Logitech z906 buzzing output

[hpibmx]

Hi,

I've got this Logitech Z906 with no sound at all, but when it's touched by my finger i can hear it's being detected and amplified!
after changing input first time I had sound for 2 or 3 second then it was gone. (which was not clear or loud though)

what I've done,
- new 3.5 audio jack with different devices,
- tried different inputs
- tried resting by holding input button for 7 sec
- tried 3 or all 5 speaker connected


thank you for advance.

[Rasz]

 I think we had a few threads about those with  blown power supplies