Sherwood S-8910 Tuning meter adjustment

Discussion in 'Tuners' started by Eastham, Sep 10, 2017.

  1. Eastham

    Eastham More Class A than ever! Subscriber

    Messages:
    1,536
    Location:
    Liverpool, UK
    Hi, guy's. Hope I'm posting this in the right sub forum, as it is a receiver but I figure I should come here for help with the tuner bit..

    So here's my Issue, the Tuning meter seems to be out of alignment when off station, this was taken at the furthest end of the scale.

    DSC_0322.JPG

    The signal meter deflects to nil if I disconnect my ghetto antenna... But the tuning is always off center like that, I was looking around and found a adjustment for the signal meter and one for the tuning meter. My question is this normal for the tuning meter and if not can I adjust the tuning meter without all the special doodads that are required for most tuner ajustment, thought I'd ask here before I went and tried to cener the tuning meter with the pot and probably screw something up, I learned not to mess with tuner stuff without the proper equipment the hard way...

    Thanks.
     
  2. I LIKE MUSIC

    I LIKE MUSIC Super Member

    Per the service manual. If the center tuning meter is centered when the receiver is turned off.

    upload_2017-9-10_18-17-3.png

    T201 is the first adjustment.

    This can be done with the receiver tuned off station with the FM antenna input terminal shorted to prevent unwanted signals/electrical noise from pulling the center tuning meter off side. Adjust T201 for zero voltage as noted in the service manual.

    Then if needed adjust VR203 to center the center tuning meter.

    This should get your very close.

    Be sure to use the correct alignment tool for T201 (non metallic, correct size).
     
  3. Eastham

    Eastham More Class A than ever! Subscriber

    Messages:
    1,536
    Location:
    Liverpool, UK
    Thanks for the quick reply, when the tuner is off it falls to the middle, it's just when it's off station that it is off center but when I tune the tuner into a station perfect signal is at center of the meter, would centering the meter effect this?
     
  4. Eastham

    Eastham More Class A than ever! Subscriber

    Messages:
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    Location:
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    Just did the adjustment's and thank you so much! I swear the tuner is picking up more stations in FM only then it ever did! and the centered Tuning meter pleases me. If you don't mind explaining, what did making those adjustments do? I know T201 was way outta whack, 300mV!
     
  5. I LIKE MUSIC

    I LIKE MUSIC Super Member

    In simple terms, T201 controls the circuit that converts the radio signal (RF/IF) that we can not directly hear to an audio signal that we can hear.

    VR203 just calibrates the center tuning meter to read correctly when T201 is adjusted correctly.
     
  6. Eastham

    Eastham More Class A than ever! Subscriber

    Messages:
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    Location:
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    Ah, that's pretty neat. Suck's that my country is going to be killing FM in the coming years in favour of DAB like Norway.
     
  7. I LIKE MUSIC

    I LIKE MUSIC Super Member

    I am glad that you got it working.

    Too bad a about the transition.
     
  8. Eastham

    Eastham More Class A than ever! Subscriber

    Messages:
    1,536
    Location:
    Liverpool, UK
    Thanks again, for the help!
     

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