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Re: How to Getter a 3CX-3000A7 / 6000 / 10,000 , etc !

 

On Sep 24, 2006, at 2:09 PM, craxd wrote:

--- In ham_amplifiers@..., R L Measures <r@...> wrote:


On Sep 24, 2006, at 8:40 AM, Bill Turner wrote:

ORIGINAL MESSAGE:

On Sun, 24 Sep 2006 12:05:38 -0000, "pentalab" <jim.thomson@...>
wrote:

### Are u talking about 3-500Z's and 4-1000's ???? [glass
tubes] I have had new 4-1000's that glowed blue. It was
not gas either.... it was an anomoly/defect in the glass....per
Eimac. The glass would glow blue.... only when drive applied.
------------ REPLY FOLLOWS ------------

I don't think this is a defect. Many tubes show a fluorescence on
the
inside of the glass when operating. I was told it was "soft" x-
rays
caused by electrons impacting the anode and then striking the
glass.

I have seen this on 807s running at 750v with this glow on Tx. Soft
I've seen this in sweep tubes also many times. The glass had a blue
glow in places where there were holes open in the anode.
In the presence of an electrostatic field - such as that at the anode, electrons do not travel in a straight path.

I think Rich
is correct on this that some electrons escape, and strike the glass.
However, if the electron is out there at the glass, how does it get
replaced back into the cathode?

X-rays are more like >10,000v.
As I see it, the effect is caused by electrons from the cathode
missing the anode, striking the glass, and bumping electrons in the
fluxing agent up an a higher orbit When the electrons slow down they
fall back to their normal orbit and emit visible photons.

Whether that is the real cause or not, I've seen it many times.
Nothing to worry about.

The tubes that do not fluoresce probably have a different mix of
compounds or elements in the glass.
Agreed. There are several different fluxing agents used in glass
recipes.


This should not be confused with a blue glow between the elements.
That is gas and is something to worry about.
What's to worry about?, it's done.

Bill, W6WRT



Yahoo! Groups Links
R L MEASURES, AG6K. 805-386-3734
r@...
Best,

Will







Yahoo! Groups Links










R L MEASURES, AG6K. 805-386-3734
r@...


Re: How to Getter a 3CX-3000A7 / 6000 / 10,000 , etc !

 

On Sep 24, 2006, at 1:56 PM, craxd wrote:

Jim,

Did you ever get to speak to anyone at Eimac about where the getters
were at in a 3-500Z?
My take on gettering / gas contamination, or the lack thereof, is that it mainly came from a station who was trying to explain big-bang arcing in the output sections of HF/MF amplifiers by a means other than by an intermittent VHF parasite. However, since an arc in a near- vacuum is nearly silent acoustically-speaking, his internal-gas explanation of big-bang arcs did not wash. Other problems with his explanation is that tubes removed from amplifiers that sustained a big-bang arc typically show a normal vacuum on a high-potential tester, and that the VHF suppressor resistors from such amplifiers are often considerably higher in resistance than the marked value -- thereby suggesting the reason he didn't want.

That's a question I'd say a few of us would like
to find out about as I think there is some erroneous info floating
around on the net about it. One said it was the anode itself, but it
doesn't get hot enough in my opinion to do it,
Agreed, which is probably why the secret Admonishtrator (sic) bristled at your posts about this fly in his pie.

and would actually have
relaeased hydrogen gas if, a certain gettering material were applied
to it. Any thoughts on this?

73,

Will

--- In ham_amplifiers@..., "pentalab" <jim.thomson@...>
wrote:

--- In ham_amplifiers@..., R L Measures <r@...> wrote:

Do getters stop working when the HV is applied? ... when the
drive is applied? ... or when both are applied?

### getter's [per Eimac and Svetlana] are ALWAYS working...
as long as the fil is lit. HV + drive are not part of the
overall process.



ANY and
all residual gas and junk is absorbed by the getter's... and
you will never get any surprises... like any arcing from
anode to the grounded grid !!
I've fired up several gassy tubes, the insides glowed blue, but
none of them arced to the grid.

