I've noticed some unusual noise in my Becker radio that I think is coming from the electrical system. It occurs when listening to an FM station as a sort of burping sound when at idle. An increased electrical load such as headlamps or a turn signal cause the sound to increase. Increasing the engine RPM causes the sound to stop. When listening to AM radio at idle, the sound is like a growl that rapidly turns into a screech as the engine is accelerated. Since this is a diesel engine, it can't be from an ignition circuit. I suspect something in the electrical supply system, perhaps the alternator or voltage regulator.
What are the possible/probable causes and what should I do?
Thanks,
Peter Hollings