I have a very old carrier condenser. I need a replacement fan motor. The current motor is a 5kcp39bg GE unit with the following specs:

RPM = 1100 HP= 1/10 HZ = 60 u = 208-230. A= .75 Rot Cap = 5.00/370.

What I am finding is no one has a direct replacement. Several mention using another horsepower motor but then the amps are different.

What would be "safe" to use if having to go up in horsepower/amps?

Also, my motor mounts to the top of the condenser lid with acorn nuts. Do any of the above numbers show the fit or proper spacing of the studs?

Thanks for any help you can provide.

On Tue, 11 Aug 2015 07:55:36 -0700 (PDT), stryped
wrote:

I have a very old carrier condenser. I need a replacement fan motor. The current motor is a 5kcp39bg GE unit with the following specs:

RPM = 1100 HP= 1/10 HZ = 60 u = 208-230. A= .75 Rot Cap = 5.00/370.

What I am finding is no one has a direct replacement. Several mention using another horsepower motor but then the amps are different.

What would be "safe" to use if having to go up in horsepower/amps?

Also, my motor mounts to the top of the condenser lid with acorn nuts. Do any of the above numbers show the fit or proper spacing of the studs?

Thanks for any help you can provide.
Many years ago I ran a vacuum cleaner repair shop. At that time I knew
of several motor rewinding shops that repaired all small electric
motors.

fired this volley in
news
At that time I knew
of several motor rewinding shops that repaired all small electric
motors.

And they've all gone by the wayside. Nobody actually "repairs" anything
at the component-level anymore. Everyone is now, what in the 60s in the
TV repair business, what we referred to as "tube caddies". They just
replace (expensive) components as a full assembly. No actual 'repairs'.

Our (best) local AC company can't even find a technician who can properly
find and repair a minor slow-leak of refrigerant on an AC unit. "Oh...
you'll need a new condensor unit" is all they can offer.

I can still find and fix them, and I'm not an AC guy. Why can't they?

Why? Because now labor is more expensive than hardware. It's just the
way things have evolved.

Lloyd

On Tuesday, August 11, 2015 at 7:55:40 AM UTC-7, stryped wrote:
I have a very old carrier condenser. I need a replacement fan motor. The current motor is a 5kcp39bg GE unit with the following specs:

RPM = 1100 HP= 1/10 HZ = 60 u = 208-230. A= .75 Rot Cap = 5.00/370.

What I am finding is no one has a direct replacement. Several mention using another horsepower motor but then the amps are different.

What would be "safe" to use if having to go up in horsepower/amps?

The starting current might go up (so it behooves you to check the ratings of whatever
relay or contactor drives this motor), but operating current will be about
the same (because you aren't changing the mechanical load). So, substitute away!

1100 RPM is kinda oddball, but a web search finds the part; Amazon and other
suppliers will sell you an identical replacement part, it seems.

On Tuesday, August 11, 2015 at 10:55:40 AM UTC-4, stryped wrote:
I have a very old carrier condenser. I need a replacement fan motor. The current motor is a 5kcp39bg GE unit with the following specs:

RPM = 1100 HP= 1/10 HZ = 60 u = 208-230. A= .75 Rot Cap = 5.00/370.

What I am finding is no one has a direct replacement. Several mention using another horsepower motor but then the amps are different.

What would be "safe" to use if having to go up in horsepower/amps?

Also, my motor mounts to the top of the condenser lid with acorn nuts. Do any of the above numbers show the fit or proper spacing of the studs?

Thanks for any help you can provide.

http://www.southernwinding.com/

Try those folks. I've had very good service from them over the years with small motor rewinds.

whit3rd fired this volley in
:

1100 RPM is kinda oddball, but a web search finds the part; Amazon and
other suppliers will sell you an identical replacement part, it seems.


Not to Stryped. He doesn't LOOK for parts before he asks here to get
help finding the parts he never looked for... Heck, he doesn't look for
_any_ information before he asks here.

And with deference to you (few) guys who actually know what you're doing,
this is the LAST place anyone should ask for good, sound mechanical
advice!


Lloyd

On Tue, 11 Aug 2015 16:32:20 -0700 (PDT), Garrett Fulton
wrote:

On Tuesday, August 11, 2015 at 10:55:40 AM UTC-4, stryped wrote:
I have a very old carrier condenser. I need a replacement fan motor. The current motor is a 5kcp39bg GE unit with the following specs:

RPM = 1100 HP= 1/10 HZ = 60 u = 208-230. A= .75 Rot Cap = 5.00/370.

What I am finding is no one has a direct replacement. Several mention using another horsepower motor but then the amps are different.

What would be "safe" to use if having to go up in horsepower/amps?

Also, my motor mounts to the top of the condenser lid with acorn nuts. Do any of the above numbers show the fit or proper spacing of the studs?

Thanks for any help you can provide.

http://www.southernwinding.com/

Try those folks. I've had very good service from them over the years with small motor rewinds.

Someone made the comment not long ago that there were no motor rebuild
shops left anymore. While I cant speak for Canukistan, every area
larger than about 50k people that Ive had to do work in and
around..has someone who rebuilds electric motors. Bakersfield..which
is really not a large city by any means..has at least 3 rewind shops.
I have at least 15 business cards from shops in So. California..and
its not..not really a hotbed of manufacturing anymore. Yeah..a bunch
of other such shops have gone tits up..but there are still more than
enough to handle business.

Just keep in mind that at least in this area (So Cal) ...motor
rebuilding will cost 2/3rds the price of a replacement motor. So if
you have a cheap crappy motor..it may not be appropriate to have it
rebuilt..but to replace it with a more modern more efficent motor.

Call your "local" motor rebuild shop..because everyone Ive ever dealt
with, has motors that were rebuilt but never picked up and you can get
them cheaply ..often times for less than half of what a replacement
will cost.

Btw...when an American shop repairs an import or poor quality
motor..its generally in better than new condition when you get it
back.

Something to use in the future if you need to purchase a motor.

Gunner

On 8/11/2015 2:45 PM, Lloyd E. Sponenburgh wrote:
fired this volley in
news
At that time I knew
of several motor rewinding shops that repaired all small electric
motors.

And they've all gone by the wayside. Nobody actually "repairs" anything
at the component-level anymore. Everyone is now, what in the 60s in the
TV repair business, what we referred to as "tube caddies". They just
replace (expensive) components as a full assembly. No actual 'repairs'.