### Are u talking about 3-500Z's and 4-1000's ???? [glass
tubes] I have had new 4-1000's that glowed blue. It was
not gas either.... it was an anomoly/defect in the glass....per
Eimac. The glass would glow blue.... only when drive applied.

### Then I have also seen 4-1000's that glowed blue INSIDE the
anode/screen/grid compartment..... dunno if that was with drive
applied or not...... that was too long ago.

### With a big ceramic triode/terode.... I highly suspect... If
it's gassy... and BOTH HV and drive are applied.... arcs MIGHT
occur between anode to screen... or anode to grid.

### If the vac isn't good and hard in the 1st place.... that
could easily create even more problems.

### I had several 4-1000's yrs ago... that looked like a smoke
bomb going off inside.... when the fil V was applied!! They had
either a lousy vac.... or..'had gone to air'.

### did u ever see a blue glow inside the ceramic portion of a
metal tube ?? Kinda tough to see..with the chimney on.

### All I was trying to get at was.... if 16 guys say to use
48 hrs to getter a new/rebuilt tube.... and anything less is
gonna be a problem... cuz they have tried many diff time
frames... who am I to argue?

### Svetlana claims their tubes are proccesed at a higher temp
than Eimac [during the construction of the tube]... one would
think the Svetlana tubes would have less of a 'gas' problem
than an Eimac ?

### The Svetlana tubes all use a 'spiral mesh fil' and
where all the mesh criss crosses... they are welded. ... so
u don't wanna slam the fil V on.. it can buckle the mesh fil
sideways..esp with over rated fil xfmrs [eg: I use a 80 A
rated fil xfmr on my 50 A rated 3000A7]......... another reason
to step start em.

## I don't have the time or patience to inadvertantly destroy
expensive new/rebuilt tubes.

Later... Jim VE7RF


...
R L MEASURES, AG6K. 805-386-3734
r@...






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R L MEASURES, AG6K. 805-386-3734
r@...


Re: How to Getter a 3CX-3000A7 / 6000 / 10,000 , etc !

 

On Sep 24, 2006, at 7:36 PM, Bill Turner wrote:

ORIGINAL MESSAGE:

On Sun, 24 Sep 2006 17:59:19 -0700, R L Measures <r@...> wrote:


They can't reverse direction quick enough?
------------ REPLY FOLLOWS ------------

Perhaps so, but if they can accelerate to a certain speed in the half
inch or so between cathode and anode, why could they not decelerate an
equal amount a half inch after passing the anode? They would be
stopped in mid-space and immediately return to the anode like good
little electrons should. :-)
The evidence is that they strike glass, causing it ti fluoresce. I've seen 4-1000As with glass that turned pale brown where electrons had been banging it.

Or maybe the glass is too close to the anode so there is no time for
reversal before impacting the glass?

Bill, W6WRT





Yahoo! Groups Links










R L MEASURES, AG6K. 805-386-3734
r@...


Re: How to Getter a 3CX-3000A7 / 6000 / 10,000 , etc !

 

On Sep 24, 2006, at 7:25 PM, Bill Turner wrote:

ORIGINAL MESSAGE:

On Sun, 24 Sep 2006 13:38:32 -0400, Tony King - W4ZT
<w4zt-060920@...> wrote:

We had a discussion about fluorescence in ceramic tubes some time back
and I posted a few pictures of GS-35B's glowing in the dark
<>. The best explanation was electron bombardment
as opposed to soft X-rays. Just not enough voltage to accelerate the
electrons enough to generate the X-rays. Most of the pictures were taken
with less than 2500 Volts on the anode.

73, Tony W4ZT
------------ REPLY FOLLOWS ------------

One way to prove it once and for all would be to try to deflect the
beam with a magnet. Electrons would be deflected, x-rays would not.

Sound reasonable?
quite, provided the magnet is on a long enough, insulated stick.

Bill, W6WRT



Yahoo! Groups Links









R L MEASURES, AG6K. 805-386-3734
r@...


Re: How to Getter a 3CX-3000A7 / 6000 / 10,000 , etc !

pentalab
 

--- In ham_amplifiers@..., R L Measures <r@...> wrote:


On Sep 24, 2006, at 5:05 AM, pentalab wrote:

--- In ham_amplifiers@..., R L Measures <r@...>
wrote:

### getter's [per Eimac and Svetlana] are ALWAYS
working... as long as the fil is lit. HV + drive are not
part of the overall gettering process.


