Date   
Re: Help restoring a 547 scope

donald collie
 

I use hot, dry, moving air, blowing past all parts of the instrument. I
like the idea of keeping it hot for a full 48 hours, to drive water out of
the cracks. I got impatient once, with a 5245L - when I turned it on the
pilot transformer thet powers the oven, etc, failed.
FWIW........................................................
.................................Don C.
P.S.: I`ve had success with "dual" floor cleaner, but I understand that the
tek note "simple green" was used - this isn`t available where I am, hence
the substitution.

On Fri, Jan 19, 2018 at 2:58 PM, Richard Knoppow <dickburk@...>
wrote:

Regarding Black Beauty caps. There were several series and not all fail
the way the infamous ones do with cracking and breaking cases, however, all
are paper and _all_ paper caps regardless of maker have had limited lives.
Anything old enough to have had BBs in it is old enough to have all its
paper caps replaced regardless of make.
I don't think polyester caps are the best choice and am not sure they
are even made. Polypropylene has the best combination of characteristics
for most applications. They are not expensive and have far better
peformance than the original paper caps had when new. They have excellent
RF characteristics and very low storage factor so can be used in timing
circuits. They are available from all the usual component dealers.
A variation on the cleaning routine is what we used at Hewlett-Packard
long ago:
1, Remove anything that can be water damaged.
2, Rinse off with warm water from a hose.
3, Wash with a solution of mild liquid dishwashing detergent, like Dawn,
in warm water. We sprayed it from a paint sprayer. A brush or brushes can
be used to assist the cleaning.
4, Rinse off using warm water from the hose.
5, Blow out as much residual moisture as possible with compressed air (but
make sure the blower is of the oil-free type).
6, Bake dry in a ventilated oven, I think we had ours set at about 130F.
We baked for a minimum of 48 hours but I liked to go longer.
Stuff comes out looking new. 130F is low enough not to damage anything
but you should still remove plastic parts.
Now, we had a thermostatically controlled electric oven, most people
don't. I think one can do well with an oven made of a couple of large
cardboard boxes with some holes punched to allow circulation and heated
with incandescent light bulbs. Most oven thermometers (from the grocery
store) go down to 130F so you can stick one into the box from the outside
to keep track of the heat.


On 1/18/2018 4:47 PM, donald collie wrote:

Hi Dave,
Sphere Research Corporation have a document available from their website
by
Tek, on how to troubleshoot their `scopes - you might like to read it.
Don`t let this `scope beat you, is the correct attitude, and remember :
most faults are simple - you can see or smell them. Are you sure your
`scope is completely dry? I wash my equipment that I import from eBay in a
bath of hot water, and detergent, rinse in hot pure water, and then dry in
front of a fan heater at about 60 degrees celcius, the hottest you can
hold
your hand on, for at least 6 hours, preferably overnight. I usually clear
the faults before washing, as washing can provoke faults. Expect multiple
faults in a piece of equipment this age.Your `scope may have the imfamous
"Black Beauty" paper capacitors in it - these go leaky, and are best
replaced. They are recognised by their shiny [now shiny - you`ve cleaned
them!] black plastic cases. These are best replaced by polyester types.
You
have a trace! Good! then you have no serious faults. If the `scopes
performance changes with time : Disconnect from the mains, and dry it out
some more. Make a wind tunnel of a cardboard box, and fan heater, so the
whole instrument gets hot, but not too hot. I think you were wise not to
wet the power transformer - I had a transformer fail once after washing.
Next thing i`d ckeck is the various HT`s for correct voltage, using a
meter, and for ripple/noise, using another `scope. This `scope can kill
you
, so be careful. If you have a tube checker, I`d then check all the tubes,
because if the PSU`s aren`t 100%, or you have even 1 doubtful tube, your
pushing it up hill, to find a component fault, so to speak, I`ve just
done
a 475 - it had leaky restorer diodes, and 2 defective transistors, which
fortunately weren`t soldered in, buy rather socketed. With determination,
patience, and the humility to ask those who have walked this road before
you, your `scope will be in factory condition sooner than you think. I
have
a 547 sitting in storage. Perhaps i`ll start on it soon. What goes wrong
with the 547? The group will tell you.
Good luck, and all patience and determination to you!
Cheers!.....................................................
................................................................Don
Collie ZL4GX

