Re: Ten-Tec Centurion, new tubes, idle current, glowing plates?
If your plate meter reads 125 ma at idle the tubes are immediately dissipating 375 watts with no drive. ?Immediately turning red on the bottom bell at 375watts is a bit quick. ?Are both tubes turning red about the same way or is one brother red thsn the other?
On Monday, July 15, 2024, 10:59 AM, Robin Midgett <RobinK4IDC@...> wrote: "Over time the bottom Bella of the tube will definitely turn red even with no drive."
The brand new tubes did this right out of the box...no time elapsed.
On Mon, Jul 15, 2024, 8:35 AM Louis Parascondola via <Gudguyham= [email protected]> wrote:
Oh Sorry, normal idle current is 125¨C160ma. Over time the bottom Bella of the tube will definitely turn red even with no drive.
On Monday, July 15, 2024, 9:27 AM, Robin Midgett <RobinK4IDC@...> wrote: Thanks for the info, Louis. To be clear, the photo you're referencing is from Bob W4JFA, not from me or my amplifier.? My tubes from Tom Rausch of CTR Engineering do have white bases. On Mon, Jul 15, 2024, 5:36 AM Louis Parascondola via <Gudguyham= [email protected]> wrote:
The tube in that photo, does that tube have a white base to it?? It looks like there is no white base and the white looks to be a reflection of the filament light.? If this is so, that tube didn¡¯t come from Tom at CTR.? Normal idle current on a pair of those tubes is around 125ma give or take a few.? THE PLATES WILL GET RED FOR SURE LIKE THAT OVER A PERIOD OF TIME.? That would be normal.? I¡¯m not sure however if that amp has electronic bias ? I know it has QSK but I think you can switch between PTT and QSK.? Tom tests all his tubes ?do if they are new the amp should be working normally.? But the tube in the pgmhoti doesn¡¯t seem to have any white base on it at all unless the photo is deceiving.
On Monday, July 15, 2024, 4:48 AM, Bob <W4JFABob@...> wrote: I hope the attached picture shows. This is a 3-500z with approx 90 - 100mA plate current after about 60 - 90 seconds. Bob W4JFA? On Mon, Jul 15, 2024, 1:23 AM Robin Midgett via <RobinK4IDC= [email protected]> wrote: I'd like to query the collective knowledge about a Ten-Tec Centurion amplifier I've been working on, if you'd be so kind as to respond:
I found that one tube had a cathode to grid short. I ordered and received a new pair of 3-500ZG tubes from Tom at CTR Engineering. I installed the tubes and it makes power.
With the amp keyed into a dummy?load & no drive, I see an indicated plate current of ~125mA, which I think is normal for a pair of 3-500Z tubes?in grounded grid; please comment on that. More to the point, the bases of the tube plates glow a dull red in that condition. I've been told by an elmer who I'm inclined to trust that the plates shouldn't glow with only 125mA plate current, and if they are glowing in keyed/idle, then the indicated plate current is likely false & for some reason greater than 125mA.
The original fault that I found is one tube has a short between grid and cathode, the other tube doesn't show any shorts. Is it possible or likely that some of the resistors used to derive?the plate current indication were damaged by the shorted grid/cathode condition?
If the plate current is greater than 125mA, what would cause that? I'm aware that Ten-Tec had some problems with bias from the QSK board in these amps for a time, but I don't know anything more about that. Any info is appreciated.
I recorded these parameters on each band; measurements taken from the front panel meters of the amp. I stopped at 1kW output because I don't have a slug for my Bird 43 that will indicate above 1kW on HF frequencies.?
?
| Band | Load | Tune | Pin | Pout | Iplate ma | Igrid ma | | 160 | 10 | 8 | 80 | 1kW | 600 | 180 | | 80 | 10 | 5 | 55 | 1kW | 630 | 140 | | 40 | 10 | 2.5 | 80 | 1kW | 440 | 160 | | 30 (40) | 1.6 | 0.75 | 50 | 1kW | 450 | 160 | | 20 | 6 | 0.75 | 50 | 1kW | 500 | 170 | | 17 (15) | 7.4 | 1.25 | 60 | 1kW | 630 | 160 | | 15 | 6 | 0.75 | 80 | 1kW | 530 | 160 | | 10 | 5 | 0.5 | 75 | 1kW | 600 | 160 |
|
Re: Ten-Tec Centurion, new tubes, idle current, glowing plates?
