Help with Car amp troubleshooting

[strmtrooper]

Ok first off I am a relative neewbie to car audio and don't claim to know much so please be gentle.

I was given a sony xplod xm-2002gtr by a friend so that I could have a little bass in my system. I connected the amp to a 4ohm mono speaker and ran it in the mono configuration on the amp. This setup worked for a few days, then the amp started cutting out. It seemed to happen when going over a bump. I checked the wires and even ran new amplifier wiring as the old wiring that came with my car was preety bad. I kept having the same issue and noticed that the protection light was lit some of the times that the amp wouldn't work. I tried connecting a different 4 ohm speak with no luck. Now the amp doesn't try to push the subs, even thought the power light is on and the protection light is not lit up.

I thought that the amp wasn't producing any sound but when I turn the speakers off and let the radio push just the amp and cranked the radio WAY up I get sound from the amp, which I can only assume is the non-amplified signal being sent to the amp.

In short I just need to know if my amp is fried or if there is something else that I should be checking.

 

[brandes.cm]

The only experience with sony amps happened the other day, all of the solder joints on the power supply fets/ transistors were fractured. When I applied heat to reflow the solder the lead would physically move.

It wouldn't hurt to pull the cover and look at the solder joints.

 

[Perry Babin]

With your meter set to AC volts and the radio at high volume (as when you heard sound from the amp), what voltage do you read on the speaker terminals. Check both channels.