<http://www.avg.com/email-signature?utm_medium=email&utm_
source=link&utm_campaign=sig-email&utm_content=webmail>
Virus-free.
www.avg.com
<http://www.avg.com/email-signature?utm_medium=email&utm_
source=link&utm_campaign=sig-email&utm_content=webmail>
<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

On Fri, Jan 19, 2018 at 1:03 PM, Dave Seiter <d.seiter@...> wrote:

Yeah, sometimes you just have to plug it in and go. Waiting for the relay
to kick in can seem like it takes forever!
It is a great scope!
-Dave

--
Richard Knoppow
dickburk@...
WB6KBL




TM500 / 5000 Extenders are a work of art

Rick
 

Dan, I received your extenders. They are beautiful. Tektronix would be jealous! I really apreciate the attention to detail and cool ideas you employed. Since I got a pair I can finally run both AA500 analyzers at the same time to check their calibration. Thank you, Thank you for making these.

Pix here

https://groups.io/g/TekScopes/album?id=15933

Re: Help restoring a 547 scope

Chuck Harris
 

Just a quick note:

There are no systemic bad capacitor failures with the 547. It is
a whole lot newer than tektronix's last use of black beauty
oil/paper capacitors. Its electrolytic caps are very good.

The biggest issues with the 547 are:

1) CRT's HV transformer gets lossy, and causes the HV to
drop after the scope warms up.
2) metal canned germanium transistors grow internal short
circuits... probably tin whiskers.
3) tunnel diodes in the trigger sometimes change threshold
causing the trigger current to need readjusting. In the
extreme, the tunnel diode may need replacing.
4) tubes, yeah, well you knew that. Thankfully, Cathode Interface
problems were pretty well tamed by the time the 547 came along.
5) dirty transistor sockets.

-Chuck Harris

donald collie wrote:

Hi Dave,
Sphere Research Corporation have a document available from their website by
Tek, on how to troubleshoot their `scopes - you might like to read it.
Don`t let this `scope beat you, is the correct attitude, and remember :
most faults are simple - you can see or smell them. Are you sure your
`scope is completely dry? I wash my equipment that I import from eBay in a
bath of hot water, and detergent, rinse in hot pure water, and then dry in
front of a fan heater at about 60 degrees celcius, the hottest you can hold
your hand on, for at least 6 hours, preferably overnight. I usually clear
the faults before washing, as washing can provoke faults. Expect multiple
faults in a piece of equipment this age.Your `scope may have the imfamous
"Black Beauty" paper capacitors in it - these go leaky, and are best
replaced. They are recognised by their shiny [now shiny - you`ve cleaned
them!] black plastic cases. These are best replaced by polyester types. You
have a trace! Good! then you have no serious faults. If the `scopes
performance changes with time : Disconnect from the mains, and dry it out
some more. Make a wind tunnel of a cardboard box, and fan heater, so the
whole instrument gets hot, but not too hot. I think you were wise not to
wet the power transformer - I had a transformer fail once after washing.
Next thing i`d ckeck is the various HT`s for correct voltage, using a
meter, and for ripple/noise, using another `scope. This `scope can kill you
, so be careful. If you have a tube checker, I`d then check all the tubes,
because if the PSU`s aren`t 100%, or you have even 1 doubtful tube, your
pushing it up hill, to find a component fault, so to speak, I`ve just done
a 475 - it had leaky restorer diodes, and 2 defective transistors, which
fortunately weren`t soldered in, buy rather socketed. With determination,
patience, and the humility to ask those who have walked this road before
you, your `scope will be in factory condition sooner than you think. I have
a 547 sitting in storage. Perhaps i`ll start on it soon. What goes wrong
with the 547? The group will tell you.
Good luck, and all patience and determination to you!
Cheers!.....................................................................................................................Don
Collie ZL4GX

<http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail>
Virus-free.
www.avg.com
<http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail>
<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

On Fri, Jan 19, 2018 at 1:03 PM, Dave Seiter <d.seiter@...> wrote:

Yeah, sometimes you just have to plug it in and go. Waiting for the relay
to kick in can seem like it takes forever!
It is a great scope!
-Dave

From: felix_cantor via Groups.Io <felix_cantor=yahoo.com@groups.io>
To: TekScopes@groups.io
Sent: Thursday, January 18, 2018 8:24 AM
Subject: Re: [TekScopes] Help restoring a 547 scope

ok.... ignorance is the mother of all mistakes. It worked!

god! i love this scope.... the trace is so sharp! Amazing.

now i need to fix all the other issues.









