fixing am radio?
I know very little about electronics but was able to fix all the gauges in my 2005 GMC, my samsung Galaxy S3, and my xbox 360 because of the huge amount of videos on youtube on those subjects. Unfortunately guys who know how to fix old AM car radios must not know how to make and post videos to youtube.
Personally, I would use something like this
[ame="http://www.amazon.com/Pyle-PLMPA35-Channel-Amplifier-3-5mm/dp/B004HJ931M#productDetails"]Amazon.com: Pyle PLMPA35 2 Channel 300 Watt Mini Amplifier with 3.5mm Input: Car Electronics[/ame]
Hide that away, get a couple 6x9s in wooden boxes, run a 3.5mm male to male cord to your cell phone, and get I Hart Radio and Pandora. Songs, radio, sounds good, doesn't change any factory part of your car.