I think Lou meant after a period of being keyed, rather than the
age of the tubes.
73, Alek VK6APK
On 15/07/2024 10:58 pm, Robin Midgett
wrote:
toggle quoted message
Show quoted text
"Over time the bottom Bella of the tube will definitely
turn red even with no drive."
The brand new tubes did this right out of the
box...no time elapsed.
On Mon, Jul 15, 2024, 8:35
AM Louis Parascondola via <Gudguyham= [email protected]>
wrote:
Oh Sorry, normal idle current is 125¨C160ma. Over time
the bottom Bella of the tube will definitely turn red
even with no drive.
On
Monday, July 15, 2024, 9:27 AM, Robin Midgett <RobinK4IDC@...>
wrote:
Thanks for the info, Louis. To be clear,
the photo you're referencing is from Bob
W4JFA, not from me or my amplifier.?
My tubes from Tom Rausch of CTR Engineering
do have white bases.
On Mon, Jul 15, 2024, 5:36 AM
Louis Parascondola via
<Gudguyham= [email protected]>
wrote:
The tube in that photo, does that tube
have a white base to it?? It looks like
there is no white base and the white
looks to be a reflection of the filament
light.? If this is so, that tube didn¡¯t
come from Tom at CTR.? Normal idle
current on a pair of those tubes is
around 125ma give or take a few.? THE
PLATES WILL GET RED FOR SURE LIKE THAT
OVER A PERIOD OF TIME.? That would be
normal.? I¡¯m not sure however if that
amp has electronic bias ? I know it has
QSK but I think you can switch between
PTT and QSK.? Tom tests all his tubes
?do if they are new the amp should be
working normally.? But the tube in the
pgmhoti doesn¡¯t seem to have any white
base on it at all unless the photo is
deceiving.
On
Monday, July 15, 2024, 4:48 AM, Bob
<W4JFABob@...>
wrote:
I hope the attached picture
shows. This is a 3-500z with
approx 90 - 100mA plate current
after about 60 - 90 seconds.
Bob W4JFA?
On Mon, Jul 15,
2024, 1:23 AM Robin Midgett
via
<RobinK4IDC= [email protected]> wrote:
I'd
like to query the collective
knowledge about a Ten-Tec
Centurion amplifier I've
been working on, if you'd be
so kind as to respond:
I
found that one tube had a
cathode to grid short. I
ordered and received a new
pair of 3-500ZG tubes from
Tom at CTR Engineering. I
installed the tubes and it
makes power.
With the amp keyed into
a dummy?load & no
drive, I see an indicated
plate current of ~125mA,
which I think is normal
for a pair of 3-500Z
tubes?in grounded grid;
please comment on that.
More to the point, the
bases of the tube plates
glow a dull red in that
condition. I've been told
by an elmer who I'm
inclined to trust that the
plates shouldn't glow with
only 125mA plate current,
and if they are glowing in
keyed/idle, then the
indicated plate current is
likely false & for
some reason greater than
125mA.
The original fault that
I found is one tube has a
short between grid and
cathode, the other tube
doesn't show any shorts.
Is it possible or likely
that some of the resistors
used to derive?the plate
current indication were
damaged by the shorted
grid/cathode condition?
If the plate current is
greater than 125mA, what
would cause that? I'm
aware that Ten-Tec had
some problems with bias
from the QSK board in
these amps for a time, but
I don't know anything more
about that. Any info is
appreciated.
I recorded these
parameters on each band;
measurements taken from
the front panel meters of
the amp. I stopped at 1kW
output because I don't
have a slug for my Bird 43
that will indicate above
1kW on HF frequencies.?
?
| Band |
Load |
Tune |
Pin |
Pout |
Iplate
ma |
Igrid
ma |
| 160 |
10 |
8 |
80 |
1kW |
600 |
180 |
| 80 |
10 |
5 |
55 |
1kW |
630 |
140 |
| 40 |
10 |
2.5 |
80 |
1kW |
440 |
160 |
| 30
(40) |
1.6 |
0.75 |
50 |
1kW |
450 |
160 |
| 20 |
6 |
0.75 |
50 |
1kW |
500 |
170 |
| 17
(15) |
7.4 |
1.25 |
60 |
1kW |
630 |
160 |
| 15 |
6 |
0.75 |
80 |
1kW |
530 |
160 |
| 10 |
5 |
0.5 |
75 |
1kW |
600 |
160 |
|
Re: Ten-Tec Centurion, new tubes, idle current, glowing plates?
