The correct way to repair it depends on whether it is all tube, hybrid (tubes in the RF sections and transistors in the audio sections), or all solid state.
In 1960 Chrysler first came out with an all-transistor radio. Before that they were all tubes. However, this was in the days of old-fashioned germanium transistors (modern ones are silicon), which didn't have the amplification factor that tubes had. Customers complained about lack of sensitivity, so in 1961 Chrysler went to a hybrid design in order to achieve a hotter front end. This hybrid type lasted for a few years, until transistors improved. I forget when Ma Mopar went back to all-transistor radios; probably in the mid to late '60s.
The correct way to troubleshoot it is: if it has tubes, check them. If it has a vibrator (all-tube or hybrid), check that. If it passes those tests, hook up a signal generator with internal modulation to the antenna input at about 1 mhz (10 on the dial), tune it in and use an oscilloscope to follow the signal to each successive stage of the radio. Be aware of the approximate amplification factor of each stage (will be either roughly 10 or roughly 100, order of magnitude; look up the specs for that stage's device) and check to make sure the signal at the output of each stage corresponds to that amplification factor (i.e., that it was amplified approximately the correct amount), and remember that after the IF stage you are looking for the frequency difference signal, not the 1 mhz. signal. Find the stage where you lose the signal or have much less amplification than you should have, based on that stage's theoretical amplification factor.
