alternator or strobe whine

I have 1000 hrs and have just started hearing a high pitched whine in the headset. I don't get it on the ground but once airborne it becomes quite noticeable. If I turn the strobes off, the noise goes away. If I leave the strobes on and turn off the alternator the noise also goes away. The alternator is a Plane Power 60 amp internally regulated. The strobes are the generic whelan discharge type.


Also, I have always had a bit of noise coming from the led landing and taxi lights. Not as loud but still noise. Again, if I turn the lights out the noise goes away. If I leave the lights on and turn the alternator off, the noise goes away.
These led lights are home brews so not surprising that they are noisy, but this noise also seems to be getting worse.

I did replace the battery with a new PC 680 and no change in noise.

Now, I'm thinking a bad diode??? Are they replaceable, or will it have to go back to the Plane Power people?

Thanks,

EZ fix

You need a new diode board. PP can sell you one, and you can install it, or you could send it in for repair, or you can go to a local alt repair shop. Piece o cake!

Carry on!
Mark

i put a cheap noise suppressor on my alternator for what it is worth. $20 or so.

1000 hrs? It is a good time to check bearings and brushes in that alternator anyway. If it suddenly occurred and no other changes, then likely the diode, as you have surmised.