"Over time the bottom Bella of the tube will definitely turn red even with no drive."
The brand new tubes did this right out of the box...no time elapsed.
On Mon, Jul 15, 2024, 8:35 AM Louis Parascondola via <Gudguyham= [email protected]> wrote:
Oh Sorry, normal idle current is 125¨C160ma. Over time the bottom Bella of the tube will definitely turn red even with no drive.
On Monday, July 15, 2024, 9:27 AM, Robin Midgett <RobinK4IDC@...> wrote: Thanks for the info, Louis. To be clear, the photo you're referencing is from Bob W4JFA, not from me or my amplifier.? My tubes from Tom Rausch of CTR Engineering do have white bases. On Mon, Jul 15, 2024, 5:36 AM Louis Parascondola via <Gudguyham= [email protected]> wrote:
The tube in that photo, does that tube have a white base to it?? It looks like there is no white base and the white looks to be a reflection of the filament light.? If this is so, that tube didn¡¯t come from Tom at CTR.? Normal idle current on a pair of those tubes is around 125ma give or take a few.? THE PLATES WILL GET RED FOR SURE LIKE THAT OVER A PERIOD OF TIME.? That would be normal.? I¡¯m not sure however if that amp has electronic bias ? I know it has QSK but I think you can switch between PTT and QSK.? Tom tests all his tubes ?do if they are new the amp should be working normally.? But the tube in the pgmhoti doesn¡¯t seem to have any white base on it at all unless the photo is deceiving.
On Monday, July 15, 2024, 4:48 AM, Bob <W4JFABob@...> wrote: I hope the attached picture shows. This is a 3-500z with approx 90 - 100mA plate current after about 60 - 90 seconds. Bob W4JFA? On Mon, Jul 15, 2024, 1:23 AM Robin Midgett via <RobinK4IDC= [email protected]> wrote: I'd like to query the collective knowledge about a Ten-Tec Centurion amplifier I've been working on, if you'd be so kind as to respond:
I found that one tube had a cathode to grid short. I ordered and received a new pair of 3-500ZG tubes from Tom at CTR Engineering. I installed the tubes and it makes power.
With the amp keyed into a dummy?load & no drive, I see an indicated plate current of ~125mA, which I think is normal for a pair of 3-500Z tubes?in grounded grid; please comment on that. More to the point, the bases of the tube plates glow a dull red in that condition. I've been told by an elmer who I'm inclined to trust that the plates shouldn't glow with only 125mA plate current, and if they are glowing in keyed/idle, then the indicated plate current is likely false & for some reason greater than 125mA.
The original fault that I found is one tube has a short between grid and cathode, the other tube doesn't show any shorts. Is it possible or likely that some of the resistors used to derive?the plate current indication were damaged by the shorted grid/cathode condition?
If the plate current is greater than 125mA, what would cause that? I'm aware that Ten-Tec had some problems with bias from the QSK board in these amps for a time, but I don't know anything more about that. Any info is appreciated.
I recorded these parameters on each band; measurements taken from the front panel meters of the amp. I stopped at 1kW output because I don't have a slug for my Bird 43 that will indicate above 1kW on HF frequencies.?
?
| Band | Load | Tune | Pin | Pout | Iplate ma | Igrid ma | | 160 | 10 | 8 | 80 | 1kW | 600 | 180 | | 80 | 10 | 5 | 55 | 1kW | 630 | 140 | | 40 | 10 | 2.5 | 80 | 1kW | 440 | 160 | | 30 (40) | 1.6 | 0.75 | 50 | 1kW | 450 | 160 | | 20 | 6 | 0.75 | 50 | 1kW | 500 | 170 | | 17 (15) | 7.4 | 1.25 | 60 | 1kW | 630 | 160 | | 15 | 6 | 0.75 | 80 | 1kW | 530 | 160 | | 10 | 5 | 0.5 | 75 | 1kW | 600 | 160 |
|
Re: Ten-Tec Centurion, new tubes, idle current, glowing plates?