Re: Help restoring a 547 scope

Chuck Harris
 

Polyester caps are very much still made... probably the
most popular of the plastic capacitors. Also called by
the trade name mylar.

Some examples are the classic orange drop capacitors.

You may be thinking of polystyrene capacitors, which are
obsolete with the closing of the last factory several years
ago... I'm old, several years usually means decades.

-Chuck Harris

Richard Knoppow wrote:

Regarding Black Beauty caps. There were several series and not all fail the way
the infamous ones do with cracking and breaking cases, however, all are paper and
_all_ paper caps regardless of maker have had limited lives. Anything old enough to
have had BBs in it is old enough to have all its paper caps replaced regardless of make.
I don't think polyester caps are the best choice and am not sure they are even
made. Polypropylene has the best combination of characteristics for most
applications. They are not expensive and have far better peformance than the original
paper caps had when new. They have excellent RF characteristics and very low storage
factor so can be used in timing circuits. They are available from all the usual
component dealers.
A variation on the cleaning routine is what we used at Hewlett-Packard long ago:
1, Remove anything that can be water damaged.
2, Rinse off with warm water from a hose.
3, Wash with a solution of mild liquid dishwashing detergent, like Dawn, in warm
water. We sprayed it from a paint sprayer. A brush or brushes can be used to assist
the cleaning.
4, Rinse off using warm water from the hose.
5, Blow out as much residual moisture as possible with compressed air (but make sure
the blower is of the oil-free type).
6, Bake dry in a ventilated oven, I think we had ours set at about 130F. We baked for
a minimum of 48 hours but I liked to go longer.
Stuff comes out looking new. 130F is low enough not to damage anything but you
should still remove plastic parts.
Now, we had a thermostatically controlled electric oven, most people don't. I
think one can do well with an oven made of a couple of large cardboard boxes with
some holes punched to allow circulation and heated with incandescent light bulbs.
Most oven thermometers (from the grocery store) go down to 130F so you can stick one
into the box from the outside to keep track of the heat.

On 1/18/2018 4:47 PM, donald collie wrote:

Re: TM500 / 5000 Extenders

Rick
 

Dan, I received your extenders. They are beautiful. Tektronix would be jealous! I really apreciate the attention to detail and cool ideas you employed. Since I got a pair I can finally run both AA500 analyzers at the same time to check their calibration. Thank you, Thank you for making these.

Pix here

https://groups.io/g/TekScopes/album?id=15933

Re: Help restoring a 547 scope

felix_cantor@...
 

Many thanks fellas, I really appreciate all you comments.

Luckily i believe the scope survived the wash no problem, I kept her like for an hour fired up and nothing weird happened... she just kept showing off that beautiful trace of hers ;)

Now i think i need to:

-Improve trace stability and display
-Fix Time Base B triggering system (the hardest part I`m afraid)

I don`t see any black beauty cap in her innards. They all seem to be "polysomething", they`re mainly yellow and metallic.

I believe the tubes are ok. This scope is in very good condition, looks like almost new. It seems it belonged to a hospital or something and they didn`t use it much as far as I can see.

HV transformer is behaving till now.

I disassembled the fan, cleaned it and lubricated it... spins like new, if I blow it it spins.
Took out all the knobs and cleaned them thoroughly, also cleaned all the cabinet parts. Looks really pretty right now. She`s is a beaut.

I feel very lucky that she waited all these years, god knows where, for me to get her. I bought her from a guy that pretty much sells garbage... and some pretty nice old electronic equipment (I also got an HP 8640B signal generator, very nice too!... and a few other things).

Today I will continue cleaning transistor legs and sockets, and see if anything improves.

Thanks and have a nice day.

Felix Cantor.

Tek 7633 5volt ripple

Brendan
 

Picked up a 7633. It has no sweep just a dot. After checking the 15v,130v and 5v power i see there is massive ripple on the 5 volt supply. Others seem fine. The 453 is @ 5v/div ,the picture is fuzzy. I plan on recapping this beast but I would like to solve the trace issue prior. If only the 5v rail is showing ripple I'm ASSuming that the powers supply caps are not the issue.

https://groups.io/g/TekScopes/photo/15940/0?p=Name,,,20,1,0,0

Re: Tek 7633 5volt ripple

 

Always fix the power supplies first. Otherwise you are just wasting your time.