Our (best) local AC company can't even find a technician who can properly
find and repair a minor slow-leak of refrigerant on an AC unit. "Oh...
you'll need a new condensor unit" is all they can offer.

I can still find and fix them, and I'm not an AC guy. Why can't they?

Why? Because now labor is more expensive than hardware. It's just the
way things have evolved.

Lloyd


Yep! I once had a AC company do a free estimate on my condenser pump
that wouldn't start. I told him I suspected the cap and asked him how
much to just replace the cap and he had a spare on his truck. He wanted
$327 with no guarantee. I waited until Monday and got one from Grainger
for $27. What refrigerant are you using in the leaker?

Tom Gardner fired this volley in news:mqohd4$la2$1
@speranza.aioe.org:

What refrigerant are you using in the leaker?



R22, and it leaks about a pound or two a year, which may be below the
threshold of my equipment (though the specs say it should pick it up).

Last time I pumped it down and re-charged it, I replaced both Schrader
valve cores, so it's not _likely_ them (but could be, of course).

More likely is a tiny spec of not-well-done soldering somewhere.

Oh, well... I've got about 28lb of pre-ban R22 still in stock, so if I
don't have to pull it down again, technically I've got 14 years worth!
G (yeah... I know...like THAT will happen! G)

Lloyd

On Sat, 15 Aug 2015 19:18:52 -0400, Tom Gardner
wrote:

On 8/11/2015 2:45 PM, Lloyd E. Sponenburgh wrote:
fired this volley in
news
At that time I knew
of several motor rewinding shops that repaired all small electric
motors.

And they've all gone by the wayside. Nobody actually "repairs" anything
at the component-level anymore. Everyone is now, what in the 60s in the
TV repair business, what we referred to as "tube caddies". They just
replace (expensive) components as a full assembly. No actual 'repairs'.

Our (best) local AC company can't even find a technician who can properly
find and repair a minor slow-leak of refrigerant on an AC unit. "Oh...
you'll need a new condensor unit" is all they can offer.

I can still find and fix them, and I'm not an AC guy. Why can't they?

Why? Because now labor is more expensive than hardware. It's just the
way things have evolved.

Lloyd


Yep! I once had a AC company do a free estimate on my condenser pump
that wouldn't start. I told him I suspected the cap and asked him how
much to just replace the cap and he had a spare on his truck. He wanted
$327 with no guarantee.

I'd have called his boss right then and there to complain. That's
outright rape. It may have done no good, but if you successfully
weeded just one bad apple out of his company, the boss might have done
the job for you for free. It's a freakin' 1/2 hour job and $10 part!
(If the boss was him, or boss was OK with it, tell everyone you know)


1) shut off thermostat & throw the switch on the cutout.
2) pop the sheetmetal cover off.
3) map out and disconnect the cap leads
4) short the cap for safety
5) loosen 1 screw holding cap
6) r&r cap
7) replace cap leads
8) reinstall sheetmetal cover
9) throw the switch
10) go inside for cool air.


I waited until Monday and got one from Grainger
for $27. What refrigerant are you using in the leaker?

I happened to be in my Chiro's office when the HVAC guy came around. I
asked him if he had a cap for my unit and he brought the $15 invoice
and the cap in from the truck 3 minutes later.

--
The beauty of the 2nd Amendment is that it will not be needed
until they try to take it. --Thomas Jefferson

On 08/15/2015 06:18 PM, Tom Gardner wrote:
Yep! I once had a AC company do a free estimate on my condenser pump
that wouldn't start. I told him I suspected the cap and asked him how
much to just replace the cap and he had a spare on his truck. He wanted
$327 with no guarantee. I waited until Monday and got one from Grainger
for $27.

Even worse, during an annual maintenance visit I was told that my
capacitor was getting weak (True, it was.). I asked how much for a
new one and was told $50 for the part and, get this, $70 labor to
install it. The guy had the old part out of the machine to measure
it. No charge to put the old cap back in the machine, but $70 to
do the same thing with a new one. I told him, "No, thanks," and
found a seller on eBay that would send me two (2) exact replacements
for a total of $15.60 with free shipping. The first of those has
been in use for 2 Summers now, with no sign of a problem.

--
Bob Nichols AT comcast.net I am "RNichols42"

I have three of the new room types - outdoor unit and indoor unit.
Two lost refrigerant for a year. Call after call they refilled.
I insisted they put in a can of trace colorant and finally they did.

My dear wife then when they ran out again, called a company that worked
on the house not on the office. He came out and said he wasn't with
that company but would look. Both units had hoses with loose
connections. The other company thought they tightened the joints and
tried flame and bubbles to locate the leaks. Trace did.

The installing company has yet to call to see if the trace did anything.

The house guy working on the house - put in two cans of material that
reduced the acid in the lines. We have high water in the air here.

Martin

On 8/15/2015 6:25 PM, Lloyd E. Sponenburgh wrote:
Tom Gardner fired this volley in news:mqohd4$la2$1
@speranza.aioe.org:

What refrigerant are you using in the leaker?



R22, and it leaks about a pound or two a year, which may be below the
threshold of my equipment (though the specs say it should pick it up).

Last time I pumped it down and re-charged it, I replaced both Schrader
valve cores, so it's not _likely_ them (but could be, of course).

More likely is a tiny spec of not-well-done soldering somewhere.

Oh, well... I've got about 28lb of pre-ban R22 still in stock, so if I
don't have to pull it down again, technically I've got 14 years worth!
G (yeah... I know...like THAT will happen! G)

Lloyd

On 8/15/2015 7:25 PM, Lloyd E. Sponenburgh wrote:
Tom Gardner fired this volley in news:mqohd4$la2$1
@speranza.aioe.org:

What refrigerant are you using in the leaker?



R22, and it leaks about a pound or two a year, which may be below the
threshold of my equipment (though the specs say it should pick it up).

Last time I pumped it down and re-charged it, I replaced both Schrader
valve cores, so it's not _likely_ them (but could be, of course).

More likely is a tiny spec of not-well-done soldering somewhere.

Oh, well... I've got about 28lb of pre-ban R22 still in stock, so if I
don't have to pull it down again, technically I've got 14 years worth!
G (yeah... I know...like THAT will happen! G)

Lloyd


I was going to mention R-22A which I got a cylinder for $130 delivered.
I'm running a mix now because mine loses about 1.5 lbs/yr and after 3
years I have no complaints and it runs lower pressure now.

