My jvc kd-g820 will not produce any sound and not accept cd

Try to find the reset a little indent on the face or hole when you remove the face and push in for 2 to 3 secs with a pen or paper clip. Then try your cd again. Still dont work check to see if you have another cd jammed inside and your trying to put two cds at once.

Ok for your no sound problem. a bad speaker, short speaker (one 1 speaker shorts out all will not work cause the radio is in a protective mode), factory amp needs to be turned on, bose system or amplified system in car needs to be rewired to bypass factory amp), buy special car harness to make factory amp compatible with aftermarket radio, late ford models the back speakers are crisscrossed.

Next time please give car info and type of system you got in it so I could narrow down the possible problems a little bit easier.