Thread: Valve PSUs
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Old January 28th 15, 12:59 PM posted to uk.radio.amateur,rec.radio.amateur.homebrew
Jerry Stuckle Jerry Stuckle is offline
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First recorded activity by RadioBanter: Oct 2012
Posts: 1,067
Default Valve PSUs

On 1/27/2015 11:18 PM, rickman wrote:
On 1/27/2015 10:37 PM, Jerry Stuckle wrote:
On 1/27/2015 9:47 PM, rickman wrote:
On 1/27/2015 7:59 PM, Ralph Mowery wrote:
"Roger Hayter" wrote in message
...
The oils in these old capacitors are often PCBs (polychlorinated
bi-phenyls) which are quite toxic. And they can leak slightly
even if
not visibly. So I wouldn't have them in a house occupied by any
non-old
non-amateurs. (A bit late for me to take up H & S on my own behalf.)


The PCB is not really that toxic. The problem is that it almost
does not
break down and gets into the food chain. You can touch it and even
get a
small ammount in your mouth without any harm to you. I don't mean
drink it,
but say you get some on your hand and lick a drop or two off your
finger.

Wow! What is your basis for saying that? Are you trying to say if it
doesn't kill you outright there is no danger?


He's right - it isn't really that toxic. It takes multiple exposures
over a long time to do any harm; getting some on your hands won't hurt
you. And even when it does harm you, it's not fatal. But it does cause
nervous system disorders.

There are a lot of things much more toxic you can easily find, even at
the grocery store. Drain cleaner comes to mind...


I asked what the source of this "fact" is. PCBs cause cancer. I have
never heard exposure to a carcinogen is safe as long as it is only for a
"short time" or "just once". Scientists have tried to establish
exposure thresholds, but this is speculation. The issue is how much
risk are you willing to accept rather than there being a threshold of harm.


Exactly. There are no thresholds because scientists cannot determine
how much is required to cause a problem. Unlike drain cleaner, for
instance.

And there are a lot of things which cause cancer. Even artificial sugar
has been blamed for causing cancer. So are you going to stop using
anything containing artificial sugar?

Just in the last few years I learned that we have so extensively
polluted our environment that it is not recommended to eat the fish from
nearly any river in the several US states where I live. This pollution
is largely in the form of PCBs. It is not from point sources that can
be cleaned up. It is widespread from small sources. Essentially, we
integrated this stuff into our lives to the extent that we are regularly
bathed in it.


More scare tactics. Pollution from medications (especially hormones)
being flushed down the drain is a much bigger problem. So I guess we
should stop taking any medications.

It seems people believe our persistent destruction of the environment is
something that happens somewhere else or the harm is overblown or that
it is something that we will have to deal with in the future. But this
is not true. The future is here and we are all living in the results of
our own ignorance.


Which still has nothing to do with PCBs - except for scare tactics.


BTW, unlike carcinogens, I can eat drain cleaner every day in adequately
small amounts. NaOH, Sodium Hydroxide. I have sodium in my diet as an
essential nutrient and hydroxide exists in all water solutions. NaOH is
not actually a poison, it is a corrosive. If you come into contact with
it in high concentrations it is harmful. In low concentrations it is
harmless in the true sense. I know this for a fact. Without harm, I
have handled NaOH in concentrations high enough that I can feel the
soapiness. So your analogy is poor.


No, you have sodium chloride (NaCl) in your diet, not NaOH. And even
small amounts of NaOH have been shown to be harmful - it is considered a
poison.

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