----- Original Message -----
From: "lop pol via Groups.Io" <the_infinite_penguin=yahoo.com@groups.io>
To: <TekScopes@groups.io>
Sent: Friday, January 19, 2018 10:27 AM
Subject: [TekScopes] Tek 7633 5volt ripple


Picked up a 7633. It has no sweep just a dot. After checking the 15v,130v and 5v power i see there is massive ripple on the 5 volt supply. Others seem fine. The 453 is @ 5v/div ,the picture is fuzzy. I plan on recapping this beast but I would like to solve the trace issue prior. If only the 5v rail is showing ripple I'm ASSuming that the powers supply caps are not the issue.

https://groups.io/g/TekScopes/photo/15940/0?p=Name,,,20,1,0,0

Re: Transistor Cross Reference - Now N101 transistor info

Jim Strohm
 

Dave,

Some manufacturers used to mark their dies (I assume you mean the plastic
overmolds) for transistors. Motorola was famous for putting their "Circle
M" brand on their TO-92 transistors back in the last century. This was
before semiconductor counterfeiting became big business, though why
somebody would counterfeit a 2N3904 is beyond me.

I wish they'd added an embossing design for TO-3 transistors -- I think I
would have paid a dollar extra per 2N3055 (or better) to have an embossed
Circle M to guarantee authenticity ... but if they did that, it'd mess up
the screen-printed or roller-printed part number and date code.

Nowadays it's cheap enough to laser-etch a logo, but ON Semi (the MOTO
spin-off for commodity semiconductors) has not seen fit to do this on their
parts, and regardless of that, the semi counterfeiters in China now have
deep enough pockets to buy laser etching equipment.

So ... I guess your best source for scarce or obsolete transistors may
still be the original source that the Chinese counterfeiters use -- remove
them from the original equipment and clean them up. Past that? We could
try to ascertain the original specs of the unobtainium parts, and locate
the closest-fit modern substitute that's available through first-tier disti
like Digi-key and Mouser.

Oh yeah, and there's this kid in California who's built a semiconductor fab
in his garage, and can reproduce semi dice in similar process technologies
to what was being done in the 70s and 80s. He might be able to make stuff
for us, if we seed him with some good surplus wire-bonding and overmold
equipment.

In fact, my company may want to approach him with a marketing offer and
some seed equipment...

73
Jim N6OTQ

Re: Tek 475 HV multiplier replacement

Dieter <ditt1@...>
 

Thank you for your replies.
I have replaced the multiplier.
The connector of the old HV-cable I cut off, drilled out the rest and soldered the new cable.
The openings were closed with a glue gun.
Works perfect.

Re: Help restoring a 547 scope

John Griessen
 

On 01/18/2018 11:26 PM, Chuck Harris wrote:
You may be thinking of polystyrene capacitors, which are
obsolete with the closing of the last factory several years
ago...
So, are the GR decade cap boxes, (type 1424A), with those in danger of failing? Are they performance obsolete,
or cost obsolete?

Re: Help restoring a 547 scope

Geoffrey Thomas
 

Polystyrene capacitors are still in production, are you referring to a specific type?
Sorry, haven't read the whole thread.

On 19/01/2018 16:40, John Griessen wrote:
On 01/18/2018 11:26 PM, Chuck Harris wrote:
You may be thinking of polystyrene capacitors, which are
obsolete with the closing of the last factory several years
ago...
So, are the GR decade cap boxes, (type 1424A), with those in danger of failing?  Are they performance obsolete,
or cost obsolete?

Re: Help restoring a 547 scope

Chuck Harris
 

They are obsolete because of the extremely careful
handling they require. Note their very thin leads.
This is to prevent them from melting during normal
soldering activity.

Once installed, polystyrene caps should last forever.

-Chuck Harris

John Griessen wrote:

On 01/18/2018 11:26 PM, Chuck Harris wrote:
You may be thinking of polystyrene capacitors, which are
obsolete with the closing of the last factory several years
ago...
So, are the GR decade cap boxes, (type 1424A), with those in danger of failing? Are
they performance obsolete,
or cost obsolete?



