Well, didn't find any charging system issues to account for the buzzing in the radio. Ripple voltage was 0.06VAC at the alternator B+ and at the batteries. Alt leakage test was 0. Couldn't get on the starter with the plastic cover on the connection so I didn't do a V drop. I did find resistance from driver side B- to engine block to be 0.6ohm and passenger side to be 0.4ohm. Though that was a little high. Cleaned up the grounds where the battery cables meet the block on both sides and no change. Maybe that's normal? Way less than 10a loss if I'm doing the math right.

 

Resistance tests across large cables won't tell you much. They handle hundreds of amperes. A voltage drop test across the connections during cranking will tell the tale.

 

sorry, wrong forum