and while I know we all learn, and are taught about treating electricity
with caution, and respect, and that how it takes x amount of tiny current at
x amount of voltage to potentially stop the heart etc etc, you can still
grab onto an open 110/120VAC line and it'll only give you a bit of a
jolt...I've gotten that so many times I can't count from bad wall plugs and
bad chord ends etc...try plugging the vehicle in at minus 25 when the female
end of the extention chord has been lying in the snow and you have to get
rid of the snow plugging up the plug to insert the male part from the
vehicle...you get jolted a few times doing that let me tell you...though
after a few minutes, your fingers are numb enough from the cold that you
don't really feel it anyway hi hi.
at any rate, when your working on devices that have a step down transformer
in them, best practice is to unplug, or turn the power off if you don't need
the device to be operational while your working on it...however, if it is
unavoidable, like in this situation, there's not much harm in getting a
little buzz if you touch the wrong spot.
Also, if you unplug the thing and explore around inside before working on it
while it's live, you can orient yourself to where the higher AC voltage
might be located. These days, most components have some sort of insulation
around the high voltage contact points...such as at switches and where the
AC connects to fuses and the main transformer.
Usually these things are designed with all the high voltage, as in 120VAC,
connections set up on one side of the PCB...sometimes I just put electrical
tape or duct tape over these connections if they are open so I don't touch
them or short them or something like that.
It's easy to tell these connections because the wire is generally pretty
thick compared to other wiring in the device, and you can trace the wire and
tape off solder points or whatever.
there is always a way, if there is the will.
I've been working on a solid state guitar amp lately. In order to trouble
shoot the problem, it has to be turned on and operational in order for me to
figure it out. I traced all the hot spots and covered them with tape...and,
I know where the hot spots are located on the board so I stay away from that
area as much as possible. I also taped the edges of the board and the
chassis edges so nothing will short to ground by accident while the board is
floating around unanchored.
I did this of course after I shorted some hot point to the chassis, which is
ground in this thing..and had a little flash and puff of smoke...thankfully
nothing blew and all is well, other than the original issue.
So, respect power, and maintain considerate caution, but don't fear what
isn't there.
I mean, don't stick your tongue on a live 120Vac source or anything, but
getting a tingle in your fingers from accidentally touching it isn't going
to hurt you or your equipment in any severe manner.
Allot of guys will use a rubber matt on the desk and floor while working on
anything that is live...but again, not all that is necesary unless your
dealing with allot of humidity in the air or you have a real high ground
potential or high electrical resistance in your body.
everyone will react differently to electricity as well depending upon their
biological make up.
73
Colin, V A6BKX
----- Original Message -----
From: "Butch Bussen" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Monday, February 28, 2011 5:03 PM
Subject: Re: RFI Saga continued
> You're making a mountain out of a mole hill. It won't bite you!!!
> Turning the switch on does nothing but connect the primary to a c. Just
> unplug and it will bleed off in half a minute or so. I've worked on
> them plugged in for years.
> 73
> Butch
> WA0VJR
>
> On Mon, 28 Feb 2011, tom behler wrote:
>
>> The other thing I was thinking of doing was unplugging the power
>> supply,
>> letting it set for a while, and then turning the switch on, in the hopes
>> that this would help discharge the capacitors too.
>>
>> Any thoughts?
>>
>> 73 from Tom Behler: KB8TYJ
>>
>> ----- Original Message -----
>> From: "Butch Bussen" <[log in to unmask]>
>> To: <[log in to unmask]>
>> Sent: Monday, February 28, 2011 11:57 AM
>> Subject: Re: RFI Saga continued
>>
>>
>> The thing will discharge itself if you let it set a short while. Second,
>> there is only 24 volts or so on a cap and I've worked on them hot and as
>> long as you stay out of the primary 110 side, no worries. It won't zap
>> you.
>> 73
>> Butch
>> WA0VJR
>>
>>
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