On 8/16/2015 9:33 AM, Robert Nichols wrote:
On 08/15/2015 06:18 PM, Tom Gardner wrote:
Yep! I once had a AC company do a free estimate on my condenser pump
that wouldn't start. I told him I suspected the cap and asked him how
much to just replace the cap and he had a spare on his truck. He wanted
$327 with no guarantee. I waited until Monday and got one from Grainger
for $27.

Even worse, during an annual maintenance visit I was told that my
capacitor was getting weak (True, it was.). I asked how much for a
new one and was told $50 for the part and, get this, $70 labor to
install it. The guy had the old part out of the machine to measure
it. No charge to put the old cap back in the machine, but $70 to
do the same thing with a new one. I told him, "No, thanks," and
found a seller on eBay that would send me two (2) exact replacements
for a total of $15.60 with free shipping. The first of those has
been in use for 2 Summers now, with no sign of a problem.


I have to replace my dual cap every 2 years, why don't they last?

Tom Gardner fired this volley in news:mqrt5r$90r$1
@speranza.aioe.org:

I have to replace my dual cap every 2 years, why don't they last?

I used to think it was "poor quality work", but I believe now that it's a
combination of the impact of "controlled substances" (like PCBs) and
deliberate planned-life designs.

Keep in mind that such caps are NOT considered a "user replacable part",
so if the electrical components industry can convince the end-user
"that's just the life of the part", then both the parts makers and the
local service companies benefit by getting more work.

When you add to that scheme the fact that the _right_ materials for
building a good (and compact) capacitor are mostly all illegal now, it
all seems to make sense.

And yes, they could still make good caps for military and high-end
commercial gear, but they usually MUCH larger, and might not fit in
equipment designed for the smaller form-factor parts. (plus the
exhorbitant prices)

LLoyd

On 08/17/2015 12:58 AM, Tom Gardner wrote:
On 8/16/2015 9:33 AM, Robert Nichols wrote:
On 08/15/2015 06:18 PM, Tom Gardner wrote:
Yep! I once had a AC company do a free estimate on my condenser pump
that wouldn't start. I told him I suspected the cap and asked him how
much to just replace the cap and he had a spare on his truck. He wanted
$327 with no guarantee. I waited until Monday and got one from Grainger
for $27.

Even worse, during an annual maintenance visit I was told that my
capacitor was getting weak (True, it was.). I asked how much for a
new one and was told $50 for the part and, get this, $70 labor to
install it. The guy had the old part out of the machine to measure
it. No charge to put the old cap back in the machine, but $70 to
do the same thing with a new one. I told him, "No, thanks," and
found a seller on eBay that would send me two (2) exact replacements
for a total of $15.60 with free shipping. The first of those has
been in use for 2 Summers now, with no sign of a problem.


I have to replace my dual cap every 2 years, why don't they last?

They're pushed within an inch of their lives on voltage rating
(Measure the voltage across one some time -- you'll be surprised.),
and baked in the sun on hot, Summer days. They would last a lot
longer in a more hospitable environment.

--
Bob Nichols AT comcast.net I am "RNichols42"

On Sat, 15 Aug 2015 19:27:12 -0700, Larry Jaques
wrote:



1) shut off thermostat & throw the switch on the cutout.
2) pop the sheetmetal cover off.
3) map out and disconnect the cap leads
4) short the cap for safety
5) loosen 1 screw holding cap
6) r&r cap
7) replace cap leads
8) reinstall sheetmetal cover
9) throw the switch
10) go inside for cool air.

Just did that with the outdoor fan motor.. about $13 from the local
wholesale supplier for a dual 5uF/40uF 440VAC capacitor, pop it in and
ahhh cool air.

The fan motor was getting really hot, but not hot enough to destroy
it.

I hate to think what it would have cost to pay some dude to replace
the fan motor, probably $1K+ for not much more work. Maybe the price
goes up with house size and brand of A/C unit.


--sp

--
Best regards,
Spehro Pefhany
Amazon link for AoE 3rd Edition: http://tinyurl.com/ntrpwu8
Microchip link for 2015 Masters in Phoenix: http://tinyurl.com/l7g2k48

On Mon, 17 Aug 2015 01:58:18 -0400, Tom Gardner
wrote:



I have to replace my dual cap every 2 years, why don't they last?

I seem to have to replace mine every 20 years (i.e. once). But the
replacement is significantly smaller (had to modify the clamp). That
does not bode well.

Actually if this is not just a rhetorical question- the capacitors
when used within ratings do not really have a failure mode. They are
plastic film capacitors with some gunk to prevent moisture from
screwing things up. Unlike electrolytic caps that do have a definite
lifetime.

I suspect that what happens is that lighting and other transients
causes breakdown that causes a self-healing (because the short blows
away) short in the aluminized film. The value of the cap drops with
each surge until it's no longer high enough to support the motor
operation. The 5uF (?) one in my furnace draft inducer fan was down to
something like 1uF when it took out the fan motor (ouch$$$).

They've just pushed the thickness of the film down so far to save
money (and the volts/mil does not change) so the caps are more
susceptible to overvoltage spikes.

Just a guess.


--sp

--
Best regards,
Spehro Pefhany
Amazon link for AoE 3rd Edition: http://tinyurl.com/ntrpwu8
Microchip link for 2015 Masters in Phoenix: http://tinyurl.com/l7g2k48

Spehro Pefhany fired this volley in
:

I suspect that what happens is that lighting and other transients
causes breakdown that causes a self-healing (because the short blows
away) short in the aluminized film. The value of the cap drops with
each surge until it's no longer high enough to support the motor
operation. The 5uF (?) one in my furnace draft inducer fan was down to
something like 1uF when it took out the fan motor (ouch$$$).

They've just pushed the thickness of the film down so far to save
money (and the volts/mil does not change) so the caps are more
susceptible to overvoltage spikes.


No, being an 'empirical chemist' one of my interests is in how polymers
act with time. Storage issues with pyrotechnic compositions containing
them is the matter at hand.

Most of the polymers used for the dielectric film undergo slow
degradation due to oxygen, chlorine, or sometimes even nitrogen in
contact with them.

They also can react (most slowly) to strong electrical fields across
them.

In any case, they slowly break down into compounds which are not
particularly good insulators, lowering the capacity, and eventually
allowing shorts to occur at the rated voltage.

It's not unexpected -- they make them to the BAREST minimums necessary to
manage the applied voltage, as it is.

