[sdiy] HV cap discharging re-revisited

[Travis Shire]

A 10k 1/2w on a gator clip works just fine. Good idea to leave it clipped in
until the works done. Old caps with bad dialectric absorbtion can start
creeping back up in voltage when the gnd path is removed.

>
> I am in the process of designing a new amp in the near-gutted chassis of a
> Wards Airline radio that uses a 6V6-GT output tube and a 5Y3-GT rectifier.
> I'm sure I've mentioned it a few times...
>
> Today I had everything disconnected from the power supply except the first
> filter cap. to see what recified voltage coming off the cathode was (about
> 330VDC after warm-up). I had planned to discharge the cap using an
ordinary
> lightbulb - I even prepared a special socket with big alligator clips (too
> big really). So when I used it, nothing happened. And I should have known
> nothing would happen because I let it sit for 2 hours, turned off
connected
> to my DMM, which showed 0V right before I disconnected it. So, duh! If I'm
> not in a big hurry, can't I just let my DMM discharge the cap and I can
> watch it go to 0-ish. What IS a safe DC voltage to let a cap get to? I
mean
> you can melt metal with 9 volts and a 50,000 uF cap. My guess, for the
> circuits I'm working with, is below 50 VDC. But you can still really feel
50
> volts - nothing like getting bit by 400 volts (which I have - fortunately
I
> was not grounded and it was an ever so slight brush to a charged cap in a
> circuit that was turned off - so it may not have been the full voltage...)
> and REALLY nothing like getting bit by a mini-bike magneto (that fucking
> stings!).
>
> What DID we decide was the best way to discharge caps - if one's in a bit
of
> a rush, that is. I remember someone offered their ex-wife?
>
>
> cheers,
> aa
>
>
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