Sounds like you are on the correct track.  I bet the issue is a broken or nearly broken nose gear switch.  What did your amp meter show during the flight with the whine occuring?  If it was showing a discharge you can bet the hydro power pack was running the whole time and causing the electronics to fail from lack of power.  Do you have pullable cb?  It would have been helpful to pull it in the air to see what was going on.

Mark
N1161J
1974 112a Hot Shot (sn.161)
Based at Pontiac, MI (PTK)