Often the coin-lockout mechanism on the coin door is a source of buzzing.
The coil on this mechanism is a constant duty coil that normally will get
warm. Its purpose is to return coins when the machine is not turned on. It
has little or no use for the machines in the home. You can clip the wire to
the coin-lockout coil and wrap the lead in electrical tape. I don't
recommend removing the mechanisms because someone in the future may desire
to use this feature.