Re: Help restoring a 547 scope

Chuck Harris
 

I remember a trade journal announcement, that the last
factory went off line, about 10-20 years ago. It seemed
foolish to me at the time, as the Q of polystyrene caps
isn't easy to match with other varieties.

I would not be at all surprised to find that someone
restarted production, though I am not sure how they
would currently be used. Surface mount is out of the
question due to high soldering temperatures, and very
low styrene melting point.

-Chuck Harris

Geoffrey Thomas wrote:

Polystyrene capacitors are still in production, are you referring to a specific type?
Sorry, haven't read the whole thread.


On 19/01/2018 16:40, John Griessen wrote:
On 01/18/2018 11:26 PM, Chuck Harris wrote:
You may be thinking of polystyrene capacitors, which are
obsolete with the closing of the last factory several years
ago...
So, are the GR decade cap boxes, (type 1424A), with those in danger of failing?
Are they performance obsolete,
or cost obsolete?

Re: Transistor Cross Reference - Now N101 transistor info

Dave Wise
 

Interesting information, Jim, but Chuck is referring to the metallization pattern on the semiconductor wafer itself. He's expecting that when I cut the top off the can and look inside, I'll see a microscopic logo. If this is a planar transistor with "2N1304" on the can, there might indeed be one, but not if it's actual 1960's alloy junction construction.

Dave Wsie
________________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Jim Strohm <jim.strohm@...>
Sent: Friday, January 19, 2018 7:31 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Transistor Cross Reference - Now N101 transistor info

Dave,

Some manufacturers used to mark their dies (I assume you mean the plastic
overmolds) for transistors. Motorola was famous for putting their "Circle
M" brand on their TO-92 transistors back in the last century. This was
before semiconductor counterfeiting became big business, though why
somebody would counterfeit a 2N3904 is beyond me.

I wish they'd added an embossing design for TO-3 transistors -- I think I
would have paid a dollar extra per 2N3055 (or better) to have an embossed
Circle M to guarantee authenticity ... but if they did that, it'd mess up
the screen-printed or roller-printed part number and date code.

Nowadays it's cheap enough to laser-etch a logo, but ON Semi (the MOTO
spin-off for commodity semiconductors) has not seen fit to do this on their
parts, and regardless of that, the semi counterfeiters in China now have
deep enough pockets to buy laser etching equipment.

So ... I guess your best source for scarce or obsolete transistors may
still be the original source that the Chinese counterfeiters use -- remove
them from the original equipment and clean them up. Past that? We could
try to ascertain the original specs of the unobtainium parts, and locate
the closest-fit modern substitute that's available through first-tier disti
like Digi-key and Mouser.

Oh yeah, and there's this kid in California who's built a semiconductor fab
in his garage, and can reproduce semi dice in similar process technologies
to what was being done in the 70s and 80s. He might be able to make stuff
for us, if we seed him with some good surplus wire-bonding and overmold
equipment.

In fact, my company may want to approach him with a marketing offer and
some seed equipment...

73
Jim N6OTQ

Re: Help restoring a 547 scope

Geoffrey Thomas
 

LCR components, Tredegar, still manufacture them. In fact, they never stopped.

http://www.lcrcapacitors.co.uk/polystyrene/fsc-polystyrene-2/

Geoff.

On 19/01/2018 17:15, Chuck Harris wrote:
I remember a trade journal announcement, that the last
factory went off line, about 10-20 years ago. It seemed
foolish to me at the time, as the Q of polystyrene caps
isn't easy to match with other varieties.
I would not be at all surprised to find that someone
restarted production, though I am not sure how they
would currently be used. Surface mount is out of the
question due to high soldering temperatures, and very
low styrene melting point.
-Chuck Harris
Geoffrey Thomas wrote:
Polystyrene capacitors are still in production, are you referring to a specific type?
Sorry, haven't read the whole thread.


On 19/01/2018 16:40, John Griessen wrote:
On 01/18/2018 11:26 PM, Chuck Harris wrote:
You may be thinking of polystyrene capacitors, which are
obsolete with the closing of the last factory several years
ago...
So, are the GR decade cap boxes, (type 1424A), with those in danger of failing?
Are they performance obsolete,
or cost obsolete?

