Bose AWR1-1W Wave Radio - High Pitched Squeal in right channel

[redpackman]

The squeal is not affected by turning the volume up or down. I can hear the radio station playing but the high pitched squeal is very loud and makes it impossible to listen to it. The squeal is always there as long as the radio is on whether in AM, FM or Aux, high program volume or low volume...always the same squeal level. When the radio is turned off the squeal stops. The Squeal is only in the right channel and the sound "behind" it of the radio broadcast sounds quite distorted compared to the left channel. I think the squeal is around 2400 hz.

I've taken the radio apart enough to get at the circuit board. I cannot see any obviously burned/problem parts. I'm assuming this must be in the right portion of the amplifier section or the right pre-amp section of the unit (if it even has a "pre-amp" section") since the left channel is not affected.

Any ideas?? Any schematic of the AWRW-1W and help pointing out where the right channel section of that schematic would be?

 

[jhjove]

I've repaired 3 of these wave radios.

Two of the AWR1-1W models and one AWRCC1 (slot loading CD).
A squeal symptom was not with any of these 3. I had a loud buzz in the original 2 models and a "Please Wait" message on the CD version.

In all cases the crappy e-caps were the causes.

The AWR1-1W power supply caps and the supporting caps near the TDA7374 power amp chip fail. And I had visual electrolyte leakage to no visible signs of failure on bad caps.

Also the dimming display function was affected by bad caps.

In all cases I cleaned and reapplied silicon thermal paste for the TDA modules.

NOTE: The AWRCC1 uses SMD style e-caps, these had failures as well.

Schematics, they can be found. This site may help but I really did not need a schematic.
It will be important to have the correct serial-number of your AWR1-1W ....there are differences among (I think there are at least 3) these "original" BWRs.

Good luck.

--Joe