AR88 enthusiasts in Australia
MoiInAust
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?
Richard Knoppow
Since no one else has responded I got curious and did a little Google
searching. Beside a lot of general stuff on the AR-88, CR-88 and other
variations I found some discussion of the very thing above at:
http://www.vintage-radio.net/forum/showthread.php?t=21717
This may have the answer for you.
BTW, these are very good receivers.
Richard Knoppow
dick...@ix.netcom.com
WB6KBL
Firebottle3
Look here: http://mailman.qth.net/
Click on directory scroll down to RCA join for free or look at the
archives.
Tor
MoiInAust
"Firebottle3" <fireb...@gmail.com> wrote in message
news:dfdc5198-7a96-46b7...@r33g2000yqn.googlegroups.com...
Look here: http://mailman.qth.net/
Thanks Tor and Richard
I was aware of both!
Richard Knoppow
"MoiInAust" <us...@user.com> wrote in message
news:4a4ac361$1...@dnews.tpgi.com.au...
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
dick...@ix.netcom.com
MoiInAust
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" <dick...@ix.netcom.com> wrote in message
news:GoydnRXerJU49NbX...@earthlink.com...
Richard Knoppow
> 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!
I was refering to bathtub electrolytics and electrical
"leakage". If these are oil-filled paper they may well
contain PCBs. I don't know how one disposes of these in Oz
land but the oil is carcinogenic. This is one reason high
voltage transmitting capacitors are hard to find surplus.
Modern plastic caps are far better than the originals.
If you can find suitable terminal boards you can mount them
so that they will not look out of place. Oil filled paper
caps were considered to be high performance and long lived
at the time. Of course, these are probably sixty years old
so that really is long lived. If the impregnant has leaked
out, even partially, the caps have probably changed in
characteristics and should go anyway.
MoiInAust
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" <us...@user.com> wrote in message
news:4a4d...@dnews.tpgi.com.au...
MoiInAust
I was typing my reply when your message arrived. AFAIK there are no
electrolytic caps in an AR88. The bathtubs have groups of 3 of varying (but
the same per tub) capacities, some 0.1, some 0.25 etc.
Even the main smoothing caps are paper. They are 4 mfd.
"Richard Knoppow" <dick...@ix.netcom.com> wrote in message
news:OLedna4SLp_yttDX...@earthlink.com...
Richard Knoppow
> 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.
>
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.
MoiInAust
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" <dick...@ix.netcom.com> wrote in message
news:BIydnTf9gcYR6tDX...@earthlink.com...