Trying to save a sangean hdr-1 that has a 60 cycle buzz, no audio, no am or fm stations. all functions on the lcd work, volume controls the buzz loudness. also mute works. clock sets fine. filter caps and rectifiers ok. no cold solder connections noted. out of the case with power on, no components getting hot. using headset jack everything is the same. using scan on the tuner it will scan but not stop on a station. manually on a known station no audio detected only buzzing sounds like 60 cycle square wave. Anyone have any ideas?