[sdiy] Tube amp cap discharge tool?

[Bob Weigel]

Yeah and just pray the resistor isn't burnt out or you have a fault in 
the connections.  Then at the pearly gates you'll be reminded "...why 
didn't listen to Bob when he said 'let 'er rip'??"  :-)  Like I just 
told John the ideal is put a current meter in line and all..but that's a 
pretty elaborate setup and very few are going to go to that effort for 
something used so seldom.  The danger of all this stuff is..it's more 
unreliable possibilities in between your life and possible death.  Good 
insulated handle..cheap blade....let 'er rip and wear eye protection on 
smaller caps is still my recommendation.  I always have glasses on so I 
often forget to mention that in casual discussion.  I've actually BEEN 
SHOT by a transistor that shorted onto the case inside a TO3 can!  And 
another time I got peened in the head by a piece of a TO220 output 
device.  Eye protection is always a good thing when around high power 
circuitry. -Bob

KHeck73 at aol.com wrote:

> Just another thing to point out... It takes time for the capacitor to 
> drain. So, leave the resistor or short connected for a minute or 
> two, then check with a voltmeter to be sure it's dead. The larger the 
> capacitor, the more volume there is in the dielectric. I remember in 
> my youth fooling with a big electrolytic and making the bang with a 
> screwdriver. I could pop it several times, even after holding a direct 
> short across the capacitor for several moments. With a direct short, 
> the capacitor can reverse charge itself from the rush of extra 
> electrons overshooting from one plate to the other. Part of 
> the charge can still be there unless it has time to completely 
> equalize. Ben Franklin sort of stuff.
>  
> -Karl.
>  
> In a message dated 5/19/2005 6:31:16 P.M. Eastern Daylight Time, 
> ecircuit at telus.net writes:
>
>     For the small amount of time that it would take
>     to wire up a clip lead with a discharging resistor, it really
>     makes sense to
>     play it safe. I certainly wouldn't want anyone working on my
>     equipment to start
>     shorting out power supply capacitors.
>
>