Ike gave you some great advice, so follow what he said and let us know what you find.
The "bzzzz" sound suggests an intermittent connection to me, which means a connection is oxidized, a terminal is loose, a bad solder joint, etc. The "bzzz" can actually be some electrical arcing (or micro arcing). Sometimes these arcs create a temporary "weld" between the two halves of the connection, but these bridges have more resistance than a regular clean connection and usually fail quickly due to heat build up and thermal cycling. Once they break apart, the process starts over again but the base metal is weakened so the "weld" doesn't last as long. Cheers, -- Don
