Broken VR-105

Discussion in '"Boat Anchor" & Classic Equipment' started by K9VKY, Jul 4, 2021.

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  1. K9VKY

    K9VKY Ham Member QRZ Page

    Does anyone have any information on the radioactive hazard from a broken VR-105 voltage regulator? I know if the envelope is intact, there isn't much of a hazard, but a broken envelope may be a different story. Thanks.

    Brian K9VKY
  2. KA0HCP

    KA0HCP XML Subscriber QRZ Page

    Don't lick the filament.

    Roll the broken tube in an old newspaper and throw away. Wash your hands. :)

    I cannot find any spec sheet that lists the VR-105 as being radioactive. However, many tubes used "Thoriated" coatings with Thorium Oxide on the filament to increase electron production. Thorium is a weakly radioactive element that in most forms emits Alpha radiation. Alpha particles can be stopped by the skin layers, paper, cloth etc, and travel only short distances (inches-couple feet) in air. No need to panic or evacuate the family.
    Last edited: Jul 4, 2021
    WA1GXC likes this.
  3. WA1GXC

    WA1GXC Ham Member QRZ Page

    I second the comment above. But to set your mind at ease, know the following:

    VR-105/0C3 is a really old tube type, used in WW II gear. The prototype big-bulb "shoulder" envelope is from ancient history; back then,
    radioactive isotopes were the realm of physics researchers and extraordinarily expensive, not to be used for pedestrian commercial purposes.

    In those days, as now, tube characteristics were standardized industry-wide across manufacturers by registering with the industry trade group--
    WW II era --Radio Manufacturers Association (RMA). That became RETMA (Radio-Electronics-Television Mfrs. Ass'n.) That became EIA
    (primarily what we see today with our new-old stock tubes--the basing diagrams are EIA designations in modern manuals) Electronic Industries
    Ass'n. And now EIA specs have become JEDEC specs.--Joint Electron Device Engineering Council. Basing, transistor case types (TO-92, TO66, etc.)

    As far as I'm familiar, the radioactive-juiced VR tubes came along with miniature 7-pin and sub-miniature types first showing-up in very early
    1950s. I have sub-mini Raytheon VR tubes (wire leads) from about 1953 for use in Army Signal Corps gear, stamped "Radioactive" The 7-pin
    "Hot" tubes would be used for military-contract gear and would be either an EIA type-number with suffix "W" or "WA" (militarized, ruggedized)
    or the military version of the civilian tube with a 4-digit 5000-6000 -7000 series type number.

    In our society we do a poor job of assessing risk. The really dangerous stuff (being on the road weekend evenings after midnight with
    1/3-1/2 of the cars on the road driven by impaired individuals) breezes right by us. If you really want to freak-out, take a look at the warning
    label on the underside of your home ionization-type smoke detector. Radioactive isotope of Americium with a half-life of decades.
    Bad news. Staying away from municipal dumps is probably more prudent than the worry about our tubes.

    And yes, thoriated tungsten filaments and beryllium-oxide from power tube ceramics not good for gargling.
    KI4ZUQ and N2EY like this.
  4. W3SLK

    W3SLK Ham Member QRZ Page

    If you have it broken somewhere like on the floor, take and make a loop of duct tape so that the adhesive side is out. Roll it over where the tube was broken and try to get all the particulates. Put it in a plastic bag and pass it in the trash.
  5. K9VKY

    K9VKY Ham Member QRZ Page

    Thanks for the reply and easing my mind. I slept better. Brian
    KI4ZUQ and WA1GXC like this.
  6. K9VKY

    K9VKY Ham Member QRZ Page

    N2EY likes this.
  7. K9VKY

    K9VKY Ham Member QRZ Page

    Thank you for your reply and background information. Brian
  8. K9VKY

    K9VKY Ham Member QRZ Page

  9. K9VKY

    K9VKY Ham Member QRZ Page

    Thanks for the reply, and clever idea for picking up bits and pieces. Brian
  10. K9VKY

    K9VKY Ham Member QRZ Page


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