Rich- If this is the case, why not use the tubes as they are being
gettered? This has always been the way that I have done it.

### Hey Rich....... if you blow up ur new rebuilt Svetlana
4CX-10,000J... don't come whining to me !



### All I was trying to get at was.... if 16 guys say to
use 48 hrs to getter a new/rebuilt tube.... and anything less is
gonna be a problem... cuz they have tried many diff time
frames... who am I to argue?
Rich-I have run into a number of amateur radio dudes who advise
something that sounds semi-plausible, but instead of being based
in science, it turns out to be an artifice for promoting his guru
status by giving the appearance of having esoteric knowledge.

### Well these dudes were very adamant about the 48 hour
gettering process. Forget the science.... real life practical
experience is what counts. The tube is good for 35,000 hrs
b4 a rebuild..... so what if u leave the filament on for 48
hrs... it can't do any harm. A few of these fellows have a
LOT of experience with those tubes....... Jerry at Economy
Electronics buys the entire production run of YC-243's from
Eimac each month [socketless 6000A7]. He told me the same
deal..... 48 hrs.... or u could easily experience trbl.

### Eimac tells me the YC-243's that come in to be rebuilt, none
have had a fried grid in em... that's just a side story.



## I don't have the time or patience to inadvertantly
destroy expensive new/rebuilt tubes.

Rich - I have probably never run filaments for more than a minute
before firing up a new 3-500Z or 8170.

### 3-500Z's need the anodes to show colour to getter em.....
so whether u run the new 3-500Z fil for just a minute or 48
hrs is irelevant.

### How many DOZENS of new 8170's have you fired up ???

### You gotta be very carefull here Rich. Anecdotal experience
with just one of anything is no subsitute with experience
with hundreds of the same thing. When a fellow who sells
literally hundreds of big metal triodes/tetrodes.... and has a lot
of experience with em sez 8 hrs is not enough to getter
em.. or XYZ will happen..and does,.... and to use 48 hrs min....
I tend to listen.

### when guys tell me 1/2" tubing tank coils run so bloody
hot on 10m, they require 100-200 cfm.... I tend to listen,,,and
not try an re-invent the wheel. [on 10m, you can easily be
dissipating 200w of heat... all of it into just a 2-3 turn
coil.... as opposed to 120 watts of heat on 20m..... and way
more turns on 20m to boot]. Actually 3/4" is better.... and
strap... laid flat... like a parasitic suppressor wound on a
globar is the best for a 10m tank coil. Strap will have RF
flowing down both sides.... where as tubing only conducts on the
outside. 1.5" wide strap works superb... eq to 1"
tubing... and minimal stray C between turns.

Jim VE7RF


Re: How to Getter a 3CX-3000A7 / 6000 / 10,000 , etc !

craxd
 

Jim,

Below is a quote from Terman on this subject.

"Zirconium is also a useful metal in this regard. Zirconium at 1400
deg C will absorb copius quantities of such gasses as oxygen,
nitrogen, carbon monoxide, and carbon dioxide. The optimum temperature
for taking up hydrogen is 350 deg C, and at higher temperatures
hydrogen begins to be given off by the metal. As a result of these
properties it is possible to maintain an extremely high vacuum,
provided that there is zirconium in the tube at these two
temperatures. This can be accomplished either by employing two
zirconium filaments with different filament currents, or by using a
single piece of zirconium in which different parts of the metal are
raised to different temperatures, so that the temperature range
extends from 300 to 1400 deg C".

Terman references this;

Zirconium and its compounds with a high melting point. Phillips Tech
Journal, Worlds fair issue, 1939, by J. D. Fast.