Thank you; I did not see this ammeter in the instructions manual. ? It seems difficult to manufacture power electronic tubes with a solid grid structure. Chinese manufactures often have a fragile grid. ? You have found a collapsed grid on the cathode (filament). It is possible that, for the tube that reddens at the bottom of the anode, the grid is deformed without yet touching the filament. The distribution of the electron flow between the catode and the anode is modified and this could be the cause of what you see (I do not see any other). -- F1AMM Fran?ois ? De la part de Robin Midgett
·¡²Ô±¹´Ç²â¨¦?: lundi 15 juillet 2024 15:18
|
Re: Ten-Tec Centurion, new tubes, idle current, glowing plates?
Oh Sorry, normal idle current is 125¨C160ma. Over time the bottom Bella of the tube will definitely turn red even with no drive.
On Monday, July 15, 2024, 9:27 AM, Robin Midgett <RobinK4IDC@...> wrote: Thanks for the info, Louis. To be clear, the photo you're referencing is from Bob W4JFA, not from me or my amplifier.? My tubes from Tom Rausch of CTR Engineering do have white bases. On Mon, Jul 15, 2024, 5:36 AM Louis Parascondola via <Gudguyham= [email protected]> wrote:
The tube in that photo, does that tube have a white base to it?? It looks like there is no white base and the white looks to be a reflection of the filament light.? If this is so, that tube didn¡¯t come from Tom at CTR.? Normal idle current on a pair of those tubes is around 125ma give or take a few.? THE PLATES WILL GET RED FOR SURE LIKE THAT OVER A PERIOD OF TIME.? That would be normal.? I¡¯m not sure however if that amp has electronic bias ? I know it has QSK but I think you can switch between PTT and QSK.? Tom tests all his tubes ?do if they are new the amp should be working normally.? But the tube in the pgmhoti doesn¡¯t seem to have any white base on it at all unless the photo is deceiving.
On Monday, July 15, 2024, 4:48 AM, Bob <W4JFABob@...> wrote: I hope the attached picture shows. This is a 3-500z with approx 90 - 100mA plate current after about 60 - 90 seconds. Bob W4JFA? On Mon, Jul 15, 2024, 1:23 AM Robin Midgett via <RobinK4IDC= [email protected]> wrote: I'd like to query the collective knowledge about a Ten-Tec Centurion amplifier I've been working on, if you'd be so kind as to respond:
I found that one tube had a cathode to grid short. I ordered and received a new pair of 3-500ZG tubes from Tom at CTR Engineering. I installed the tubes and it makes power.
With the amp keyed into a dummy?load & no drive, I see an indicated plate current of ~125mA, which I think is normal for a pair of 3-500Z tubes?in grounded grid; please comment on that. More to the point, the bases of the tube plates glow a dull red in that condition. I've been told by an elmer who I'm inclined to trust that the plates shouldn't glow with only 125mA plate current, and if they are glowing in keyed/idle, then the indicated plate current is likely false & for some reason greater than 125mA.
The original fault that I found is one tube has a short between grid and cathode, the other tube doesn't show any shorts. Is it possible or likely that some of the resistors used to derive?the plate current indication were damaged by the shorted grid/cathode condition?
If the plate current is greater than 125mA, what would cause that? I'm aware that Ten-Tec had some problems with bias from the QSK board in these amps for a time, but I don't know anything more about that. Any info is appreciated.
I recorded these parameters on each band; measurements taken from the front panel meters of the amp. I stopped at 1kW output because I don't have a slug for my Bird 43 that will indicate above 1kW on HF frequencies.?
?
| Band | Load | Tune | Pin | Pout | Iplate ma | Igrid ma | | 160 | 10 | 8 | 80 | 1kW | 600 | 180 | | 80 | 10 | 5 | 55 | 1kW | 630 | 140 | | 40 | 10 | 2.5 | 80 | 1kW | 440 | 160 | | 30 (40) | 1.6 | 0.75 | 50 | 1kW | 450 | 160 | | 20 | 6 | 0.75 | 50 | 1kW | 500 | 170 | | 17 (15) | 7.4 | 1.25 | 60 | 1kW | 630 | 160 | | 15 | 6 | 0.75 | 80 | 1kW | 530 | 160 | | 10 | 5 | 0.5 | 75 | 1kW | 600 | 160 |
|
Re: Ten-Tec Centurion, new tubes, idle current, glowing plates?
Thanks for the info, Louis. To be clear, the photo you're referencing is from Bob W4JFA, not from me or my amplifier.? My tubes from Tom Rausch of CTR Engineering do have white bases.
