I have a vintage PSW12 subwoofer which has been giving me problems recently.

It has stopped packing the "punch" in its sound output.

For last few months this problem came up and when I play something on my surround sound, it starts off ok but after half hour or so the "power punch" of the sub-woofer goes away. Although I could feel the speaker cone vibrate slowly but not to the level of its true performance.

Can somebody help / advise in this matter. Can I replace a component in the circuit board ??

Thanks

Saleem Ahmed
Polk Audio 5.1 Surround speakers
Yamaha RX V465 System