Once, caps were 'over-rated'... no longer. Otherwise, the motor-start
capacitor guys would lose that 'replacement market'!

Lloyd

On Mon, 17 Aug 2015 06:09:53 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Tom Gardner fired this volley in news:mqrt5r$90r$1
:

I have to replace my dual cap every 2 years, why don't they last?

Perhaps you might try going with another brand, and doublecheck with
the HVAC mfgr that the cap you're replacing is the correct value for
the unit you have.


I used to think it was "poor quality work", but I believe now that it's a
combination of the impact of "controlled substances" (like PCBs) and
deliberate planned-life designs.

Hmmm...


Keep in mind that such caps are NOT considered a "user replacable part",
so if the electrical components industry can convince the end-user
"that's just the life of the part", then both the parts makers and the
local service companies benefit by getting more work.

Rapists.


When you add to that scheme the fact that the _right_ materials for
building a good (and compact) capacitor are mostly all illegal now, it
all seems to make sense.

And yes, they could still make good caps for military and high-end
commercial gear, but they usually MUCH larger, and might not fit in
equipment designed for the smaller form-factor parts. (plus the
exhorbitant prices)

Let's see, if a USAF toilet seat costs...

--
The beauty of the 2nd Amendment is that it will not be needed
until they try to take it. --Thomas Jefferson

On Mon, 17 Aug 2015 06:09:53 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Tom Gardner fired this volley in news:mqrt5r$90r$1
:

I have to replace my dual cap every 2 years, why don't they last?

I used to think it was "poor quality work", but I believe now that it's a
combination of the impact of "controlled substances" (like PCBs) and
deliberate planned-life designs.

Keep in mind that such caps are NOT considered a "user replacable part",
so if the electrical components industry can convince the end-user
"that's just the life of the part", then both the parts makers and the
local service companies benefit by getting more work.

When you add to that scheme the fact that the _right_ materials for
building a good (and compact) capacitor are mostly all illegal now, it
all seems to make sense.

And yes, they could still make good caps for military and high-end
commercial gear, but they usually MUCH larger, and might not fit in
equipment designed for the smaller form-factor parts. (plus the
exhorbitant prices)

LLoyd

There was an article, a couple of years ago, about substandard
capacitors being used in computer mother boards as they were much
cheaper. The article stated that a couple of engineers had left a
major capacitor making company and set up their own company aimed at
selling capacitors at a lower cost and left out some sort of
preservative in their capacitors. Whether true or not the latest
mother board I've bought had a statement on the box that it had
"improved, long life capacitors".
--
cheers,

John B.

In article 0, Lloyd
E. Sponenburgh wrote:

Spehro Pefhany fired this volley in
:

I suspect that what happens is that lighting and other transients
causes breakdown that causes a self-healing (because the short blows
away) short in the aluminized film. The value of the cap drops with
each surge until it's no longer high enough to support the motor
operation. The 5uF (?) one in my furnace draft inducer fan was down to
something like 1uF when it took out the fan motor (ouch$$$).

They've just pushed the thickness of the film down so far to save
money (and the volts/mil does not change) so the caps are more
susceptible to overvoltage spikes.


No, being an 'empirical chemist' one of my interests is in how polymers
act with time. Storage issues with pyrotechnic compositions containing
them is the matter at hand.

Most of the polymers used for the dielectric film undergo slow
degradation due to oxygen, chlorine, or sometimes even nitrogen in
contact with them.

They also can react (most slowly) to strong electrical fields across
them.

In any case, they slowly break down into compounds which are not
particularly good insulators, lowering the capacity, and eventually
allowing shorts to occur at the rated voltage.

It's not unexpected -- they make them to the BAREST minimums necessary to
manage the applied voltage, as it is.

Once, caps were 'over-rated'... no longer. Otherwise, the motor-start
capacitor guys would lose that 'replacement market'!

Umm. Capacitor dielectrics have gotten way better over the years.

Just buy the next highest voltage rating. This kind of derating is
standard practice. For film capacitors, a common rule is that
operating voltage be one half the rated steady-state voltage.

Joe Gwinn

On Tue, 18 Aug 2015 09:04:22 +0700, John B.
wrote:

On Mon, 17 Aug 2015 06:09:53 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Tom Gardner fired this volley in news:mqrt5r$90r$1
:

I have to replace my dual cap every 2 years, why don't they last?

I used to think it was "poor quality work", but I believe now that it's a
combination of the impact of "controlled substances" (like PCBs) and
deliberate planned-life designs.

Keep in mind that such caps are NOT considered a "user replacable part",
so if the electrical components industry can convince the end-user
"that's just the life of the part", then both the parts makers and the
local service companies benefit by getting more work.

When you add to that scheme the fact that the _right_ materials for
building a good (and compact) capacitor are mostly all illegal now, it
all seems to make sense.

And yes, they could still make good caps for military and high-end
commercial gear, but they usually MUCH larger, and might not fit in
equipment designed for the smaller form-factor parts. (plus the
exhorbitant prices)

LLoyd

There was an article, a couple of years ago, about substandard
capacitors being used in computer mother boards as they were much
cheaper. The article stated that a couple of engineers had left a
major capacitor making company and set up their own company aimed at
selling capacitors at a lower cost and left out some sort of
preservative in their capacitors. Whether true or not the latest
mother board I've bought had a statement on the box that it had
"improved, long life capacitors".

Almost right....you never heard the story about what happened?

http://www.theguardian.com/technolog...ems-capacitors

How a stolen capacitor formula ended up costing Dell $300m
Though the American company had nothing to do with the industrial
espionage in China in 2002 that led to faulty components, it paid the
price with millions of faulty PCs

Charles Arthur
@charlesarthur

Tuesday 29 June 2010 12.25 EDT Last modified on Monday 19 May 2014
19.40 EDT


Dell sold millions of computers between 2003 and 2005 that had faulty
components - specifically, capacitors, according to documents unsealed
in a case being heard in the federal court in North Carolina.

In an article in the New York Times, Ashlee Vance writes about the
problems that Dell faced - and how it tried to prevent them becoming
more widely known:

"Documents recently unsealed in a three-year-old lawsuit against
Dell show that the company's employees were actually aware that the
computers were likely to break. Still, the employees tried to play
down the problem to customers and allowed customers to rely on
trouble-prone machines, putting their businesses at risk. Even the
firm defending Dell in the lawsuit was affected when Dell balked at
fixing 1,000 suspect computers, according to e-mail messages revealed
in the dispute."

