Protect push power

First things first. The unit doesn't switch on.
- Is it plugged in?
- Is the fuse blown?
- Does it look like it's suffered damage?

It switches on, but won't play anything / the lights come on, but no sound.

- We'll start at connections. Is your MP3 player/ iPod/ CD player/ record deck plugged in correctly?
- Are the speakers plugged in correctly/ at all?
- Is it in protection mode - this is a pretty standard thing now, where the amplifier tries to deliver more than it's rated current (ie, into a short circuit), and it cuts out. The only way to fix this is to take it to a local hifi shop, who will reset it (there's usually a small fee involved). The unit will be fine after that.

------- There is no bass. ----------
A few causes for this, so there's a few solutions.
- The speakers are out of phase. This is where one speaker is wired normally, one is wired in reverse. The bass from each speaker is "opposite" and would cancel out. To solve this, Make sure the + on the speaker is connected to the + on the amplifier. There's usually a stripe on the cable to help you determine this.
Cause # 2
The eq settings on your ipod/ unit have been messed with.
Set all the equiliser settings to flat, then readjust them to taste.
Cause # 3 (nasty one)
You've blown a woofer. The explanation is this - the speakers have taken in too much power, the bass unit has got too hot and the glue holding the coil in place has melted. Usually, the woofer can't be physically pushed when this happens. To solve this, it's new speaker time. An alternative is to see if you can get a recone kit for said speaker, and try to fix the voicecoil yourself. This isn't recommended to those who are new to the idea.

I hope this helps the reader.
Chris