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Need DX-40 part -- 40m osc. coil L2

Discussion in '"Boat Anchor" & Classic Equipment' started by K5DH, Oct 20, 2018.

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  1. K5DH

    K5DH Ham Member QRZ Page

    Anyone parting out a DX-40? I need the 40m oscillator coil, L2. The one in my rig has been damaged and repaired by Mr. Hammy Hambone.

    - OR -

    If you have the specs on this coil, I may be able to rewind it.
  2. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page


    I will have to look, but there is a good chance that I have the proper coil. If so, I am in the Collin County portion of Richardson.

    Glen, K9STH
  3. K5DH

    K5DH Ham Member QRZ Page

    Glen, any luck finding the DX-40 coil?
  4. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

    Not yet, but I have several more boxes of parts to examine.

    Glen, K9STH
  5. W7UUU

    W7UUU Super Moderator Lifetime Member 133 Administrator Volunteer Moderator Platinum Subscriber Life Member QRZ Page

    If all else fails, ping me. I'm traveling this week but when I get home, I can check my "parts unit" DX-40 if you've not found one yet. If you don't find one before Saturday, shoot me an email (QRZ email address). My DX-40 is pretty stripped so can't say for certain until I get home.

  6. N2EY

    N2EY Premium Subscriber QRZ Page

    The DX-40 oscillator coil is simply an adjustable inductor that broadly resonates with circuit capacitances. If a spare cannot be found, someone with a DX-40 or DX-35 could possibly measure it.

    I have an assortment of slug-tuned forms that could be of use.

    73 de Jim, N2EY
    AC0OB likes this.
  7. AC0OB

    AC0OB Subscriber QRZ Page

    Same here.

    I have a number of slug-tuned coils of various inductances.

    I have rebuilt a number of DX-35's and DX-40's and have actually had those coils out of circuit, but like a dummy I did not measure those coil values.

  8. K5DH

    K5DH Ham Member QRZ Page

    If someone could measure the inductance of a good coil, I can probably rewind it. My original coil form is undamaged, but the coil winding was damaged and has been haywired. It's clearly missing some turns, and although I get a shallow peak with it, it may have something to do with my inability to get any drive on 15m and 10m (that was suggested on another forum). Whether or not that coil is the source of my woes, it's obviously not right, and it can't hurt to make it right. I also have lots of coil forms in my stash. They come in handy!
    N2EY likes this.
  9. AC0OB

    AC0OB Subscriber QRZ Page

    Just to let you know, there are a number of design problems within the DX-40.

    One is the weak transformer barely capable of providing 150 mA,

    Second is the Oscillator and Buffer-Multiplier cascode (series) circuit which is part of the tuning problem even with a good 40m peaking coil,

    Third, the voltage on the Key is very high.

    In the PDF you will find some improvements to mitigate those prob,es.


    Attached Files:

    N2EY likes this.
  10. K1OIK

    K1OIK Platinum Subscriber Platinum Subscriber QRZ Page

    If and only if the others cannot help you I have a junk DX-40

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