[sdiy] Tube amp cap discharge tool?

[Bob Weigel]

:-) I'd love to argue this the rest of my life..but we're talking a 
concept called 'straining out gnats' here.  I've done it for years.  
Nothing has been hurt.  Truly. customers would tell me if their amps 
dropped out. I'm really GOOD about that.  I find out what I'm doing 
wrong by writing rigorous invoices and I can tell if a capacitor were to 
have failed where I might potentially have done something to start it 
down the bad road.  As it is..no such incident. ALL CAP FAILURES in the 
decade I've been doing work on tube amps have been first timers.  Never 
has anything come into my shop with a dead capacitor that I had 
previously worked on except one or two where the customer said 'leave 
the old ancient ones, I dont' have money to fix now' and then they bring 
it back later.  I recall that maybe once. Nearly everyone here just has 
me replace old ones when in question.  ENd of story.  I have no further 
input to the topic. It works for me. If others choose not to do it 
fine.  My repair bills will continue to be cheaper then because I waste 
less time in the process of things like this. If you don't want your 
caps cro-barred..dont' bring the amp to me.  I'm fine with that :-)  -Bob

The Peasant wrote:

>>Sure but that's continuous duty. Where heat has time to build up and 
>>hurt things.
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>Discharging a DC filter capacitor by shorting it stresses it in a number of 
>ways, and it is stupid and dangerous to do this unneccesarily. There are 
>capacitors designed for this type of use, but certainly not old tube amp 
>capacitors.
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>> Let me give you an example. Ordered from Parts express.....
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>Bob, your long stories are sometimes interesting, but you appear to be ignoring 
>the important parts of what others are saying here. 
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>>Yeah and just pray the resistor isn't burnt out or you have a fault in 
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>the connections. 
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>You don't appear to be paying attention, Bob. As stated, you ALWAYS check the 
>capacitor with a meter before touching the equipment. Praying won't help.
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>>Like I just 
>>told John the ideal is put a current meter in line and all..
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>That is unneccesary and the peak current may damage the meter.
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>>However..while we're nit picking...
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>The only one that appears to be doing that is you. I'm just trying to 
>discourage practices that I have been taught by professionals to be dangerous. 
>I really don't want to see anybody here have any unfortunate accidents.
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>>When I see the energy being dissipated in the air, I know 
>>it's being taken off the internals of the capacitor which is a good 
>>thing.   Right?
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>No, not if you get injured or killed in the process.
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>>But like I say, I rest my case.  
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>On what? Your dangerous electrical practices based on your own "experience"? I 
>suggest you sign up for a course in electrical safety.
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>>On sheer chance guesses I'm 
>>horrible.  But when that background kicks in I usually make decent 
>>choices regarding the safety of components and materials.  
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>I prefer to base my safety decisions on knowledge gained from other *qualified* 
>professionals. Basing them on whatever sheer chance guesses haven't killed me 
>yet just doesn't cut it.
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>>I don't 
>>seriously believe anyone will hurt any capacitors rapid discharging them 
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>But you still don't get the point. It's a BAD IDEA for a number of different 
>reasons, and recommending it to others on a DIY list makes it very much worse. 
>And I do believe that you are wrong, somebody may well get hurt following your 
>advice, at the very least it will probably result in the damage of some 
>equipment. However, you don't appear to be hearing me or anyone else on this, 
>so this will be my last post on the subject.
>
>Please everyone, do not follow Bob's bad advice, always use an appropriate 
>resistor to dissipate capacitors, and always check ANY high voltage circuit 
>with a voltmeter before working on it.
>
>Take care,
>Doug
>______________________
>The Electronic Peasant
>
>www.electronicpeasant.com
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