote:
Hi,
my good (?) old Logitech X-220 PC speakers start to whistle very loud as
soon as I power them up.

Any idea or schematic?

Thanks

Frank

Unplug them from the computer and see if the problem is in the speaker
amplifier or the sound chip circuit. If in the speaker amp, turn the
volume control down and see if the whistle goes up and down. If not,
look into the power supply for the speaker amp. If it does vary, look
at the power supply as well as the caps in the amplifier circuit.

Neil S.