According to the temp. chart by Tempil, 1400 deg C is yellow in color.
300 deg c is no color. I don't know of any 3-500z that would run this
color without melting the glass. Tempil manufacturers temperature
detection and measurement devices and the tempil stick paints. A copy
of the chart can be had here;



Thanks,

Will


--- In ham_amplifiers@..., "pentalab" <jim.thomson@...>
wrote:

--- In ham_amplifiers@..., "craxd" <craxd1@> wrote:

Jim,

Did you ever get to speak to anyone at Eimac about where the
getters
were at in a 3-500Z? That's a question I'd say a few of us would
like
to find out about as I think there is some erroneous info floating
around on the net about it. One said it was the anode itself, but
it
doesn't get hot enough in my opinion to do it, and would actually
have
relaeased hydrogen gas if, a certain gettering material were
applied
to it. Any thoughts on this?

73,

Will
### No I have not. 1 e-mail to eimac ought end the
discussion . Rauch claims amperex etc... all use zirconium
coated anodes... and gettwring is done when tubes shoe
colour... aprx 800 deg C. I'm inclined to agree. A 3-500Z
has no internal getter........ so it's either the tube has
zirconium on the anode..... or it has NO getter at all !

Jim VE7RF


Re: How to Getter a 3CX-3000A7 / 6000 / 10,000 , etc !

pentalab
 

--- In ham_amplifiers@..., "craxd" <craxd1@...> wrote:

Jim,

Did you ever get to speak to anyone at Eimac about where the
getters
were at in a 3-500Z? That's a question I'd say a few of us would
like
to find out about as I think there is some erroneous info floating
around on the net about it. One said it was the anode itself, but
it
doesn't get hot enough in my opinion to do it, and would actually
have
relaeased hydrogen gas if, a certain gettering material were
applied
to it. Any thoughts on this?

73,

Will
### No I have not. 1 e-mail to eimac ought end the
discussion . Rauch claims amperex etc... all use zirconium
coated anodes... and gettwring is done when tubes shoe
colour... aprx 800 deg C. I'm inclined to agree. A 3-500Z
has no internal getter........ so it's either the tube has
zirconium on the anode..... or it has NO getter at all !

Jim VE7RF


Re: How to manage Filament Voltage on a 3000/6000/10,000A7 triode or tetrode

pentalab
 

--- In ham_amplifiers@..., "Peter Voelpel" <df3kv@...>
wrote:


Hi Jim,

I understand that tube life is dependend on their vacuum and on
the emission
from the cathode such that material of it disappears until worn,
and then
the tube is probably send in for a new coating.
How does ?the clock tick? when just the heater is lit and no
current flows?
73, Peter
### anode/grid current/drive power has nothing to do with
emmision. Take 2 x identical linear's..... one with just the
fil /blower on.[no HV no drive applied] ..and the 2nd linear
with HV on and drive applied [dead cxr]. The tube in each
amp will lose emmision at the SAME rate.

### after XXX hours.... the tube in each amp will need to be
sent in for a rebuild.

### Hence.... 'when the fil is lit, the clock is ticking'

Jim VE7RF


Re: How to Getter a 3CX-3000A7 / 6000 / 10,000 , etc !

Tony King - W4ZT
 

That's an excellent idea Bill. I will have to try that the next time I test GS-35B's. Don't know if I will be able to see much with the ceramic but I would bet it would be easy to see with glass tubes. Maybe someone else could report on that one. One of these new small space age magnets should produce enough magnetic field. Stuck on the end of a large tywrap should make it safe enough.

73, Tony W4ZT

Bill Turner wrote:

ORIGINAL MESSAGE:
On Sun, 24 Sep 2006 13:38:32 -0400, Tony King - W4ZT
<w4zt-060920@...> wrote:

We had a discussion about fluorescence in ceramic tubes some time back and I posted a few pictures of GS-35B's glowing in the dark <>. The best explanation was electron bombardment as opposed to soft X-rays. Just not enough voltage to accelerate the electrons enough to generate the X-rays. Most of the pictures were taken with less than 2500 Volts on the anode.

73, Tony W4ZT
------------ REPLY FOLLOWS ------------
One way to prove it once and for all would be to try to deflect the
beam with a magnet. Electrons would be deflected, x-rays would not.
Sound reasonable?
Bill, W6WRT


Re: How to Getter a 3CX-3000A7 / 6000 / 10,000 , etc !

