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Well, it finally happened, I got shocked....

Discussion in 'Ham Radio Discussions' started by K8CCA, Mar 1, 2021.

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  1. XZ2A

    XZ2A Ham Member QRZ Page

    My most surprising shock occurred when I was standing atop a metal water tank tower in Thailand, holding a 2-element, 6-meter yagi in my hand. As I manoevered the Yagi, one of the metal elements made contact with a bare wire from the 220 volt water level sensor. I'm getting shocked, and was about to throw myself off the metal tower and onto (through?) the roof of the house below!! Luckily, the top of the yagi moved and the circuit was broken....
     
    N1VAU likes this.
  2. WA9SVD

    WA9SVD Ham Member QRZ Page

    Glad you are OK, and hope you learned your lesson! Some don't survive their first "lesson" or live to tell about it. Glad you are OK.
     
  3. W9BRD

    W9BRD Ham Member QRZ Page

    My could-have-been-dangerously-different story involved a Heath HW-16 transceiver, which one day simultaneously developed two symptoms: (1) Its AF-GAIN-control-operated POWER switch stopped working but (2) reversing the rig's non-polarized power plug in the wall socket would turn the rig on and off.

    Investigation revealed that the armature of the rig's pot-mounted power switch had broken free of its mounting pivot and jammed against the pot's common-to-chassis metal shell while remaining electrically connected to its pivot through its spring, and hence to the return lead of the rig's power transformer's primary winding. The transformer primary return was therefore hardwired to chassis:

    hw-16_short_361x410.png

    I had safety/RF-grounded the HW-16 to the frame of my apartment's electrical baseboard heater. Therefore, with the rig's power-transformer primary return hardwired to chassis, inserting its power plug such that the 120-V-ac HOT wire fed the circuit-breaker side of the transformer primary would power up the rig, whereas reversing the plug put ac-hot on the open POWER switch stator.

    Had the rig chassis not been safety-grounded or grounded through another piece of gear, the rig chassis would have been hot with 120-V-return ac, and depending on exactly in which sequence I disconnected the rig for inspection could have determined whether I took the primary return current from hand to hand -- an even more likely scenario had the rig instead, or also, been grounded through its antenna connection or connection to another piece of gear, such as a keyer or VFO. (With the rig grounded one way or the other, had the switch armature been jammed to chassis on the ac-line side of the switch, an immediate hot-to-chassis-to-ac-common fault would have occurred -- or not -- and blown an ac-panel fuse or popped a breaker depending on how the ac plug was inserted at switch-breakage time.)

    It make a good detective story, but it could have been someone else's detective story had things gone just a bit differently.
     
    Last edited: May 1, 2021 at 1:32 PM
  4. K3EY

    K3EY Premium Subscriber QRZ Page

    I got the shock of my life in the high voltage and section of a TS830S which hurt like I couldn’t believe or believe I was still alive. Stupid stupid stupid is what I was. I have never worked on anything live since.
     
  5. W9BRD

    W9BRD Ham Member QRZ Page

    So, Circuit Detectives, here's a hot one from October 1967 Popular Electronics, the Hart-65 transmitter:

    1967OctPEHart65Schematic.jpg

    Maybe you built one; good, you survived. Keying the oscillator tube's grid-resistor (R1) return and the cathode together is not cathode keying; it's B-minus keying, which, with the key up, places the cathode, grid, and the grid-connected terminal of keying-adjustment trimmer capacitor C1 at full B+ above common. Only the tube's heater-cathode insulation keeps the full B+ voltage off both sides of the keying line, relay K1, and the heater winding of the power transformer.

    Part of the reason cathode keying has a bad rap is that many, many, many hams, including some responsible for circuits in major ham publications, did not know that connecting a tube's grid return to cathode and keying both is B-minus keying and not cathode keying. Cathode keying puts only a tube's cutoff voltage at the key; B-minus keying, the tube's full plate voltage.
     
    W9JEF likes this.
  6. N1VAU

    N1VAU XML Subscriber QRZ Page

    In my early 20s I was a TV repairman. The old Magnavox hybrid chassis were dying off but some customers keep them going because the cabinet was so beautiful. I was working in the customer's home on the coffin model with the radio, record player and TV in a coffin sized cabinet. The only way to adjust for best picture was to do it while it was operating. Being this was a large cabinet I couldn't get my portable mirror set up so I could reach the internal adjustment and see the pictures at the same time. I was in an awkward position when my hand got snagged on one of the screen controls. It poked a couple of holes in my palm and smoked while I squirmed to free myself. After the smoke cleared I measured 170v where I got hung up.

    I made sure that never happened again!!!
     
  7. W9JEF

    W9JEF Platinum Subscriber Platinum Subscriber QRZ Page

    When I was maybe 7, trying to pull a plug out of an outlet, got my thumb and forefinger across the AC.

    Worst case was at age 15, when I got pissed at my Command transmitter, and hit the open top, contacting the plate caps of the 1625s.

    Last time I got really bit was doing film camera repair. First thing you need to do after opening them up, is discharge the HV cap.

    Oh wait... just in the past couple years, got a minor jolt, likely from nearby lightning, while handling my antenna circuitry.

    EDIT: Just remembered the time, as a teenager, working outdoors, shocked by a poorly insulated electric drill.

    73,
    Jim . . . . . . . . . EARTH: LOVE IT OR LEAVE IT
     
    Last edited: May 1, 2021 at 3:20 PM
  8. AF5XF

    AF5XF Ham Member QRZ Page

    my biggest shock occured in a FT-101 I was trying to service. I had the bottom cover off and was working in the driver stage section when I (stupidly) not paying attention inserted a finger in one of the tuning capacitor slots for the driver. I got a pretty good shock off the +400v on the plate of the 12by7a. I've also had several 120v shocks but nothing like this one.
     
  9. G4OBB

    G4OBB Ham Member QRZ Page

    OMG...reminds me of when I was a kid of 12, playing around with a big mains powered supply...big potted transformer Tube rectifer and some large capacitors.....turned it off, for reasons still unknown, touched one output terminal...nothing! Touched other terminal...nothing....touched them both together..........................................BAM......picked myself up form the wall on the other side of the room.....remember a big yellow flash in my head....felt strangely elated.....weird!
     
  10. N8ZL

    N8ZL Ham Member QRZ Page

    I worst I got shocked was from making an adjustment on a Johnson Invader, my pinky finger came in contact with the plate cap of one of the 6146's. It hurt so bad I didn't go back to the radio room for a week. It burned a hole in the nail and took months to heal. Lesson learned, I had a bad day at work which was still on my mind, it was late at night and I was tired. Bad combinations when working around rf and HV.
     

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