The documents do sound fascinating - though so far the only one from
the case that that has made it onto the wider web from the case is
this one - which is simply a list of documents that are no longer
sealed. (The case is being heard at the Federal District Court in
North Carolina.)

In 2005, Dell announced that it was taking a $300m charge to cover the
cost of fixing and/or replacing the faulty machines.

The NYT then argues that "The documents chronicling the failure of the
PCs also help explain the decline of one of America's most celebrated
and admired companies. Perhaps more than any other company, Dell
fought to lower the price of computers."

That may be true - but it's not the whole story. Dell ran afoul, quite
without realising it, of one of the most fascinating pieces of
industrial espionage of recent times: the theft of a formula for
making the electrolyte to go into capacitors from a Japanese company,
which got taken to China, and then onto Taiwan - but somewhere, got
messed up.

How do I know? Because I wrote about it seven years ago:

"A scientist steals a secret formula for an electrical product
from his Japanese employer and takes it to China. Then it is stolen
again and turns up in Taiwan. But something goes wrong - and
thousands, perhaps millions, of computers and electrical goods in the
West begin to burn out or explode.

"It sounds like the plot of a thriller, but it's reality.
Thousands of computers have failed and nobody is sure how many more
products might go wrong because their capacitors - essential
components to control the power supply - were made with faulty
materials."

In 2001, a scientist - name still unknown - left Rubycon Corporation
Japan to go and work for the Luminous Town Electric company in China.
Both companies made (among other things) electrolytic capacitors,
which are usually used in power circuits. At the LTE Company, the
scientist made a copy of the electrolyte - the chemical that goes
inside the capacitors and enhances its capacitative properties.

"Later that year, the scientist's staff defected to Taiwan, taking
with them a copy of the electrolyte formula so they could set up their
own company. Taiwan supplies 30 per cent of the world's electrolytic
capacitors and most of the big PC manufacturers get their machines
assembled in Taiwan. But the defectors mis-copied the formula. After a
few hours of operation, the electrolyte would leak hydrogen gas,
before bursting the metal body of the capacitor. The electrolyte would
then leak its brownish filling and could cause a fire."

IBM confessed to having a problem - and so too, privately, did Dell at
the time. But that was before it began selling millions of machines
which had a consistent problem: the capacitors weren't up to scratch.

Because according to the NYT story, the problem that kept cropping up
with those machines was, indeed, the capacitors. "The problems
affecting the Dell computers stemmed from an industrywide encounter
with bad capacitors produced by Asian PC component suppliers.
Capacitors are found on computer motherboards, playing a crucial role
in the flow of current across the hardware. They are not meant to pop
and leak fluid, but that is exactly what was happening earlier this
decade, causing computers made by Dell, Hewlett-Packard, Apple and
others to break."

Passive Component Industry Magazine (passive components are things
like capacitors and resistors) wrote about this in September 2002,
though it didn't know then quite how bad things would get. As Dell's
experience showed, it could get very bad indeed.

Back in 2003, Dennis Zogbi, president of Paumanok Publications, an
expert on the market for passive components, told me that the problem
is that "People want Western quality at Chinese prices," he said.
"Well, you can't have both."

The story continued well after that, though, with sites such as
Badcaps staying on the back of manufacturers including Apple which had
had the faulty components. Wikipedia refers to the "capacitor plague"
- and though it does seem to have gone into remittance now, Chris
Passalacqua, owner of Badcaps, suggests, "They didn't discover this
until it was too late and they had manufactured and distributed
literally MILLIONS of these flawed capacitors. However, it's been
going on way too long to simply blame on an industrial espionage
boo-boo in my humble opinion, as this problem is still extremely
common, and hasn't slowed down. Personally, I think it all boils down
to shoddy components that are manufactured by shoddy component
makers."

And that's where we circle back to Dell's problems. The NYT said that
"The documents chronicling the failure of the PCs also help explain
the decline of one of America's most celebrated and admired companies.
Perhaps more than any other company, Dell fought to lower the price of
computers." And that's certainly true: for years, Dell led because it
could undercut rivals, and kept pushing the price down.

But price and quality control are always in conflict - and in the end
that seems to have done for Dell. While other companies had the
capacitor problem too, they didn't suffer it as long as Dell appears
to have. So it was partly something Dell couldn't have expected to
have control over, namely the electrolyte formula in the capacitors in
the motherboards and/or power supplies - but also partly something
Dell could have acted on, which was the repeated failure of those
capacitors.

Meanwhile, if anyone does have a Pacer account and wants to repost
those court documents, please link them below."

It hit the entire computer industry HARD when it came out...each
company was going nutzo trying to minimize the expenses that they had
to fork over. Damned near killed a few companies as well.

http://www.geek.com/science/capacito...endors-551780/

http://www.nytimes.com/2010/06/29/te...gy/29dell.html

Etc etc etc

The problem went on for nearly a decade before they finally toughened
up and fixed it. Hence your labeling on the box

It wasnt just Dell or Gateway..but it was EVERYBODY who made
motherboards.

Gunner

On 8/17/2015 10:14 PM, Joe Gwinn wrote:
Just buy the next highest voltage rating. This kind of derating is
standard practice. For film capacitors, a common rule is that
operating voltage be one half the rated steady-state voltage.

Joe Gwinn


But most HVAC caps are dual caps, fan/pump. I haven't seen replacements
rated higher voltage of the same values. Can one use two discrete caps?

Tom Gardner fired this volley in news:mqufgp$qs1$2
@speranza.aioe.org:

Can one use two discrete caps?


Indeed. "Dual caps" are just a packaging convenience. They're
fundamentally a service problem, because if half fails, you must replace
both.

Most discrete-component television sets of the late 60s and early 70s that
ended up on a service bench could be seen to have had at least one dual cap
replaced with single-capacitor equivalents.

Lloyd

"Lloyd E. Sponenburgh" wrote:

Tom Gardner fired this volley in news:mqufgp$qs1$2
@speranza.aioe.org:

Can one use two discrete caps?


Indeed. "Dual caps" are just a packaging convenience. They're
fundamentally a service problem, because if half fails, you must replace
both.

Most discrete-component television sets of the late 60s and early 70s that
ended up on a service bench could be seen to have had at least one dual cap
replaced with single-capacitor equivalents.