Re: Help restoring a 547 scope

Dave Wise
 

I thought that polypropylene is the accepted substitute. It has lower D than the mica reference cap in my GR 1656 bridge.

Dave Wise
________________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Chuck Harris <cfharris@...>
Sent: Friday, January 19, 2018 9:15 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Help restoring a 547 scope

I remember a trade journal announcement, that the last
factory went off line, about 10-20 years ago. It seemed
foolish to me at the time, as the Q of polystyrene caps
isn't easy to match with other varieties.

I would not be at all surprised to find that someone
restarted production, though I am not sure how they
would currently be used. Surface mount is out of the
question due to high soldering temperatures, and very
low styrene melting point.

-Chuck Harris

Geoffrey Thomas wrote:
Polystyrene capacitors are still in production, are you referring to a specific type?

Re: Help restoring a 547 scope

Chuck Harris
 

When I search Mouser for polystyrene caps, they have only one
manufacturer, Xicon, the parts are not ROHS, and they list
only 22 different parts in total. Sounds a bit like NOS parts
to me.

When I duckduckgo search on polystyrene caps, the theme that
keeps coming up is they are wonderful for a lot of applications,
won't be made in SMD form, but are very difficulty to source.

The second theme that keeps coming up, is "oh, you mean film
capacitors", which I do not.

I know what I saw in the trade journal way back when, but clearly
there is still some stock available.

After all, the Chinese find value in welding new leads on recycled
transistors, IC's and capacitors.

-Chuck Harris

Geoffrey Thomas wrote:

LCR components, Tredegar, still manufacture them. In fact, they never stopped.

http://www.lcrcapacitors.co.uk/polystyrene/fsc-polystyrene-2/

Geoff.

On 19/01/2018 17:15, Chuck Harris wrote:
I remember a trade journal announcement, that the last
factory went off line, about 10-20 years ago. It seemed
foolish to me at the time, as the Q of polystyrene caps
isn't easy to match with other varieties.

I would not be at all surprised to find that someone
restarted production, though I am not sure how they
would currently be used. Surface mount is out of the
question due to high soldering temperatures, and very
low styrene melting point.

-Chuck Harris

Re: Help restoring a 547 scope

Chuck Harris
 

They list them, but do we know they are actually being
made? I know that when a run gets started, you have to
make a gadzillion to make it worth having set up the
machines.

I could see a million units being stored in a phone booth
sized area of a warehouse.

Note, that these are all through hole, and kind of large.
I wonder what applications in today's electronics actually
uses them?

-Chuck Harris

Geoffrey Thomas wrote:

LCR components, Tredegar, still manufacture them. In fact, they never stopped.

http://www.lcrcapacitors.co.uk/polystyrene/fsc-polystyrene-2/

Geoff.

On 19/01/2018 17:15, Chuck Harris wrote:
I remember a trade journal announcement, that the last
factory went off line, about 10-20 years ago. It seemed
foolish to me at the time, as the Q of polystyrene caps
isn't easy to match with other varieties.

I would not be at all surprised to find that someone
restarted production, though I am not sure how they
would currently be used. Surface mount is out of the
question due to high soldering temperatures, and very
low styrene melting point.

-Chuck Harris

Re: Help restoring a 547 scope

Geoffrey Thomas
 

On 19/01/2018 17:51, Chuck Harris wrote:
They list them, but do we know they are actually being
made? I know that when a run gets started, you have to
make a gadzillion to make it worth having set up the
machines.
I could see a million units being stored in a phone booth
sized area of a warehouse.
Note, that these are all through hole, and kind of large.
I wonder what applications in today's electronics actually
uses them?
-Chuck Harris
Geoffrey Thomas wrote:
LCR components, Tredegar, still manufacture them. In fact, they never stopped.

http://www.lcrcapacitors.co.uk/polystyrene/fsc-polystyrene-2/

Geoff.

On 19/01/2018 17:15, Chuck Harris wrote:
I remember a trade journal announcement, that the last
factory went off line, about 10-20 years ago. It seemed
foolish to me at the time, as the Q of polystyrene caps
isn't easy to match with other varieties.

I would not be at all surprised to find that someone
restarted production, though I am not sure how they
would currently be used. Surface mount is out of the
question due to high soldering temperatures, and very
low styrene melting point.

-Chuck Harris