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Ceramic doorknob capacitor sources

Discussion in 'Amateur Radio Amplifiers' started by WB2JCC, May 7, 2019.

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  1. WB2JCC

    WB2JCC Ham Member QRZ Page

    I am trying to repair an Yaesu FL2100b that stopped functioning on 75/80 meters. I found that the 300 pF, 3000V doorknob cap was cracked and had a small burn spot. I found one on ebay that was a 300 pF, 12,000 volt. I ordered it but its physical size is making it virtually impossible to install.

    I would like to know if there is a better source for comparable caps, or if another type can be used.

    Thank you for your kind assistance

    73
    Matty
    WB2JCC
     
  2. KA0HCP

    KA0HCP XML Subscriber QRZ Page

  3. WB2JCC

    WB2JCC Ham Member QRZ Page

    Thank you!

    Matty
     
  4. W1BR

    W1BR Ham Member QRZ Page

    RF current rating is very important for RF applications. Make sure the doorknob is properly rated... many have very poor current ratings for RF.
     
  5. W9GB

    W9GB Ham Member QRZ Page

    The Yaesu FL-2100b replacements must meet a number of specific electrical criteria:
    Capacitance Value and Voltage Rating as well as physical criteria to fit in available space: Thickness(width) and Diameter (to avoid ill-advised hacks).
    The chosen model (product) should be designed for RF applications.
    ==
    Soviet surplus and Chinese manufacturing, in the past, have been the “low cost” substitutes.
    However, those bargain pricing are now ending, HEC is the United States mfg. and Cermatec is the German manufacturer.
    ==
    High Energy Corporation (HEC)
    http://catalog.highenergycorp.com/category/ceramic-capacitors

    High Energy Corp.
    PO Box 308, Lower Valley Road
    Parkesburg, PA 19365
    phone: +1-610-593-2800 , fax: +1-610-593-2985
    sales@highenergycorp.com
    ==
    HVC Capacitor Manufacturing
    High Voltage RF Capacitors
    http://www.hv-caps.com/products/H-F-RF-Power-Capacitor/2012/0223/106.html

    HVC Capacitor Manufacturing Co.,Ltd
    9B2, TianXiang Building, Tianan Cyber Park
    Futian, Shenzhen, P. R. C
    Tel: +86-755-61167757 Fax: +86-755-23997722
    Mobile: +86-13689553728
    E-mail: sales@hv-caps.com , hvcaps01@gmail.com
     
    Last edited: May 13, 2019
    KD0CAC likes this.
  6. W9WQA

    W9WQA Ham Member QRZ Page

    my barn,warehouse, if all else fails...
     
  7. WB2JCC

    WB2JCC Ham Member QRZ Page

    Hi Tom,
    I believe all else has failed! I checked the vendors that the other kind folks had posted, checked ebay again and many other places and cannot find a capacitor that that will both physically fit and have the correct capcitance and rf and volatage ratings.

    Please tell me if you have something appropriate that you might be willing to part with ( for the right price, ofcourse)

    Thanks

    Matty
     
  8. G3YRO

    G3YRO Ham Member QRZ Page

    Bear in mind that the capacitor doesn't HAVE to be bolted to the chassis . . .

    When I modified my FL2000B to cover 160m, the big doorknob padder I added was just hanging in mid-air . . . so you could do the same if you can't find one to fit in the original position of the 80m padder.

    Roger G3YRO
     
    K7TRF likes this.
  9. W1BR

    W1BR Ham Member QRZ Page


    I have some of those parts in stock (from the old Norbill's repair dept. in Holyoke, and I may have a few NOS on hand. What was the cap values? But, those caps were noted problem areas in that amp.

    Pete
     
  10. WB2JCC

    WB2JCC Ham Member QRZ Page

    Hi Tom,

    The caps I am looking for are 300pF, 3Kv. + 10%. My email is list on my page and here it is again
    wb2jcc@gmail.com. Feel free to contact me directly.

    Thank you very much for checking I really appreciate it.
    Matty
     

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