At 02:03 18-02-02 -0500, Kevin Tarr wrote: >As far as safety, my first 'real' job ($5.80 an hour!) was fixing TVs and >VCRs. The second week I was helping put a new CR tube in a tv, in the >customer's house. We were pulling out the old CRT, and I stuck my finger in >the hole where the flyback HV lead went. WOW! My elbow put a hole in the >drywall and I hit a shelf that was full of nik-nacs. It shook very badly but >nothing broke. The guy I was helping had been a friend for 7 years, he was >laughing so hard he dropped the old CRT, obviously I wasn't holding it >anymore, and broke the yoke off.
Did you say "Hey, everybody! Watch THIS!" first? (For those who don't know, the rule-of-thumb for flyback voltage that I learned is 1kV/inch of diagonal measurement, e.g., a 12" CRT would have a 12,000-volt flyback voltage. And it's stored in a capacitor, so--as Kevin noted--it can get you even when the set is turned off and the power is disconnected. Which is the point behind the earlier safety warnings about working on such equipment. There _is_ a proper, safe way to discharge the flyback voltage capacitor, but it does _not_ involve putting your finger in the hole . . . ) <snip accounts of other great moments in workplace safety ;-) > I personally have mostly been either careful or lucky (probably more of the latter) in that the only casualties of most of my electrical misadventures have been fuses and nerves. For example, when I was an undergraduate, I worked for a while in the nuclear physics lab (that in itself is a combination that ought to inspire feelings of confidence ;-) ). One day, I was supposed to wire up a delay circuit for the main power switch to the cyclotron that would make the alarm sound for the safety-regulation-required X seconds before the power was applied. One of the faculty handed me a hasty sketch of the circuit diagram as he envisioned it drawn on the back of an envelope. I already knew enough about electronics to not solder anything in place until I had tested it, if possible, so I grabbed some jumper cables and breadboarded the circuit he had diagrammed. When I applied the AC power, there was a spark that was literally a foot long (30cm for Alberto), and the lights in half the building went out. Needless to say, the circuit diagram required some slight revisions before it could be hardwired . . . (BTW, by that time, the "artist" who had drawn the diagram was nowhere on campus.) -- Ronn! :)
