Cap discharge

[sumitomo]

There are some guys here that like to toy with amphs (me for one) so I thought I post a safety vid. Sumi:DRg3-dZC5Fww&NR

[Ch0jin]

Ahh so using a wet finger is the -wrong- way. I wondered what I was doing wrong :)

Just jokes. Good little vid there. Man those filter caps looked old though. Like wax paper and oil type caps maybe....

[sumitomo]

I was discharging them and doing the one hand probe but I wasn't checking them after I discharged them to be sure.I've been thrown about 10ft once when I got shocked.There was an ice storm and a branch fell and bent the weather head on my house,the power company came a fixed it.The was a strange power surge after that,it would blow light bulbs out and trip breakers.One time when I went to reset the breakers WHAM! when I touched the breaker box (lucky I had tennis shoes on)it threw me across the yard.The next day when the power company came out(cause I wasn't gunna touch that thing again) Well the ground wire came pulled out when the weather head bent and we couldn't see that it was behind the meter so yep I was ground and that was 220v.So I learned to have respect because that was AC and it is the DC that could kill ya.Sumi:D

[duhvoodooman]

So I learned to have respect because that was AC and it is the DC that could kill ya.Sumi:D
AC can kill you, too, it's just that DC does it more efficiently! :eek:

Good video for me personally, since my Trinity 18W amp kit is "in the mail"....

[sumitomo]

I agree that AC can kill and it could have killed me if I had been barefoot or in my sandals but that day I was wearing tennis shoes.Sumi:D

[Ch0jin]

Yeah I've been zapped a few times myself, everything from low voltage-high current burns (12V car batteries are more dangerous than you might think) to in excess of 25KV from CRT TV's.

Then again I did work for 10 years in the electronics repair industry so, like my counterparts in the game, I tend to wear those wounds as a badge of honor :)

Seriously though, the checking after you discharge bit is very important.

Large caps, exactly like the ones you find in a tube amp WILL, over time, charge themselves back up somewhat after you have discharged them. When working on an amp you could probably leave your filter caps shorted with a clip lead whilst working on it to ensure you don't get zapped, but you had better remember to remove that lead when you fire it up. Unpleasant things can happen if you turn on an unfused amp with the filter caps shorted to ground (trust me....) I wouldnt worry about measuring the voltage as a test though, just "Zzzzzzt" short them out before you touch anything and if you get up to have some lunch and come back an hour later, discharge them again.

Incidentally, the worst offenders in this regard (that I've seen anyway) are CRT's. They are gigantic caps themselves and the just -love- to recharge themselves from the air. The caps in MWO's are killers too. Forget 600V caps in amps, these puppies run into the KV range.

[jim p]

This brings up the fight that Edison had with Tesla with Edison fighting for DC while Tesla was for AC. According to the Wikipedia section (http://en.wikipedia.org/wiki/War_of_Currents ) on the AC versus DC debate AC will mess with your heart more then DC. What you want to avoid the most is current passing near your heart. Do a search on Edison and Tesla it is an interesting story with Edison electrocuting animals to show AC was dangerous. Both AC or DC can kill you but if the current just passes through your arm you heart should hopefully be OK, but still worth avoiding.