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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment.

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Old 22nd Mar 2023, 2:17 pm   #1
martinhog
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Default Bose AWRC-2P - Dead

Hi, it's 23 years old according to the date code, so vintage in some folk's eyes !

Can anyone advise ?, I have fixed a dead one before by changing Q4, however this one (also dead) has a different PCB. All the secondaries on the mains TX are OK, there's 16V DC across C8, but nothing on the inputs to the 5V and 10V regulators . This model is a wave radio/cd.

All advice gratefully received.
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Old 22nd Mar 2023, 3:44 pm   #2
Analogue man
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Default Re: Bose AWRC-2P - Dead

Quote:
Originally Posted by martinhog View Post
Hi, it's 23 years old according to the date code, so vintage in some folk's eyes !

Can anyone advise ?, I have fixed a dead one before by changing Q4, however this one (also dead) has a different PCB. All the secondaries on the mains TX are OK, there's 16V DC across C8, but nothing on the inputs to the 5V and 10V regulators . This model is a wave radio/cd.

All advice gratefully received.
Then the fault must lie between C8 and the regulators, is there a fuse there or perhaps a resistor or even a broken track on the PCB.
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Old 23rd Mar 2023, 10:48 am   #3
martinhog
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Default Re: Bose AWRC-2P - Dead

Good morning,

Many thanks for your comment. I have found a circuit diagramon line for a similar model (earlier) the 16V DC across C8 is only used for the audio IC. A seperate winding with half wave rectification feeds the regulators via some switching components, a third winding feeds the display.

it seem Q4 (that gave issues on the earlier versions has been designed out.

All comments appreciated, thankyou.
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Old 31st Mar 2023, 4:17 pm   #4
martinhog
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Default Re: Bose AWRC-2P - Dead

UPDATE: Some progress made with both 10 V and 5 V rails now present.

The Radio works on AM and FM as does the aux input. My only issues now are the display is not very bright and the volume cannot be increased, it's "stuck" on 50 . It counts up to 50 if I power of and then on again.

Any advice gratefully recieved. Thanks
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Old 1st Apr 2023, 11:09 am   #5
Edward Huggins
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Default Re: Bose AWRC-2P - Dead

You are lucky to have found a circuit of any piece of modern BOSE kit. Their Tech Support team gives nothing away!
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Old 3rd Apr 2023, 8:58 am   #6
martinhog
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Default Re: Bose AWRC-2P - Dead

Good Morning Edward,

I have to say I was surprised, Mr Google was very helpful on this occasion !

It's slowly coming back to life, I was keen not to tell the owner to chuck it away.

Regards

Martinhog
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