Squareback vs round back alternator?

Christian.
I suggest looking through this thread first.
Identifying Chrysler Alternators (1960-1976)
From appearences your regulator and alternator match.

It will be easier for you to diagnose once you understand the functional differences.
In the UK and US the circuit arrangements are called different things. In Belrlin maybe something else?
Basically the difference is whether the field strength is controlled by switching the positive feed, or by the negative connection.

Now (2022) you can exchange that mechanical regulator for a positive controlling transistorized version. However I do not know if that will resolve the problem.

Here's one sold by FBO through E-bay. I've been using it, but not long enough to say whether it is any more durable than others.
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