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Marantz 2220B tuning capacitor question

Discussion in 'Marantz Audio' started by Beamer302, Nov 29, 2017.

  1. Beamer302

    Beamer302 AK Subscriber Subscriber

    Messages:
    259
    Hi all, I am working on a Marantz 2220B and I want to know the trimming capacitor layout that is on top of the tuning capacitor . I believe that starting from left to right the first ,third, and fifth trimmers are for FM . Which one is for the RF circuit. Which one is for Antenna. The one on the far right is soldered and I am guessing that is an oscillator trimmer . tuning capacitor.jpg Also in step 3 of the FM alignment instructions on the service manual it says to adjust trimming capacitor C118 after tuning to 109MHz with FM signal generator. Where the heck is C118 ? I have included a picture of the 2220B tuning capacitor.
     

     

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  2. chazix

    chazix AK Subscriber Subscriber

    Messages:
    1,154
    Location:
    Groton MA
    I can't discern the tuning cap vanes, but the more widely-spaced vanes are the FM ones, so the trimmers directly above the wide-spaced vanes are also FM. I think it's safe to say that the leftmost FM trimmer in your picture would be for the antenna circuit. The soldered-on part is indeed the oscillator trimmer, which is C118.

    HTH,

    chazix
     
  3. Beamer302

    Beamer302 AK Subscriber Subscriber

    Messages:
    259
    Thanks, The widely spaced vanes of tuning capacitor are under the 1 , 3 & 5 trimmers . So those would be for FM . The # 6 trimmer with the wire attached to it is coming from the AM loop antenna. Would that make the # 5 trimmer the FM antenna trimmer as it is in the same section of the tuning capacitor as the # 6 trimmer which has the antenna wire attached to it ?
     
  4. chazix

    chazix AK Subscriber Subscriber

    Messages:
    1,154
    Location:
    Groton MA
    I believe you'll find that the connections at the bottom left of your picture lead to the FM antenna, so I still think the #1 trimmer is for the FM antenna circuit. The #3 and #5 trimmers would be for the RF stages that come in between the antenna stage and the mixer/output stage.

    Although I haven't reviewed the alignment instructions, I would think that the #1/3/5 trimmers are all adjusted in the same way anyhow, no?
     
  5. Beamer302

    Beamer302 AK Subscriber Subscriber

    Messages:
    259
    Thanks , I have been looking over the schematic and service manual and this is becoming clearer now . I agree they all get trimmed the same anyway .
     
  6. tranguru

    tranguru Active Member

    Messages:
    201
    Location:
    Brussels
    Just curious - what are you trying to do - what is the matter the tuner. In my experience this rarely goes wrong.
     

     

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  7. Beamer302

    Beamer302 AK Subscriber Subscriber

    Messages:
    259
    The FM pulls in signals a bit on the weak side . The stereo light comes on but only on two very strong stations. There are many stations down here in South FL. It tracks just fine so there was no need to mess with that part of the alignment.
     
  8. thxdave

    thxdave Lava Lamp repairman

    Messages:
    408
    Location:
    Florida
    What kind of antenna are you using?
     
  9. Beamer302

    Beamer302 AK Subscriber Subscriber

    Messages:
    259
    It's a Dipole Flat plastic style . I have aligned a few other Marantz units and I have found that some do indeed need an alignment . This one just seems to not trigger the stereo light as it should . It does come on when tuned to a very very strong station and the voltages on the transistors H207, H208 and H209 are within the range of the schematic. When tuned to a strong station it does not come on. It has been recapped completely . I'll keep poking around ....
     
  10. kstlfido

    kstlfido New Member

    Messages:
    26
    Hi Beamer302- Almost the exact same scenario- I can only get two stations to lock onto stereo, both at the low end of the band. Plenty of strong stations here to choose from. I too, am trying to find C118 as referred to in the alignment instructions. So, it is the soldered trimmer? Did you unsolder and trim it? How did your alignment go? -Kent
     
  11. Beamer302

    Beamer302 AK Subscriber Subscriber

    Messages:
    259
    I did not unsolder and mess with C118 . Adjusting the trimmers and coils for each stage brought the FM light on for most stereo stations. I repeated each step over and over till no adjustment was necessary for each stage .
     

     

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