Question about Sony HT-DDW740 System

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Sony HT-DDW740 Tuner Hum

I get a very noticeable hum when I select either the AM or FM input of this tuner. The CD input and other inputs sound clean, so I am wondering if there is any information about a power supply that feeds only the tuner module that could be causing this, ie a bad filter capacitor or voltage regulator. Any suggestions?

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  • Anonymous Dec 03, 2008

    I have the same problem with my Marantz 125. However, blowing the thing out with CO2 and then spraying electronic contact cleaner through the circuit boards has at least got the tuner itself working again -- prior to this all it was do was hum.

    It sounds like the B supply may be going. Perhaps that is what's happening to your tuner as well.

    Best regards,
    Jimmyblues

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Hi:
On the stanby power supply replace or have replaced C899 with a 100uf 35V capacitor, this capacitor goes bad and produces hum in the supply voltage to the AM FM circuits.

Posted on Dec 21, 2009

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quang123
  • 107 Answers

SOURCE: Tuner Hum on Sony HT-DDW740

Check electrolytic capacitor C899 100uF 35V in STBY PCB
Cheers

Posted on Dec 02, 2008

6ya6ya
  • 2 Answers

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Tuner Hum on Sony HT-DDW740


Check electrolytic capacitor C899 100uF 35V in STBY PCB
Cheers

Dec 02, 2008 | Sony HT-DDW740 System

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