The short is noticeable with power obviously (I hear the arc and see a substantial drop in power), but w/o power also. You can here the plates rubbing over the small arc of turning. Once I noticed the arc under power, I have never powered it up again. I can hear the short easily. I have not identified where it is visually yet.
>Before doing any of this, however, it is a good idea to make sure that all of >the plates are properly aligned, i.e. parallel to each other with no obvious >bends, and that the adjustment of the fixed plates has not shifted. Typically >the fixed plates are adjustable while the movable ones are not. Evan, how do you adjust the fixed plates? This may be what I have done, experimenting loosening and tightening the nuts on the rear of the cap that hold the top two long bars. I can solve the short problem, but not by tightening down the nuts, only a partial snug fit seems to work. This does not seem a permanent fix, as I bet it will relax and cause the shorting again. Roger W5RDW ----- Original Message ----- From: K9sqg To: [email protected] ; [email protected] Sent: Thursday, June 09, 2011 5:25 PM Subject: Re: [Drakelist] L-7 Loading Capacitor Shoritng Roger, First order of business is to determine where the short(s) is taking place. Often when an arc occurs, a little pit builds up some of which goes below the surface and a little bit which goes above the flat surface on one or more fixed or variable plates. This in turn lowers the breakdown voltage which makes it easier to arc again. Once you locate where the problem areas are, then you can use either a flat/thin file or emery cloth to get a more uniform surface. Before doing any of this, however, it is a good idea to make sure that all of the plates are properly aligned, i.e. parallel to each other with no obvious bends, and that the adjustment of the fixed plates has not shifted. Typically the fixed plates are adjustable while the movable ones are not. Note too that dust or dirt can get the arc going too. Keep us posted. 73, Evan, K9SQG
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