Lloyd


A lot of TVs at that time used three or four section 'Twistlock'
electrolytics. The most common failure was the 160 uF 250 VDC
electrolytic used in the power supply of TVs without a power
transformer. They handled a lot of ripple current, and often swelled up,
blew the vent or exploded and filled the cabinet with shredded paper and
aluminum foil.

"Michael A. Terrell" fired this volley in
:


A lot of TVs at that time used three or four section 'Twistlock'
electrolytics. The most common failure was the 160 uF 250 VDC
electrolytic used in the power supply of TVs without a power
transformer. They handled a lot of ripple current, and often swelled
up,
blew the vent or exploded and filled the cabinet with shredded paper
and
aluminum foil.

Yeah... My Dad and I had the local Sears & Roebuck contract for about
five years in the late 60's. Their "Silvertone" line of TVs were just
junk. They combined EVERYthing they could into multi-component bundles,
without regard to performance. Dad would say, "They don't have enough
parts in 'em to make a decent radio!" G

They pretty much all had those quad-caps, and some of the multi-section
tubes with two to four discrete tube 'sections' in one envelope (like
those damnable 6AG11s).

Lloyd

"Lloyd E. Sponenburgh" wrote:

"Michael A. Terrell" fired this volley in
:


A lot of TVs at that time used three or four section 'Twistlock'
electrolytics. The most common failure was the 160 uF 250 VDC
electrolytic used in the power supply of TVs without a power
transformer. They handled a lot of ripple current, and often swelled
up,
blew the vent or exploded and filled the cabinet with shredded paper
and
aluminum foil.

Yeah... My Dad and I had the local Sears & Roebuck contract for about
five years in the late 60's. Their "Silvertone" line of TVs were just
junk. They combined EVERYthing they could into multi-component bundles,
without regard to performance. Dad would say, "They don't have enough
parts in 'em to make a decent radio!" G

They pretty much all had those quad-caps, and some of the multi-section
tubes with two to four discrete tube 'sections' in one envelope (like
those damnable 6AG11s).

At least the OEM was smart enough to use fusible resistors to prevent
fires. I forget who was the main TV supplier to Sears at the time, but I
met one of their engineers on a flight to a new assignment. He
complained about what they had to do to meet the Sears demands, and
price.

When Motorola quit building consumer electronics and sold it off as
Quasar, their TVs had over 100% failure rate off the production line.
Matsu****a closed the plant, replaced all the test equipment and put
every production worker through classes to improve their skills.
Motorola had run the facility into the ground, and no one gave a damn.
It was apparent in their products.

I don't have any 6AG11s, but I do have a few new 6AF11 & 6AL11 if you
need them ;-)

I bought the 6GH8A by the case of 100 at a time, in the '70s.

On 08/18/2015 12:23 AM, Tom Gardner wrote:
On 8/17/2015 10:14 PM, Joe Gwinn wrote:
Just buy the next highest voltage rating. This kind of derating is
standard practice. For film capacitors, a common rule is that
operating voltage be one half the rated steady-state voltage.

Joe Gwinn


But most HVAC caps are dual caps, fan/pump. I haven't seen replacements
rated higher voltage of the same values. Can one use two discrete caps?

Certainly, you can. You just need another wire to connect the common
terminal of the two caps together. But you might not find it easy
to get capacitors of those values with voltage ratings much higher
than the 440V of the ones you have now. And yes, it does need to be
that high even for a 240V supply. I measure 425V across the run cap
for my compressor. I'm sure it spikes higher than that during power
"events".

--
Bob Nichols AT comcast.net I am "RNichols42"

On Tue, 18 Aug 2015 09:18:31 -0400, "Michael A. Terrell"
wrote:


"Lloyd E. Sponenburgh" wrote:

"Michael A. Terrell" fired this volley in
:


A lot of TVs at that time used three or four section 'Twistlock'
electrolytics. The most common failure was the 160 uF 250 VDC
electrolytic used in the power supply of TVs without a power
transformer. They handled a lot of ripple current, and often swelled
up,
blew the vent or exploded and filled the cabinet with shredded paper
and
aluminum foil.

Yeah... My Dad and I had the local Sears & Roebuck contract for about
five years in the late 60's. Their "Silvertone" line of TVs were just
junk. They combined EVERYthing they could into multi-component bundles,
without regard to performance. Dad would say, "They don't have enough
parts in 'em to make a decent radio!" G

They pretty much all had those quad-caps, and some of the multi-section
tubes with two to four discrete tube 'sections' in one envelope (like
those damnable 6AG11s).

At least the OEM was smart enough to use fusible resistors to prevent
fires. I forget who was the main TV supplier to Sears at the time, but I
met one of their engineers on a flight to a new assignment. He
complained about what they had to do to meet the Sears demands, and
price.

When Motorola quit building consumer electronics and sold it off as
Quasar, their TVs had over 100% failure rate off the production line.
Matsu****a closed the plant, replaced all the test equipment and put
every production worker through classes to improve their skills.
Motorola had run the facility into the ground, and no one gave a damn.
It was apparent in their products.

I don't have any 6AG11s, but I do have a few new 6AF11 & 6AL11 if you
need them ;-)

I bought the 6GH8A by the case of 100 at a time, in the '70s.

Gizmag had an article yesterday which might interest you. It seems
that DARPA is hot for vacuum tubes.
http://www.gizmag.com/darpa-next-gen...m-tubes/38880/

--
The beauty of the 2nd Amendment is that it will not be needed
until they try to take it. --Thomas Jefferson

Larry Jaques fired this volley in
:

It seems
that DARPA is hot for vacuum tubes.


Without even reading it, I can understand why. Tubes are VERY immune to
EMF damage, while semiconductors seem to just belly-up and die at the least
excuse.

Lloyd

On 2015-08-18, Tom Gardner wrote:
On 8/17/2015 10:14 PM, Joe Gwinn wrote:
Just buy the next highest voltage rating. This kind of derating is
standard practice. For film capacitors, a common rule is that
operating voltage be one half the rated steady-state voltage.

But most HVAC caps are dual caps, fan/pump. I haven't seen replacements
rated higher voltage of the same values. Can one use two discrete caps?

Sure you can. They have a common point to which one side of
both caps are connected, and then the free end of each goes off to the
appropriate load. (The larger one to the compressor, the smaller to the
fan.)

