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ARCHIVED FORUM -- April 2007 to March 2012
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This is the first Archived Forum which was active between 17th April 2007 and 1st March February 2012

 

Latest post 01-25-2010 1:14 PM by Dillen. 4 replies.
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  • 01-23-2010 7:01 AM

    Beocenter 7002 - Radio section - Sound quality

    Hello

    This morning I start to play on a Beocenter 7002, all pcb are recapped including the radio section. I have a problem on this pcb (PC2 - the one under the turntable), the signal is good, the receptions are good, not disturbed and frequencies are discriminated perfectly.

    BUT... the sound is loud, one channel is better but each if compared with another PCB installed in THE SAME beocenter is not good; using the better PCB the sound is powerful, warm and detailed on the high frequencies and both channels have the same output level.

    So I'm here to ask you a suggestion, I have the service manual, the frequencies emitter (88 - 108MHz) and a good oscilloscope (and 2 probe too... WOW! :)  ); the problem described could be solved with FM readjustment as described in the service manual?

    I need an encouragement Geeked this is my first time.....

     

    ciao ciao

     

    Eugenio

     

    This is my creature from the dust


    Watch Beocenter 7002 - Tonearm rewired - First check in Educational & How-To  |  View More Free Videos Online at Veoh.com

    Eugenio Colazzo

  • 01-23-2010 1:55 PM In reply to

    Re: Beocenter 7002 - Radio section - Sound quality

    Stereo decoder exchanged with the other from the good pcb, no good results.

    exchanged IC decoder output channel L & R , same result.

    Tomorrow I'll try to exchange the trimmers that lower the FM out signal.

    I'll keep you informed

    Hope this helps

    ciao ciao

     

    Eugenio Colazzo

  • 01-23-2010 2:20 PM In reply to

    • Dillen
    • Top 10 Contributor
    • Joined on 02-14-2007
    • Copenhagen / Denmark
    • Posts 5,008
    • Founder

    Re: Beocenter 7002 - Radio section - Sound quality

    The trimmers can be bad, that wouldn't be too surprising.
    You can lift out the signal path capacitors C37 & C38 and put the scope on pins 4 and 5 of the stereo
    decoder IC (respectively) and see if the levels are even and clean.
    If the tuner is misaligned, I suggest you first check for lose ferrite cores etc., also inside the FM front
    end metal casing, before adjusting anything. Some of the adjustable capacitors have round metal houses
    that can lose contact to the rest of the component. Spray cooler can also be good to help diagnose.

    Martin

  • 01-25-2010 12:28 PM In reply to

    Re: Beocenter 7002 - Radio section - Sound quality

    hehehe... hahaha... Martin once again!

    Thanks very very very much Martin, with your help I solved the problem, the fault was in the L2 coil, I exchanged the L2 and L3 position and found that the L2 is not good.

    Thanks again and again :)

    ciao ciao

    Eugenio

     

    Eugenio Colazzo

  • 01-25-2010 1:14 PM In reply to

    • Dillen
    • Top 10 Contributor
    • Joined on 02-14-2007
    • Copenhagen / Denmark
    • Posts 5,008
    • Founder

    Re: Beocenter 7002 - Radio section - Sound quality

    Well done !

    Martin

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