2003 corolla factory stereo no sound

2003 corolla

stereo turns on lights up and you can adjust everything. NO SOUND . every now an then a bump causes a pop sound from the speakers but never music.

should I source another unit from the junkyard? any thing Im missing here.

Thanks

If there is a factory amp in the car that may be the culprit.  If not it could very well be a defective head unit. The only way to know for sure is to bench test it. Also check the wires at the dash..use a DMM make sure it has solid 12+ on acc. and constant..good ground. also check if any speakers are shorting..that can cause the symptons you are having as well.

Anything else is just a guess...you need to probe around before you assume it's the deck.

it could also be a blown speaker, or shorted out speaker wire causing the problem.  you might want to disonnect the speakers one by one and see if the problem goes away.

most likely though is that its a bad stereo.