For that matter -- the caps in my unit were replaced by a
special "replacement" cap which was in reality six caps of different
values, all connected to the one common, and the free end brought out to
a number of terminals. In practice, one was the right value to run the
fan, and all the rest in parallel added up to the value needed for the
compressor. (For those who don't know, capacitors in parallel add,
resistors in parallel produce a lower value. If only two, and both are
the same value, the result is half the value. If different values, or a
number in parallel, the math is a little more complex. Divide each
value into 1, add the results together, and then divide that value into
1 to get the result. Something similar is done for caps in series.

Enjoy,
DoN.

--
Remove oil spill source from e-mail
Email: | (KV4PH) Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On 2015-08-18, Lloyd E. Sponenburgh lloydspinsidemindspring.com wrote:
Tom Gardner fired this volley in news:mqufgp$qs1$2
@speranza.aioe.org:

Can one use two discrete caps?


Indeed. "Dual caps" are just a packaging convenience. They're
fundamentally a service problem, because if half fails, you must replace
both.

And, depending on the failure mode, it can make diagnosis a bit
more complex. Mine, when it failed, had the connection of the common of
the two caps to the common output terminal open, so in effect there was a
smaller value cap between the two load points. That was enough to start
the fan (with the compressor acting as a virtual ground), but far too
small to start the compressor, so it kept cycling, with the current
limit opening and then re-closing a few minutes later, resulting in a
repeated dimming of lights. And, when it tried to check it, it appeared
that the cap was good. :-)

Most discrete-component television sets of the late 60s and early 70s that
ended up on a service bench could be seen to have had at least one dual cap
replaced with single-capacitor equivalents.

Those would be the electrolytic caps, no doubt. (Mostly power
filter after rectifiers.) They had the common ground in the metal case,
and could benefit from the lowered cost of manufacture -- and the
lowered cost of mounting components.

Enjoy,
DoN.

--
Remove oil spill source from e-mail
Email: | (KV4PH) Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

In article , Tom Gardner
wrote:

On 8/17/2015 10:14 PM, Joe Gwinn wrote:
Just buy the next highest voltage rating. This kind of derating is
standard practice. For film capacitors, a common rule is that
operating voltage be one half the rated steady-state voltage.

Joe Gwinn


But most HVAC caps are dual caps, fan/pump. I haven't seen replacements
rated higher voltage of the same values. Can one use two discrete caps?

As many others have said, yes you can, and it's often a good idea.

Also, capacitor makers differ in how much safety margin they build in,
so buy only from the better brands.

Joe Gwinn

On 08/18/2015 08:43 PM, DoN. Nichols wrote:
On 2015-08-18, Lloyd E. Sponenburgh lloydspinsidemindspring.com wrote:
Tom Gardner fired this volley in news:mqufgp$qs1$2
@speranza.aioe.org:

Can one use two discrete caps?


Indeed. "Dual caps" are just a packaging convenience. They're
fundamentally a service problem, because if half fails, you must replace
both.

And, depending on the failure mode, it can make diagnosis a bit
more complex. Mine, when it failed, had the connection of the common of
the two caps to the common output terminal open, so in effect there was a
smaller value cap between the two load points. That was enough to start
the fan (with the compressor acting as a virtual ground), but far too
small to start the compressor, so it kept cycling, with the current
limit opening and then re-closing a few minutes later, resulting in a
repeated dimming of lights. And, when it tried to check it, it appeared
that the cap was good. :-)

The failure mode in mine has always been that the compressor cap blows
and causes the lid to dome upward, breaking the internal connection to
the fan cap. What makes it interesting is that I have a "hard start
kit" installed, and that's enough to get the compressor started. The
fan won't start without it's cap, so the compressor cycles on the
high pressure limit switch. I wish it would just lock itself out
instead of cycling that way repeatedly.

--
Bob Nichols AT comcast.net I am "RNichols42"

On Tue, 18 Aug 2015 10:24:47 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Larry Jaques fired this volley in
:

It seems
that DARPA is hot for vacuum tubes.


Without even reading it, I can understand why. Tubes are VERY immune to
EMF damage, while semiconductors seem to just belly-up and die at the least
excuse.

Good point. I hadn't thought about it from that aspect. Some muzzy
moron is surely going to set off an EMP bomb around the world
somewhere soon, so the quicker we find ways around it, the better. "We
live in 800AD, and so should you."

--
The beauty of the 2nd Amendment is that it will not be needed
until they try to take it. --Thomas Jefferson

On Wed, 19 Aug 2015 08:39:36 -0700, Larry Jaques
wrote:

On Tue, 18 Aug 2015 10:24:47 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Larry Jaques fired this volley in
m:

It seems
that DARPA is hot for vacuum tubes.


Without even reading it, I can understand why. Tubes are VERY immune to
EMF damage, while semiconductors seem to just belly-up and die at the least
excuse.

Good point. I hadn't thought about it from that aspect. Some muzzy
moron is surely going to set off an EMP bomb around the world
somewhere soon, so the quicker we find ways around it, the better. "We
live in 800AD, and so should you."
I was looking at some kits for making small pre-amps or amps for MP3
players that use very small tubes. I don't know much about how tubes
work. I know the basics but I don't know how the actual size of the
tube internals and their proximity to the other elements inside the
tube affects the operation of the tube. I imagine that today with
modern automation equipment that tubes could be made very small
indeed. Whether the tubes would operate the same as larger ones I have
no idea about but would like to know. I have seen pictures of devices
made and used in WWII that contained very small tubes that were used
in anti-aircraft shells to iniate the explosion when the shell was
close enough to an airplane. These tubes were essentially hand made
and even though tubes seem to me to be delicate these had to be made
to survive the acceleration of the anti-aircraft shell when fired from
a cannon.
Eric

On Tue, 18 Aug 2015 09:04:22 +0700, John B.
wrote:

On Mon, 17 Aug 2015 06:09:53 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Tom Gardner fired this volley in news:mqrt5r$90r$1
:

I have to replace my dual cap every 2 years, why don't they last?

I used to think it was "poor quality work", but I believe now that it's a
combination of the impact of "controlled substances" (like PCBs) and
deliberate planned-life designs.

Keep in mind that such caps are NOT considered a "user replacable part",
so if the electrical components industry can convince the end-user
"that's just the life of the part", then both the parts makers and the
local service companies benefit by getting more work.

When you add to that scheme the fact that the _right_ materials for
building a good (and compact) capacitor are mostly all illegal now, it
all seems to make sense.

