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Old July 3rd 09, 01:02 AM posted to rec.radio.amateur.boatanchors
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Posts: 80
Default AR88 enthusiasts in Australia

Sorry Richard. Did not mean to alarm you. In fact there has been some doubt
about whether the material in the AR88 caps is PCB and indeed there's even
some controversy about how dangerous PCB is. But I personally (nervous
fellow that I am) prefer to play safe. I even have cards all over my
workbench reminding me that there are lethal voltages in an AR88. Trouble
with modern electronics is we get used to handling 5volts with impunity and
it is as well to rekindle the caution we used to apply (or should have) in
the valve days. For those who want to read up on PCBs try the writings of
Barry Ornitz who is a very knowledgeable chemical engineer.

"MoiInAust" wrote in message
...
Thanks Richard

But not only does it smell bad, it is positively dangerous! Believed to
be PCB oil which is carcinogenic. (BTW, they are not electrolytic but oil
filled paper caps). I have received comprehensive advice on disposing of
the leaky capacitors (should I say condensers?) safely and in accordance
with health regulations. They MUST not be just thrown into the gargbage. I
will be removing mine according to that advice. Either I will obtain
genuine replacements or I will have to do with tagstrips and indivdual
caps. Ouch! I know that's sacrilege but its the lesser of the two evils if
new 'originals' can't be found --- and by the way I may have found them!

"Richard Knoppow" wrote in message
m...

"MoiInAust" wrote in message
...

"Firebottle3" wrote in message
...
On Jun 28, 8:07 pm, "MoiInAust" wrote:
Are there any AR88 enthusiasts in Australia on this group?

Anyone (in any country) know anything about the RAF variant (R1156A I
believe)? It appears the same as the normal one except has an earthing
plug
for the mute fitted to the rear (a plque syas fopr the Control Unit
type
88). I've just acquired one with leaking bathtub condensers.

Where do the AR88 people hang out please?

Look he http://mailman.qth.net/

Click on directory scroll down to RCA join for free or look at the
archives.

Thanks Tor and Richard

I was aware of both!

The bathtub caps can often be "rebuilt" if you want something
original looking. You need a large soldering iron to get the bottom off.
It isn't a matter of heat but of mass to be able to get the thing off.
They were probably soldered on by dipping in a solder pot. Once the
bottom is off you can melt out the potting compound. Most of this is a
wax mixture which will flow out. Most of it smells pretty bad so do this
outside. The original cap can then be removed and replaced with a modern
one. That can be held in place with a bit of silicon rubber or even some
of the original potting compound melted back in. The bottom can be tacked
back with the soldering iron.
I think this is a lot of work in the interest of appearance but a lot
of people care about that.
If you have one bad electrolytic look our for others of the same
type.



--
Richard Knoppow
Los Angeles
WB6KBL






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Old July 3rd 09, 04:14 AM posted to rec.radio.amateur.boatanchors
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First recorded activity by RadioBanter: Oct 2006
Posts: 527
Default AR88 enthusiasts in Australia


"MoiInAust" wrote in message
...
Sorry Richard. Did not mean to alarm you. In fact there
has been some doubt about whether the material in the AR88
caps is PCB and indeed there's even some controversy about
how dangerous PCB is. But I personally (nervous fellow
that I am) prefer to play safe. I even have cards all over
my workbench reminding me that there are lethal voltages
in an AR88. Trouble with modern electronics is we get used
to handling 5volts with impunity and it is as well to
rekindle the caution we used to apply (or should have) in
the valve days. For those who want to read up on PCBs try
the writings of Barry Ornitz who is a very knowledgeable
chemical engineer.

Well, I'm not very alarmed:-) PCB's are considered
serious environmental polutants and are toxic, especially
when exposure is chronic. The may be carcinogens but when I
looked this up just a few minutes ago, it does not seem to
be well established, I had thought it was. If you have to
clean it up wear _nitrile_ gloves since the stuff will
penetrate latex. There is certainly no reason to replace
intact PCB filled capacitors if they are not leaking and are
OK electrically.
PCBs began to be used to replace mineral oil in
capacitors and transformers in the 1930s because they are
not inflamible and have better electrical characteristics.
They were sold under many trade names but its possible some
other substances may also have been marketed under those
names. In capacitors and transformers such names as Askarel,
Pyranol (General Electic), Dykanol (Cornel Dublier), and
many others.

--
Richard Knoppow
Los Angeles
WB6KBL




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Old July 3rd 09, 12:41 PM posted to rec.radio.amateur.boatanchors
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First recorded activity by RadioBanter: Aug 2008
Posts: 80
Default AR88 enthusiasts in Australia

Spot on with the nitrile gloves, Richard, as advised by Barry the chemical
engineer. I bought some this morning. Two of my bathtubs are leaking oil
badly and they will have to go. Per advice they will go in a sealed marked
container to the council hazardous waste collection.

I certainly won't be doing a repot job! Either I'll obtain the replacements
I think I've found, or in the interests of safety I'll put up with a non
standard change and mount individual caps on tag strips. If it turns out
they must be screened then I'll fabricate new tubs.

"Richard Knoppow" wrote in message
m...

"MoiInAust" wrote in message
...
Sorry Richard. Did not mean to alarm you. In fact there
has been some doubt about whether the material in the AR88
caps is PCB and indeed there's even some controversy about
how dangerous PCB is. But I personally (nervous fellow
that I am) prefer to play safe. I even have cards all over
my workbench reminding me that there are lethal voltages
in an AR88. Trouble with modern electronics is we get used
to handling 5volts with impunity and it is as well to
rekindle the caution we used to apply (or should have) in
the valve days. For those who want to read up on PCBs try
the writings of Barry Ornitz who is a very knowledgeable
chemical engineer.

Well, I'm not very alarmed:-) PCB's are considered
serious environmental polutants and are toxic, especially
when exposure is chronic. The may be carcinogens but when I
looked this up just a few minutes ago, it does not seem to
be well established, I had thought it was. If you have to
clean it up wear _nitrile_ gloves since the stuff will
penetrate latex. There is certainly no reason to replace
intact PCB filled capacitors if they are not leaking and are
OK electrically.
PCBs began to be used to replace mineral oil in
capacitors and transformers in the 1930s because they are
not inflamible and have better electrical characteristics.
They were sold under many trade names but its possible some
other substances may also have been marketed under those
names. In capacitors and transformers such names as Askarel,
Pyranol (General Electic), Dykanol (Cornel Dublier), and many others.

--
Richard Knoppow
Los Angeles
WB6KBL






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