On Mon, Jul 15, 2024, 5:36 AM Louis Parascondola via <Gudguyham= [email protected]> wrote:
The tube in that photo, does that tube have a white base to it?? It looks like there is no white base and the white looks to be a reflection of the filament light.? If this is so, that tube didn¡¯t come from Tom at CTR.? Normal idle current on a pair of those tubes is around 125ma give or take a few.? THE PLATES WILL GET RED FOR SURE LIKE THAT OVER A PERIOD OF TIME.? That would be normal.? I¡¯m not sure however if that amp has electronic bias ? I know it has QSK but I think you can switch between PTT and QSK.? Tom tests all his tubes ?do if they are new the amp should be working normally.? But the tube in the pgmhoti doesn¡¯t seem to have any white base on it at all unless the photo is deceiving.
On Monday, July 15, 2024, 4:48 AM, Bob <W4JFABob@...> wrote: I hope the attached picture shows. This is a 3-500z with approx 90 - 100mA plate current after about 60 - 90 seconds. Bob W4JFA? On Mon, Jul 15, 2024, 1:23 AM Robin Midgett via <RobinK4IDC= [email protected]> wrote: I'd like to query the collective knowledge about a Ten-Tec Centurion amplifier I've been working on, if you'd be so kind as to respond:
I found that one tube had a cathode to grid short. I ordered and received a new pair of 3-500ZG tubes from Tom at CTR Engineering. I installed the tubes and it makes power.
With the amp keyed into a dummy?load & no drive, I see an indicated plate current of ~125mA, which I think is normal for a pair of 3-500Z tubes?in grounded grid; please comment on that. More to the point, the bases of the tube plates glow a dull red in that condition. I've been told by an elmer who I'm inclined to trust that the plates shouldn't glow with only 125mA plate current, and if they are glowing in keyed/idle, then the indicated plate current is likely false & for some reason greater than 125mA.
The original fault that I found is one tube has a short between grid and cathode, the other tube doesn't show any shorts. Is it possible or likely that some of the resistors used to derive?the plate current indication were damaged by the shorted grid/cathode condition?
If the plate current is greater than 125mA, what would cause that? I'm aware that Ten-Tec had some problems with bias from the QSK board in these amps for a time, but I don't know anything more about that. Any info is appreciated.
I recorded these parameters on each band; measurements taken from the front panel meters of the amp. I stopped at 1kW output because I don't have a slug for my Bird 43 that will indicate above 1kW on HF frequencies.?
?
| Band | Load | Tune | Pin | Pout | Iplate ma | Igrid ma | | 160 | 10 | 8 | 80 | 1kW | 600 | 180 | | 80 | 10 | 5 | 55 | 1kW | 630 | 140 | | 40 | 10 | 2.5 | 80 | 1kW | 440 | 160 | | 30 (40) | 1.6 | 0.75 | 50 | 1kW | 450 | 160 | | 20 | 6 | 0.75 | 50 | 1kW | 500 | 170 | | 17 (15) | 7.4 | 1.25 | 60 | 1kW | 630 | 160 | | 15 | 6 | 0.75 | 80 | 1kW | 530 | 160 | | 10 | 5 | 0.5 | 75 | 1kW | 600 | 160 |
|
Re: Ten-Tec Centurion, new tubes, idle current, glowing plates?
Thanks Bob. My tubes glow similarly in the lower plate portion when keyed without drive, but only a dull red. The photo you sent makes the plate look white hot...maybe it is an overexposed photo.
I hope the attached picture shows. This is a 3-500z with approx 90 - 100mA plate current after about 60 - 90 seconds. Bob W4JFA?
On Mon, Jul 15, 2024, 1:23 AM Robin Midgett via <RobinK4IDC= [email protected]> wrote: I'd like to query the collective knowledge about a Ten-Tec Centurion amplifier I've been working on, if you'd be so kind as to respond:
I found that one tube had a cathode to grid short. I ordered and received a new pair of 3-500ZG tubes from Tom at CTR Engineering. I installed the tubes and it makes power.
With the amp keyed into a dummy?load & no drive, I see an indicated plate current of ~125mA, which I think is normal for a pair of 3-500Z tubes?in grounded grid; please comment on that. More to the point, the bases of the tube plates glow a dull red in that condition. I've been told by an elmer who I'm inclined to trust that the plates shouldn't glow with only 125mA plate current, and if they are glowing in keyed/idle, then the indicated plate current is likely false & for some reason greater than 125mA.