And yes, they could still make good caps for military and high-end
commercial gear, but they usually MUCH larger, and might not fit in
equipment designed for the smaller form-factor parts. (plus the
exhorbitant prices)

LLoyd

There was an article, a couple of years ago, about substandard
capacitors being used in computer mother boards as they were much
cheaper. The article stated that a couple of engineers had left a
major capacitor making company and set up their own company aimed at
selling capacitors at a lower cost and left out some sort of
preservative in their capacitors. Whether true or not the latest
mother board I've bought had a statement on the box that it had
"improved, long life capacitors".
second son has built himself what ammounts to a "jumbotron" of 22"
monitors, simply by replacing caps in the power supply of out of
warranty units. He designed a replacement set of caps then bought in
bulk quantity.
---

Gerry :-)}
London,Canada

On Wed, 19 Aug 2015 20:12:40 -0400, wrote:

On Tue, 18 Aug 2015 09:04:22 +0700, John B.
wrote:

On Mon, 17 Aug 2015 06:09:53 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Tom Gardner fired this volley in news:mqrt5r$90r$1
:

I have to replace my dual cap every 2 years, why don't they last?

I used to think it was "poor quality work", but I believe now that it's a
combination of the impact of "controlled substances" (like PCBs) and
deliberate planned-life designs.

Keep in mind that such caps are NOT considered a "user replacable part",
so if the electrical components industry can convince the end-user
"that's just the life of the part", then both the parts makers and the
local service companies benefit by getting more work.

When you add to that scheme the fact that the _right_ materials for
building a good (and compact) capacitor are mostly all illegal now, it
all seems to make sense.

And yes, they could still make good caps for military and high-end
commercial gear, but they usually MUCH larger, and might not fit in
equipment designed for the smaller form-factor parts. (plus the
exhorbitant prices)

LLoyd

There was an article, a couple of years ago, about substandard
capacitors being used in computer mother boards as they were much
cheaper. The article stated that a couple of engineers had left a
major capacitor making company and set up their own company aimed at
selling capacitors at a lower cost and left out some sort of
preservative in their capacitors. Whether true or not the latest
mother board I've bought had a statement on the box that it had
"improved, long life capacitors".
second son has built himself what ammounts to a "jumbotron" of 22"
monitors, simply by replacing caps in the power supply of out of
warranty units. He designed a replacement set of caps then bought in
bulk quantity.

Cool. Got a list of those caps?

--
The beauty of the 2nd Amendment is that it will not be needed
until they try to take it. --Thomas Jefferson

On 2015-08-19, wrote:
On Wed, 19 Aug 2015 08:39:36 -0700, Larry Jaques
wrote:

On Tue, 18 Aug 2015 10:24:47 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Larry Jaques fired this volley in
:

It seems
that DARPA is hot for vacuum tubes.


Without even reading it, I can understand why. Tubes are VERY immune to
EMF damage, while semiconductors seem to just belly-up and die at the least
excuse.

Good point. I hadn't thought about it from that aspect. Some muzzy
moron is surely going to set off an EMP bomb around the world
somewhere soon, so the quicker we find ways around it, the better. "We
live in 800AD, and so should you."

This was one place where the Russian military aircraft had an
advantage over ours. But must have at least a backup tube based radio
if EMP takes out everything else.

I was looking at some kits for making small pre-amps or amps for MP3
players that use very small tubes. I don't know much about how tubes
work. I know the basics but I don't know how the actual size of the
tube internals and their proximity to the other elements inside the
tube affects the operation of the tube.

Well ... the distance of the grid from the cathode adjusts the
gain (assuming full emission from a fresh cathode), but the main thing
is that the smaller tubes can't handle as high a voltage for operation
-- though they could likely survive the EMP induced spikes.

I imagine that today with
modern automation equipment that tubes could be made very small
indeed. Whether the tubes would operate the same as larger ones I have
no idea about but would like to know.

Same principles, but less maximum voltage.

Note that in the 1970s and around then there were some very
small metal-cased tubes called "Nuvistors" -- about the same diameter as
a TO-5 transistor case, and three times as tall.

I have seen pictures of devices
made and used in WWII that contained very small tubes that were used
in anti-aircraft shells to iniate the explosion when the shell was
close enough to an airplane. These tubes were essentially hand made
and even though tubes seem to me to be delicate these had to be made
to survive the acceleration of the anti-aircraft shell when fired from
a cannon.

There were pencil tubes, mostly made by Raytheon, which had
numbers starting with "CK" like the early transistors from the same
company, such as the CK-722. I worked with those at the hobby level
when I was in high school. The pencil tubes had an end-on profile like
"()" and one end was squished flat with a number of evenly-spaced leads
coming out the seal. The other end was a little nipple where the vacuum
was pulled and them melted closed. I first saw one of these when I took
apart an old Radiosonde (a device sent up under a balloon to transmit
back the temperature, the humidity, and the barometric
pressure/altitude. (They knew how fast it should rise, so they could
determine the barometric pressure at the various altitudes. They were
launched from the local small-town airport, among other places, and were
powered by a weird battery which had several sections for different
voltages, and was activated by pouring water in through a hole in the
lid. A few minutes and it was producing full voltage. These were not
meant to be re-used, apparently.

Anyway -- aside from the pencil tube (and before the days of
practical transistors), there was another very specialized tube. about
2" long, with most of the length about 1/4" diameter, with a glass seal
in the middle where there was a disc of metal coming out to perhaps 1"
diameter which was the grid connection for that tube. Two pins on one
end for the filament. The cathode and plate connections were the 1/4"
cylindrical sections. Based on the length of the antenna (and things
which I learned later in life) it was probably operating in the range of
400-500 MHz.

And -- there were also what were called "Acorn tubes" (about the
size of an acorn), a little larger in diameter than the Nuvistors , with
the seal between a top and a bottom cap, and the leads coming out
radially. Those were used in walkie-talkies and the like in WW-II.

The major disadvantage of almost all tubes was that the
emissivity of the cathode would decrease with hours of use, so you had
to be able to re-adjust for the differing gain -- or design more complex
circuits which would automatically compensate for such drift.
Transistors tend to keep the same gain until they are over-voltaged or
over-currented at which point they stop working. :-) But in a
well-designed circuit, they are unlikely to be exposed to the excess
voltage or current.

Enjoy,
DoN.

--
Remove oil spill source from e-mail
Email: | (KV4PH) Voice (all times): (703) 938-4564
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--- Black Holes are where God is dividing by zero ---