Misc: Charging Systems Electrical Whine from generator when turned on pre start

[Speedtwin]

Here is a strange one.
Noticed on my D which is positive earth, 12v, electronic regulator rectifier, when I turn the ignition switch to on, a high pitched whine comes from the generator housing if I press the cover in and out I can play a little tune on it.

I was wondering why this is happening?
If anyone has any experience of this phenomena or advice?
Never noticed this before I am new to these modern 12v systems on the technologically advanced D series.

I had just fitted a new battery and cleaned up all the connections on the loom, earths all the usual switched her on and I had a potential xylophone under the seat...

I realise that when coils are excited they can vibrate or whine, should I be worried?
Or am I just paranoid?
I suppose I will not hear it when it is running and on the positive side can entertain onlookers with some tunes at petrol stops.
Any advice from you guys would be lovely.

Al

.

 

[roy the mechanic]

I had something similar a while ago. Turns out it was a bad connection between the A O services black box and the dynamo.

 

[Speedtwin]

Thanks Roy,
Will pull the cover of the dynamo and check it out the connections, all up at the box are grand
I think, was too lazy to go get my glasses from the house when cleaning the connectors under the seat.
Ah the joys of getting older and more apathetic.
Al