The original fault that I found is one tube has a short between grid and cathode, the other tube doesn't show any shorts. Is it possible or likely that some of the resistors used to derive?the plate current indication were damaged by the shorted grid/cathode condition?
If the plate current is greater than 125mA, what would cause that? I'm aware that Ten-Tec had some problems with bias from the QSK board in these amps for a time, but I don't know anything more about that. Any info is appreciated.
I recorded these parameters on each band; measurements taken from the front panel meters of the amp. I stopped at 1kW output because I don't have a slug for my Bird 43 that will indicate above 1kW on HF frequencies.?
?
| Band |
Load |
Tune |
Pin |
Pout |
Iplate ma |
Igrid ma |
| 160 |
10 |
8 |
80 |
1kW |
600 |
180 |
| 80 |
10 |
5 |
55 |
1kW |
630 |
140 |
| 40 |
10 |
2.5 |
80 |
1kW |
440 |
160 |
| 30 (40) |
1.6 |
0.75 |
50 |
1kW |
450 |
160 |
| 20 |
6 |
0.75 |
50 |
1kW |
500 |
170 |
| 17 (15) |
7.4 |
1.25 |
60 |
1kW |
630 |
160 |
| 15 |
6 |
0.75 |
80 |
1kW |
530 |
160 |
| 10 |
5 |
0.5 |
75 |
1kW |
600 |
160 |
|
Re: Ten-Tec Centurion, new tubes, idle current, glowing plates?
Francois, In addition to the meter described in your quote from the manual, there is another meter dedicated to Iplate. It's a 0-1A meter.
> I see an indicated plate current of ~125mA ? How do you measure plate current?
? 
? -- F1AMM Fran?ois De la part de Bob
·¡²Ô±¹´Ç²â¨¦?: lundi 15 juillet 2024 10:48
|
Re: Ten-Tec Centurion, new tubes, idle current, glowing plates?
> I see an indicated plate current of ~125mA ? How do you measure plate current?
? 
? -- F1AMM Fran?ois De la part de Bob
·¡²Ô±¹´Ç²â¨¦?: lundi 15 juillet 2024 10:48
|
Re: Ten-Tec Centurion, new tubes, idle current, glowing plates?
The tube in that photo, does that tube have a white base to it? ?It looks like there is no white base and the white looks to be a reflection of the filament light. ?If this is so, that tube didn¡¯t come from Tom at CTR. ?Normal idle current on a pair of those tubes is around 125ma give or take a few. ?THE PLATES WILL GET RED FOR SURE LIKE THAT OVER A PERIOD OF TIME. ?That would be normal. ?I¡¯m not sure however if that amp has electronic bias ? I know it has QSK but I think you can switch between PTT and QSK. ?Tom tests all his tubes ?do if they are new the amp should be working normally. ?But the tube in the pgmhoti doesn¡¯t seem to have any white base on it at all unless the photo is deceiving.
On Monday, July 15, 2024, 4:48 AM, Bob <W4JFABob@...> wrote: I hope the attached picture shows. This is a 3-500z with approx 90 - 100mA plate current after about 60 - 90 seconds. Bob W4JFA? On Mon, Jul 15, 2024, 1:23 AM Robin Midgett via <RobinK4IDC= [email protected]> wrote: I'd like to query the collective knowledge about a Ten-Tec Centurion amplifier I've been working on, if you'd be so kind as to respond:
I found that one tube had a cathode to grid short. I ordered and received a new pair of 3-500ZG tubes from Tom at CTR Engineering. I installed the tubes and it makes power.
With the amp keyed into a dummy?load & no drive, I see an indicated plate current of ~125mA, which I think is normal for a pair of 3-500Z tubes?in grounded grid; please comment on that. More to the point, the bases of the tube plates glow a dull red in that condition. I've been told by an elmer who I'm inclined to trust that the plates shouldn't glow with only 125mA plate current, and if they are glowing in keyed/idle, then the indicated plate current is likely false & for some reason greater than 125mA.
The original fault that I found is one tube has a short between grid and cathode, the other tube doesn't show any shorts. Is it possible or likely that some of the resistors used to derive?the plate current indication were damaged by the shorted grid/cathode condition?
