Rich --

I mentioned earlier that the other relay is for the electric fan, and is identical to the suppression relay. They can be interchanged in a pinch.

To resolder the original relay, other Bricksters have said you can cut the RTV compound sealing the black plastic box onto the relay and pop the cover off -- inside you'll find a small printed circuit board with the actual relay mounted/soldered to it. Often resoldering corrects an intermittent relay (true for all the Bosch relays, such as fuel pump, OD, and others).

However, you replaced it with a new one to no avail. Are you sure you replaced the right one?

Try exchanging the two relays, A for B.

As I said in my post a week ago, AM interference is cause by arcing. You said the AM noise "beats" in rhythm with the flickering lights, so is likely to come from the same source.

Someone asked if the replacement alternator was new or used. I asked if the ground from alternator to block, block to chassis, battery to chassis, and battery to block were OK.

You should probably also check the fuses to be sure they're firmly seated.

It certainly sounds like low alternator voltage, and the arcing may come from the brushes. I'd bet a cold one there's a connection there.