"Michael A. Terrell" wrote in message
...

I am restoring a TS-382 Audio signal generator that is built with
all
bathtub cabs, and every one of them is bad. They were made with the
same
high acid paper that wax and molded capacitors were made with, they
are
just sealed in transformer oil. I am in the process of unsoldering the
cans and replacing the caps inside with metal film capacitors I have
to
use a torch to heat the case and cover. There is a small vent hole
that
is soldered shut. You have to find it and remove the solder first, or
it
may blow hot solder on you when remove solder melts around the edge of
the cover. Then I use a curved dental pick to lift the cover off while
carefully heating the cover with a torch. I use a small drill press
vice
with smooth jaws to hold the can, and set it on a sheet of steel. (An
old desktop PC case is good, because it has an open airspace under
it.)

Steel bath tub caps have been pretty reliable for me. Certainly more
reliable than paper or electolytic caps. I've got the chassis out of my
S-36, and I'll check those steel caps carefully.


When I started this I dug through my collection of NOS bathtubs,
and
most of them have high leakage as well. I did find one company who
still makes new bathtub, and other oil filled caps, but I couldn't
spend
several hundred dollars for new caps for one project.
--
21 days!


Michael A. Terrell
Central Florida

I only have a few NOS steel caps in my collection. I checked them a
couple of years ago, and they were good.

Anyway, oil filled steel caps were more reliable than paper caps and
electrolytics in the mid 50s and were the usual choice with cost is no
object equipment.

Frank Dresser

In article ,
"Frank Dresser" writes:

Anyway, oil filled steel caps were more reliable than paper caps and
electrolytics in the mid 50s and were the usual choice with cost is no
object equipment.

When I got my Collins R-388 (51J3), the AVC was bad. I was surprised when I
traced it to a very leaky steel bathtub cap -- I thought those mil-spec babies
never went bad. I left the cap in place a wired a replacement on top of it
(not beautiful, but easily "restored" to "original").

I still wouldn't go thru a radio and just replace every metal bathtub cap, the
way you would the wax firecrackers or Black Uglies.

If I somehow found an SX-88, I would insist on using it, often -- so would
recap it and enjoy. My widow will still get her $10 for it either way. --Mike
K.

Oscar loves trash, but hates Spam! Delete him to reply to me.

"Mike Knudsen" wrote in message
...
I was surprised when I
traced it to a very leaky steel bathtub cap -- I thought those mil-spec
babies
never went bad. I left the cap in place a wired a replacement on top of
it
(not beautiful, but easily "restored" to "original").

I had the same experience when restoring my 2nd Scott 800B6. Someone alerted
me during that project that some bathtubs are in fact paper caps, not
oil-filled, and you can't really tell the difference by staring at them. I
tested them and sure enough, they were leaky as heck. I wired replacements
around the original bathtubs, as Mike describes. One of these days, I should
go back through my 1st 800B6 and check the bathtubs that I left untouched,
on the assumption that they were "just fine."

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

In article k.net, "Phil
Nelson" writes:

I wired replacements
around the original bathtubs, as Mike describes. One of these days, I should
go back through my 1st 800B6 and check the bathtubs that I left untouched,
on the assumption that they were "just fine."

Glad someone else agrees with my "bathtub" experience (well, maybe not glad
that someone else had to replace one too).

I'm starting to wonder if there's such a thing as a cap that can always be
*assumed* to be good (mica, vacuum, etc.). Well, maybe assumed good till the
evidence points right to it (smoking resistor, not gun :-) --Mike K.

Oscar loves trash, but hates Spam! Delete him to reply to me.