IC-751 Capacitor Array

Discussion in 'Radio Circuits, Repair & Performance' started by KD0WQP, Oct 10, 2017.

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  1. KA9JLM

    KA9JLM Ham Member QRZ Page

    I had a hard time posting a clear image.
  2. KD0WQP

    KD0WQP Ham Member QRZ Page

    Please excuse my ignorance, but I don't know what I'm looking at.
  3. KA9JLM

    KA9JLM Ham Member QRZ Page

    OK. Then it would be best not to adjust or mess with it.

    Sorry I was not much help for you. :(

  4. KD0WQP

    KD0WQP Ham Member QRZ Page

    I was able to zoom in a bit on my computer at work and now I see. Sorry for the confusion.

    Unfortunately I can't read the values of the various components, though I believe I'll be able to locate them in the service manual.

    I found C171 in the diagram - electrically far away from the circuit KA9JLM posted. It seems the capacitor array's function is to absorb spikes and/or interference that may be present on J7. I'm not sure, though, what the various acronyms on the diagram for J7 refer to:

    I'm beginning to believe N0TZU was correct when he suggested the poor carrier suppression could be due to the BFO frequency adjustment and, as such, isn't related to this bad capacitor array.

    I'll be replacing the old electrolytic caps with new ones with higher voltage ratings where possible.
    KA9JLM likes this.
  5. KA9JLM

    KA9JLM Ham Member QRZ Page

    Yes that is true.

    They keep HF noise off the interconnecting cables.

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