If the plate current is greater than 125mA, what would cause that? I'm aware that Ten-Tec had some problems with bias from the QSK board in these amps for a time, but I don't know anything more about that. Any info is appreciated.
I recorded these parameters on each band; measurements taken from the front panel meters of the amp. I stopped at 1kW output because I don't have a slug for my Bird 43 that will indicate above 1kW on HF frequencies.?
?
| Band | Load | Tune | Pin | Pout | Iplate ma | Igrid ma | | 160 | 10 | 8 | 80 | 1kW | 600 | 180 | | 80 | 10 | 5 | 55 | 1kW | 630 | 140 | | 40 | 10 | 2.5 | 80 | 1kW | 440 | 160 | | 30 (40) | 1.6 | 0.75 | 50 | 1kW | 450 | 160 | | 20 | 6 | 0.75 | 50 | 1kW | 500 | 170 | | 17 (15) | 7.4 | 1.25 | 60 | 1kW | 630 | 160 | | 15 | 6 | 0.75 | 80 | 1kW | 530 | 160 | | 10 | 5 | 0.5 | 75 | 1kW | 600 | 160 |
|
Re: Ten-Tec Centurion, new tubes, idle current, glowing plates?
I hope the attached picture shows. This is a 3-500z with approx 90 - 100mA plate current after about 60 - 90 seconds. Bob W4JFA?
On Mon, Jul 15, 2024, 1:23 AM Robin Midgett via <RobinK4IDC= [email protected]> wrote: I'd like to query the collective knowledge about a Ten-Tec Centurion amplifier I've been working on, if you'd be so kind as to respond:
I found that one tube had a cathode to grid short. I ordered and received a new pair of 3-500ZG tubes from Tom at CTR Engineering. I installed the tubes and it makes power.
With the amp keyed into a dummy?load & no drive, I see an indicated plate current of ~125mA, which I think is normal for a pair of 3-500Z tubes?in grounded grid; please comment on that. More to the point, the bases of the tube plates glow a dull red in that condition. I've been told by an elmer who I'm inclined to trust that the plates shouldn't glow with only 125mA plate current, and if they are glowing in keyed/idle, then the indicated plate current is likely false & for some reason greater than 125mA.
The original fault that I found is one tube has a short between grid and cathode, the other tube doesn't show any shorts. Is it possible or likely that some of the resistors used to derive?the plate current indication were damaged by the shorted grid/cathode condition?
If the plate current is greater than 125mA, what would cause that? I'm aware that Ten-Tec had some problems with bias from the QSK board in these amps for a time, but I don't know anything more about that. Any info is appreciated.
I recorded these parameters on each band; measurements taken from the front panel meters of the amp. I stopped at 1kW output because I don't have a slug for my Bird 43 that will indicate above 1kW on HF frequencies.?
?
| Band |
Load |
Tune |
Pin |
Pout |
Iplate ma |
Igrid ma |
| 160 |
10 |
8 |
80 |
1kW |
600 |
180 |
| 80 |
10 |
5 |
55 |
1kW |
630 |
140 |
| 40 |
10 |
2.5 |
80 |
1kW |
440 |
160 |
| 30 (40) |
1.6 |
0.75 |
50 |
1kW |
450 |
160 |
| 20 |
6 |
0.75 |
50 |
1kW |
500 |
170 |
| 17 (15) |
7.4 |
1.25 |
60 |
1kW |
630 |
160 |
| 15 |
6 |
0.75 |
80 |
1kW |
530 |
160 |
| 10 |
5 |
0.5 |
75 |
1kW |
600 |
160 |
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Ten-Tec Centurion, new tubes, idle current, glowing plates?
I'd like to query the collective knowledge about a Ten-Tec Centurion amplifier I've been working on, if you'd be so kind as to respond:
I found that one tube had a cathode to grid short. I ordered and received a new pair of 3-500ZG tubes from Tom at CTR Engineering. I installed the tubes and it makes power.
With the amp keyed into a dummy?load & no drive, I see an indicated plate current of ~125mA, which I think is normal for a pair of 3-500Z tubes?in grounded grid; please comment on that. More to the point, the bases of the tube plates glow a dull red in that condition. I've been told by an elmer who I'm inclined to trust that the plates shouldn't glow with only 125mA plate current, and if they are glowing in keyed/idle, then the indicated plate current is likely false & for some reason greater than 125mA.