Bill Turner
 

ORIGINAL MESSAGE:

On Sun, 24 Sep 2006 17:59:19 -0700, R L Measures <r@...> wrote:


They can't reverse direction quick enough?
------------ REPLY FOLLOWS ------------

Perhaps so, but if they can accelerate to a certain speed in the half
inch or so between cathode and anode, why could they not decelerate an
equal amount a half inch after passing the anode? They would be
stopped in mid-space and immediately return to the anode like good
little electrons should. :-)

Or maybe the glass is too close to the anode so there is no time for
reversal before impacting the glass?

Bill, W6WRT


Re: How to Getter a 3CX-3000A7 / 6000 / 10,000 , etc !

Bill Turner
 

ORIGINAL MESSAGE:

On Sun, 24 Sep 2006 13:38:32 -0400, Tony King - W4ZT
<w4zt-060920@...> wrote:

We had a discussion about fluorescence in ceramic tubes some time back
and I posted a few pictures of GS-35B's glowing in the dark
<>. The best explanation was electron bombardment
as opposed to soft X-rays. Just not enough voltage to accelerate the
electrons enough to generate the X-rays. Most of the pictures were taken
with less than 2500 Volts on the anode.

73, Tony W4ZT
------------ REPLY FOLLOWS ------------

One way to prove it once and for all would be to try to deflect the
beam with a magnet. Electrons would be deflected, x-rays would not.

Sound reasonable?

Bill, W6WRT


Re: Jumbo sized lytic stack for HV supplies ! Oil cap warning. DIODES

FRANCIS CARCIA
 

I use HN connectors for high voltage and use RG213 as a conductor. the chassis side I found a mate with a long leakage path. wa1gfz

pentalab wrote:

--- In ham_amplifiers@yahoogroups.com, PA3DUV wrote:
>
> Also the SHV will accept RG8U coax only.

### If that's the case... then it will also accept Teflon RG-
393 coax.... which is a bit smaller OD than 8-U/213-U [.390"
OD for 393 coax.... vs .405" OD for 8-U /213-U
Jim VE7RF

> Actually the H+S SHV is the same type as the Kings HT connectors,
a bit flimsy.
> I just browsed the site. (Thanks
Greg!)
> These look better to me, are mechanical sound, accept 11/12 mm
coax as well and can be supplied with nice bend restrictors.
>
> Cheers, Dick
> PA3DUV
>



Re: How to Getter a 3CX-3000A7 / 6000 / 10,000 , etc !

 

On Sep 24, 2006, at 10:25 AM, Bill Turner wrote:

ORIGINAL MESSAGE:

On Sun, 24 Sep 2006 10:12:39 -0700, R L Measures <r@...> wrote:


I have seen this on 807s running at 750v with this glow on Tx. Soft
X-rays are more like >10,000v.
As I see it, the effect is caused by electrons from the cathode
missing the anode, striking the glass, and bumping electrons in the
fluxing agent up an a higher orbit When the electrons slow down they
fall back to their normal orbit and emit visible photons.
------------ REPLY FOLLOWS ------------

Wouldn't electrons which "miss" the anode be immediately attracted
back to the outside of the anode? Why would they continue out to the
glass instead of circling back?
They can't reverse direction quick enough?

Some interesting physics here.

Bill, W6WRT



Yahoo! Groups Links










R L MEASURES, AG6K. 805-386-3734
r@...


Re: How to Getter a 3CX-3000A7 / 6000 / 10,000 , etc !

craxd
 

--- In ham_amplifiers@..., R L Measures <r@...> wrote:


On Sep 24, 2006, at 8:40 AM, Bill Turner wrote:

ORIGINAL MESSAGE:

On Sun, 24 Sep 2006 12:05:38 -0000, "pentalab" <jim.thomson@...>
wrote:

### Are u talking about 3-500Z's and 4-1000's ???? [glass
tubes] I have had new 4-1000's that glowed blue. It was
not gas either.... it was an anomoly/defect in the glass....per
Eimac. The glass would glow blue.... only when drive applied.
------------ REPLY FOLLOWS ------------

I don't think this is a defect. Many tubes show a fluorescence on
the
inside of the glass when operating. I was told it was "soft" x-
rays
caused by electrons impacting the anode and then striking the
glass.

