Path: utzoo!attcan!uunet!husc6!bloom-beacon!mit-eddie!bbn!uwmcsd1!ig!agate!helios.ee.lbl.gov!nosc!ucsd!ucsdhub!hp-sdd!hplabs!hpl-opus!hpccc!lkraft
From: lkraft@hpccc.HP.COM (Lyle Kraft)
Newsgroups: sci.electronics
Subject: Re: Baffling Buzzing Boob tube
Message-ID: <4990004@hpccc.HP.COM>
Date: 20 Jun 88 14:59:41 GMT
References: <1791@loral.UUCP>
Organization: HP Corporate Computing Center
Lines: 23


 
    Sounds like some tweaking of the sound detector quadrature
    coil is in order.

    Scenes with a lot of vertical detail generate a large amount 
    of high frequency video signals which interfere with the
    sound subcarrier. Alignment of the sound detector becomes
    more critical under these conditions. Sometimes the sound
    detector will drift out of tune with age or heat and cause
    this problem. The worst that may be wrong is that the video
    IF strip is out of alignment, but this is highly unlikely.

    To adjust the detector, find the correct coil in the sound
    circuitry, either a metal can or a plastic tube with wire
    wound on the outside, and find the correct alignment tool
    to adjust the internal tuning slug. Tune you set to a strong
    station with a program showing a lot of detail, like
    Jeopardy :-) , and adjust the coil for maximum volume/minimum
    buzz.

    If your set has the "works in an IC" type of sound system, ignore
    all of the above.