@herman wrote:Hi Anrea,The first thing to try would be exchanging the two amplifiers and see if the problem moves with the amplifier.Probably some goo...

No idea?

Ops! I didn't noticed the polarity was inverted...Thank you very much, now the speaker works perfectly. Just I can't screw the screw close to the elec...

Hi,Thank you for your reply and help. I bought a cap 330mf 25V. Now the speaker switches on, works perfectly for 10 seconds and then the sound fades ...