I have seen this on 807s running at 750v with this glow on Tx. Soft
I've seen this in sweep tubes also many times. The glass had a blue
glow in places where there were holes open in the anode. I think Rich
is correct on this that some electrons escape, and strike the glass.
However, if the electron is out there at the glass, how does it get
replaced back into the cathode?

X-rays are more like >10,000v.
As I see it, the effect is caused by electrons from the cathode
missing the anode, striking the glass, and bumping electrons in the
fluxing agent up an a higher orbit When the electrons slow down they
fall back to their normal orbit and emit visible photons.

Whether that is the real cause or not, I've seen it many times.
Nothing to worry about.

The tubes that do not fluoresce probably have a different mix of
compounds or elements in the glass.
Agreed. There are several different fluxing agents used in glass
recipes.


This should not be confused with a blue glow between the elements.
That is gas and is something to worry about.
What's to worry about?, it's done.

Bill, W6WRT



Yahoo! Groups Links
R L MEASURES, AG6K. 805-386-3734
r@...
Best,

Will


Re: How to Getter a 3CX-3000A7 / 6000 / 10,000 , etc !

Peter Voelpel
 

Gettering of those and similar tubes is done by the anode coating.
One reason they have to be driven red, which is about 800¡ãC

73
Peter

________________________________

Subject: [ham_amplifiers] Re: How to Getter a 3CX-3000A7 / 6000 / 10,000 ,
etc !

Did you ever get to speak to anyone at Eimac about where the getters
were at in a 3-500Z? That's a question I'd say a few of us would like
to find out about as I think there is some erroneous info floating
around on the net about it. One said it was the anode itself, but it
doesn't get hot enough in my opinion to do it, and would actually have
relaeased hydrogen gas if, a certain gettering material were applied
to it. Any thoughts on this?


Re: How to Getter a 3CX-3000A7 / 6000 / 10,000 , etc !

craxd
 

Jim,

Did you ever get to speak to anyone at Eimac about where the getters
were at in a 3-500Z? That's a question I'd say a few of us would like
to find out about as I think there is some erroneous info floating
around on the net about it. One said it was the anode itself, but it
doesn't get hot enough in my opinion to do it, and would actually have
relaeased hydrogen gas if, a certain gettering material were applied
to it. Any thoughts on this?

73,

Will

--- In ham_amplifiers@..., "pentalab" <jim.thomson@...>
wrote:

--- In ham_amplifiers@..., R L Measures <r@...> wrote:

Do getters stop working when the HV is applied? ... when the
drive is applied? ... or when both are applied?

### getter's [per Eimac and Svetlana] are ALWAYS working...
as long as the fil is lit. HV + drive are not part of the
overall process.



ANY and
all residual gas and junk is absorbed by the getter's... and
you will never get any surprises... like any arcing from
anode to the grounded grid !!
I've fired up several gassy tubes, the insides glowed blue, but
none of them arced to the grid.

### Are u talking about 3-500Z's and 4-1000's ???? [glass
tubes] I have had new 4-1000's that glowed blue. It was
not gas either.... it was an anomoly/defect in the glass....per
Eimac. The glass would glow blue.... only when drive applied.

### Then I have also seen 4-1000's that glowed blue INSIDE the
anode/screen/grid compartment..... dunno if that was with drive
applied or not...... that was too long ago.

### With a big ceramic triode/terode.... I highly suspect... If
it's gassy... and BOTH HV and drive are applied.... arcs MIGHT
occur between anode to screen... or anode to grid.

### If the vac isn't good and hard in the 1st place.... that
could easily create even more problems.

### I had several 4-1000's yrs ago... that looked like a smoke
bomb going off inside.... when the fil V was applied!! They had
either a lousy vac.... or..'had gone to air'.

### did u ever see a blue glow inside the ceramic portion of a
metal tube ?? Kinda tough to see..with the chimney on.

### All I was trying to get at was.... if 16 guys say to use
48 hrs to getter a new/rebuilt tube.... and anything less is
gonna be a problem... cuz they have tried many diff time
frames... who am I to argue?

### Svetlana claims their tubes are proccesed at a higher temp
than Eimac [during the construction of the tube]... one would
think the Svetlana tubes would have less of a 'gas' problem
than an Eimac ?

