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2015 W. Beaty

ETC corp. violet wand vacuum-tester, in cylindrical black phenolic case w/ribs, small black adjustment knob on one end, metal rod-point electrode on other
These handheld Tesla Coils from the 1950s are still being made, and repair-parts are still available. Today they're commonly used in physics and chemistry labs, science classrooms, and also used for finding pinholes in plastic tank liners. They create ozone and UV light, and are still found in use for skin treatments in some beauty parlors and barber shops. They originated in 1905 from the quack-medical arena, where they were claimed to cure everything from baldness to diabetes to cancer. Today (2015) the new ones cost $250 and up, but you can still find many antique versions on eBay. (After you've repaired these one or two times, you can buy cheap dead ones and get them working again.)

Common failures

  • No buzz when knob screwed in. Disassemble, and replace cord. Or, simply remove some of the several visible plastic washers from knob so it screws in further.
  • Buzz, but no sparks. Usually its a melted wax capacitor. Make a DIY replacement, or buy from ETP. Read TOTSEM hints

Secrets of disassembly

  1. Make or buy a custom 5/16 nut-driver
  2. Remove the nut found deep inside the HV socket
  3. Remove (unscrew) the plastic adjustment knob from its brass screw (*)
  4. Dig out the brown sealing wax from two brass screws on the flat base
  5. Remove the two screws
  6. Unscrew the entire Bakelite upper half
  7. Push out the buzzer assembly Be careful not to break thin wires between two coils (*)

Custom nut-driver

The small nut inside the HV socket is 5/16". However, the inside diameter of the HV socket is under 7/16", much narrower than any nutdriver tip's OD. This custom tool can be bought from Electro-Technic, or you can make your own by grinding down a standard 5/16" nutdriver's tip to under 0.42" 0.D.

Plastic adjustment knob

(*) The plastic knob is sometimes too tight to remove. Try adjusting it fully CCW (all the way out,) then twist hard so the plastic knob unscrews from its threaded post. If it's more than finger-tight, you'll need thin needlenose pliers or a small 11/64 wrench. Use one of these to grasp the flatted brass screw-shaft below the knob, then twist the knob CCW by hand or with pliers padded with paper towel. Don't squeeze the bakelite knob too hard!

Main Assembly Stuck!

(*) Sometimes the main assembly will not budge from the bottom plastic cylinder. It's a common failure: the wax capacitor adjacent to the 120V buzzer drive coil has melted, and glued itself to the inner surface of the Bakelite. Often it's possible to force a thin steak knife into the gap between the plastic and the wax glob. Work it along until you can pass the knife entirely around the main assembly. That frees it up.


These are the last of the quack-medical violet wands, the Bleadon-Dun Model Ten "Violetta." The brown phenolic case even still reads BD-10. These were saved from the 1951 FDA banning because all kinds of professional scientists and neon signmakers were using them to ignite plasmas in glassware, detect pinhole leaks in vaccum systems, or to serve as an inexpensive pre-built Tesla Coil for various instrumentation and in university classrooms. After Bleadon Dun Inc was no more, Electro-Technic products, Welch Scientific, and Chicago Electric Scientific Co. were selling them. Yet, the "alternative health" pamphlets for BD-10 can still be found, with claims to be cures for alcoholism, arteriosclerosis, cancer, TB, diabetes, deafness, epilepsy, whoopig-caugh, warts, and of course brain-fag (fatigue.)

Here's the first one, the B & B Coil of 1905, only $165 (so, over $4000 in 2015 dollars)


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