Have a BU2 subwoofer no sound

Yeah, it sounds like it's over heating. Are you driving it way loud?

WE REPAIR THESE AMPS - EDWARDS ELECTRONICS - EBAY - :)

I suspect that whatever semiconductor does all the amplifaction has departed this life. If you check the PC board it might point to a burnt out part or a blown one. If not look at anything big or with a heatsink on it.

apparently there is are some components on the main board that need replacing:

This is usually what needs to be replaced on these subs.

Replace

R830
R831-4.7 ohm 5% 1/4w fusible
C860 - 082 mf 5% 50v

Direct from Sony:
hxxp://servicesales.sel.sony.com/ecom/accessories/web/index.jsp

c860 is Part # 113616400 $2.14
r830 is Part # 121284900 $2.14

this may be a dumb question but have you turned up the signal. there should be a dial on the back that you can turn the power up. power light on, signal passing threw, the only other thing it can be is the built in amp itself may be dead.

Please intimate exact model number written on sticker pasted at back of Sony subwoofer to provide you help.

There could be a fuse gone in the plug or in the power supply itself. Try a universal power supply to see does that solve the problem.

Just plug it in to an outlet. The lights on the front should be red (or standby mode). When it gets a good sound signal, it turns green (that's when it's on). It does not have a power switch.

I have the same speaker and it sounds like its behaving properly.

if you look on the back of the amp, you will find a switch that allows the speaker to automatically switch the speaker on or off based on the level of the audio coming from the tuner that it is attached to. If the switch is set to the auto mode, then it will listen for audio on the line and if the signal level coming into the subwoofer is high enough, the amplifier in the subwoofer will turn on and play. If the signal is not strong or loud enough, then the subwoofer will not turn on. There are two solutions to getting the speaker to work.

1. When you turn on the tuner or audio source that is feeding the Subwoofer speaker, you will need to turn it up loud enough to trigger the circuit in the subwoofer to switch on.

2. Alternatively, you can bypass the automatic circuit and set it to the "ON position all the time. In this position the subwoofer is always ready and waiting and should play any signal that is fed to it regardless of the loudness or volume of sound from the tuner. The switch is located on the back of the speaker cabinet just to the right of the red and black speaker wire connections. It is labeled "AUTO" and the switch positions are labeled ON and OFF.

Hope this helps!