The original fault that I found is one tube has a short between grid and cathode, the other tube doesn't show any shorts. Is it possible or likely that some of the resistors used to derive?the plate current indication were damaged by the shorted grid/cathode condition?
If the plate current is greater than 125mA, what would cause that? I'm aware that Ten-Tec had some problems with bias from the QSK board in these amps for a time, but I don't know anything more about that. Any info is appreciated.
I recorded these parameters on each band; measurements taken from the front panel meters of the amp. I stopped at 1kW output because I don't have a slug for my Bird 43 that will indicate above 1kW on HF frequencies.?
?
| Band |
Load |
Tune |
Pin |
Pout |
Iplate ma |
Igrid ma |
| 160 |
10 |
8 |
80 |
1kW |
600 |
180 |
| 80 |
10 |
5 |
55 |
1kW |
630 |
140 |
| 40 |
10 |
2.5 |
80 |
1kW |
440 |
160 |
| 30 (40) |
1.6 |
0.75 |
50 |
1kW |
450 |
160 |
| 20 |
6 |
0.75 |
50 |
1kW |
500 |
170 |
| 17 (15) |
7.4 |
1.25 |
60 |
1kW |
630 |
160 |
| 15 |
6 |
0.75 |
80 |
1kW |
530 |
160 |
| 10 |
5 |
0.5 |
75 |
1kW |
600 |
160 |
|
So I feel I found the culprit. I stuffed the on 572B on my tube tester just to see if the filament would light up. Nada! So I took a closer inspection of the tube and found the reason for no filament and why the components were zorched in the grid circuit. A picture is worth a thousand words. BTW the so-called ? watt on the grid was toasted also. Mod-U-Lator, Mike(y)/W3SLK ? ?
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Re: Bird Termaline load repair
Indeed, I kludged together an interface to a 12" long resistor and now I'm under 2:1 to 2 GHz.? There are a couple of "resonances" but I think that's because of the kludge (I was wanting to see if the short resistor was truly the cause of the problems).? More to be done but I'm on the right path.
Thanks Reid!
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Re: Henry Transformer Data sheet
I have a few transformer out of a hi power rf generator marked Camden Transformer Co. I have not been able to find any info on this company? The transformers are marked 1976. Any help would be appreciated.
This needs to go into the 'files' section.?
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Re: Henry Transformer Data sheet
This needs to go into the 'files' section.?
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Henry Transformer Data sheet
A friend sent me this sheet. I thought I would post it in case anyone needs it at a later date.? This also applies to many of the RF generators. C 
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Re: Bird Termaline load repair
GM! After seeing that I am positively certain the reason you don't have a flat match is someone kluged the short resistor in place with a copper pipe to extend it to the feed point. Putting the correct resistor in it should restore the factory performance.? ?Reid? W6MTF?
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Re: Bird Termaline load repair
So really the point is that I want the load to operate according to specifications:? VSWR 1.1:1 0-1 GHz; 1.25:1 1-2 GHz.? This one can't make spec above 30 MHz. Here is another picture of the innards.? At top is the tapered outer conductor.? Middle is the RF input (Bird QC connectorm, not visible to the right) and the inner conductor/resistor.? The copper piece interfacing directly with the resistor end is a screw-tightened clamp which is obviously hand-made.? The id of the fingerstock bit is 0.875", a perfect fit for 3/4" copper pipe, but not for any known (to me) non-inductive resistor. The tapered section looks similar to others I've seen online. I now have a 12" long 50 ohm non-inductive resistor, which will use up the entire length of the tapered section.? I can make more Cu plumbing to adapt the fingerstock to the resistor, but it just seems really odd to me that Bird would do it this way.? Wouldn't it have made more sense for the fingerstock to fit 1.0" id? 
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Re: Bird Termaline load repair
Typ, the local power company will give u a few gallons? of xfmr oil.? ?I used that in the heath dl....and also my HB? 8 gallon DL.? ?But neither are used above 10m.?
?
Mineral oil will work too, but has to be de-rated vs the real deal xfmr oil.? (note the 2 x graphs on the heath cantenna).? ?Bird used some esoteric silicone oil in their loads.?
?
OP, how much PO are u gonna put into a DL on 435 mhz ???
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Robin Midgett
Bob
Brandon DX