### The Svetlana tubes all use a 'spiral mesh fil' and
where all the mesh criss crosses... they are welded. ... so
u don't wanna slam the fil V on.. it can buckle the mesh fil
sideways..esp with over rated fil xfmrs [eg: I use a 80 A
rated fil xfmr on my 50 A rated 3000A7]......... another reason
to step start em.

## I don't have the time or patience to inadvertantly destroy
expensive new/rebuilt tubes.

Later... Jim VE7RF


...
R L MEASURES, AG6K. 805-386-3734
r@...


Re: How to manage Filament Voltage on a 3000/6000/10,000A7 triode or tetrode

Peter Voelpel
 

Hi Jim,

I understand that tube life is dependend on their vacuum and on the emission
from the cathode such that material of it disappears until worn, and then
the tube is probably send in for a new coating.
How does ?the clock tick? when just the heater is lit and no current flows?
73, Peter


________________________________

From: ham_amplifiers@... [mailto:ham_amplifiers@...]
On Behalf Of pentalab

Always remember.... when the fil is lit...'the clock is ticking'.


Re: How to Getter a 3CX-3000A7 / 6000 / 10,000 , etc !

Tony King - W4ZT
 

Bill Turner wrote:
<snip>
Wouldn't electrons which "miss" the anode be immediately attracted
back to the outside of the anode? Why would they continue out to the
glass instead of circling back?
Some interesting physics here. Bill, W6WRT
They're moving too fast to circle back in that distance.

We had a discussion about fluorescence in ceramic tubes some time back and I posted a few pictures of GS-35B's glowing in the dark <>. The best explanation was electron bombardment as opposed to soft X-rays. Just not enough voltage to accelerate the electrons enough to generate the X-rays. Most of the pictures were taken with less than 2500 Volts on the anode.

73, Tony W4ZT


Re: How to Getter a 3CX-3000A7 / 6000 / 10,000 , etc !

Bill Turner
 

ORIGINAL MESSAGE:

On Sun, 24 Sep 2006 10:12:39 -0700, R L Measures <r@...> wrote:


I have seen this on 807s running at 750v with this glow on Tx. Soft
X-rays are more like >10,000v.
As I see it, the effect is caused by electrons from the cathode
missing the anode, striking the glass, and bumping electrons in the
fluxing agent up an a higher orbit When the electrons slow down they
fall back to their normal orbit and emit visible photons.
------------ REPLY FOLLOWS ------------

Wouldn't electrons which "miss" the anode be immediately attracted
back to the outside of the anode? Why would they continue out to the
glass instead of circling back?

Some interesting physics here.

Bill, W6WRT


Re: How to Getter a 3CX-3000A7 / 6000 / 10,000 , etc !

 

On Sep 24, 2006, at 8:40 AM, Bill Turner wrote:

ORIGINAL MESSAGE:

On Sun, 24 Sep 2006 12:05:38 -0000, "pentalab" <jim.thomson@...>
wrote:

### Are u talking about 3-500Z's and 4-1000's ???? [glass
tubes] I have had new 4-1000's that glowed blue. It was
not gas either.... it was an anomoly/defect in the glass....per
Eimac. The glass would glow blue.... only when drive applied.
------------ REPLY FOLLOWS ------------

I don't think this is a defect. Many tubes show a fluorescence on the
inside of the glass when operating. I was told it was "soft" x-rays
caused by electrons impacting the anode and then striking the glass.
I have seen this on 807s running at 750v with this glow on Tx. Soft X-rays are more like >10,000v.
As I see it, the effect is caused by electrons from the cathode missing the anode, striking the glass, and bumping electrons in the fluxing agent up an a higher orbit When the electrons slow down they fall back to their normal orbit and emit visible photons.

Whether that is the real cause or not, I've seen it many times.
Nothing to worry about.

The tubes that do not fluoresce probably have a different mix of
compounds or elements in the glass.
Agreed. There are several different fluxing agents used in glass recipes.


This should not be confused with a blue glow between the elements.
That is gas and is something to worry about.
What's to worry about?, it's done.

Bill, W6WRT



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