I’m in need of a 0~1mA meter for an original AL-80, (ala Prime) amplifier. The one that is in there now has a bad set of ‘innards’. We can use the meter face from the original if I can find a same size one. TNX. ? Mod-U-Lator, Mike(y)/W3SLK ? ?
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Hi all,
I'm in the beginning of planning on replacing the slow mechanical TR switches/relays in my 2K-3. Looking at the schematic it appears pretty straight forward. 12v to each relay.
I have three questions about this... 1. Does anyone have an opinion on which vacuum relays to use? 2. How do I sequence them? 3. Ideas on physically?mounting them.
Any opinions would be appreciated.
Thank You very much.
Bob W4JFA
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Re: Ten-Tec Centurion, new tubes, idle current, glowing plates?
Hi Bob – ? Good hearing from you. Please reply direct at n4fs@.... Thanks & 73 – Mike ? Mike B. Feher, N4FS 89 Arnold Blvd. Howell NJ 07731 908-902-3831 ?
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From: [email protected] < [email protected]> On Behalf Of Robert Zaepfel via groups.io Sent: Wednesday, July 24, 2024 3:40 PM To: [email protected]Subject: Re: [ham-amplifiers] Ten-Tec Centurion, new tubes, idle current, glowing plates? ? I just happened to see this on the reflector. Haven't heard anything about you in a long time. Last I heard was from Butch a few years ago. I do hope you are well. Probably retired by now. We're all doing okay here. Kathy has dementia. Very sad. I'm still active on 40 and 20. Build a little and keep on plugging. I'm 81 now.?
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Re: Ten-Tec Centurion, new tubes, idle current, glowing plates?
Hey Mike,
I just happened to see this on the reflector. Haven't heard anything about you in a long time. Last I heard was from Butch a few years ago. I do hope you are well. Probably retired by now. We're all doing okay here. Kathy has dementia. Very sad. I'm still active on 40 and 20. Build a little and keep on plugging. I'm 81 now.?
All the best,
Bob Zaepfel, K4HJF
Seems to me that a burnt shunt would make the meter read high. 73 – Mike ? Mike B. Feher, N4FS 89 Arnold Blvd. Howell NJ 07731 908-902-3831 ?
From: [email protected] <[email protected]> On Behalf Of Chuck Neal via groups.io
Sent: Monday, July 15, 2024 9:06 PM
To: [email protected]
Subject: Re: [ham-amplifiers] Ten-Tec Centurion, new tubes, idle current, glowing plates? ? Sounds like two problems at once ? 1) Plate meter is reading low, perhaps due to a burnt shunt resistor in the metering circuit ? AND ? 2) Bias supply is not working depending on the plate voltage in that amp.? Not familiar with that amp’s plate voltage but “zero bias” tubes like 3-500’s do need some minimal bias, like 5 – 8 V negative, again depending upon plate voltage. ? -Chuck K1KW ? ? 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 125–160ma. 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. ? 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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Re: Bird Termaline load repair
Great work, Scott! Do you have a photo of the finished?product before final assembly to share?
The End--success!
The fix was a combination of (1) a 12" long resistor that could run the entire length of the tapered outer conductor, and (2) the shortest, neatest transition from the 0.875" id fingerstock cup to the 1.0" od of the resistor at the wide (input) end.? Copper plumbing adapters came in handy.
PS it DOES make a difference to have the assembly in the oil--outside the oil the worst VSWR (up to 2 GHz) was 1.9:1, and once in the oil the worst VSWR dropped to 1.45:1.? Still not "to spec" but certainly usable.
A bit more digging revealed that this load was roughly 1975 vintage.? Back then there must have been some company that made 7/8"x12" non-inductive resistors that would fit into that fingerstock cup...or perhaps Bird had them made custom.? The latter would make sense as you cannot buy only a replacement resistor from Bird--you have to buy the entire drop-it-in-the-oil assembly (for the low, low price of $1700+).
Bird was of absolutely no help, but I suppose I should cut them some slack given that this thing is pushing 50 years old.
?
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Re: Bird Termaline load repair
The End--success!
The fix was a combination of (1) a 12" long resistor that could run the entire length of the tapered outer conductor, and (2) the shortest, neatest transition from the 0.875" id fingerstock cup to the 1.0" od of the resistor at the wide (input) end.? Copper plumbing adapters came in handy.
PS it DOES make a difference to have the assembly in the oil--outside the oil the worst VSWR (up to 2 GHz) was 1.9:1, and once in the oil the worst VSWR dropped to 1.45:1.? Still not "to spec" but certainly usable.
A bit more digging revealed that this load was roughly 1975 vintage.? Back then there must have been some company that made 7/8"x12" non-inductive resistors that would fit into that fingerstock cup...or perhaps Bird had them made custom.? The latter would make sense as you cannot buy only a replacement resistor from Bird--you have to buy the entire drop-it-in-the-oil assembly (for the low, low price of $1700+).
Bird was of absolutely no help, but I suppose I should cut them some slack given that this thing is pushing 50 years old.
?
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Re: Ten-Tec Centurion, new tubes, idle current, glowing plates?
Hi Bill,
Many thanks, I'll install the TranZorb device while I'm checking out the bias circuitry.?
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Re: Ten-Tec Centurion, new tubes, idle current, glowing plates?
Both tubes appear to be glowing dull red near the bottom of the plates at the same intensity.
On Mon, Jul 15, 2024, 7:56 PM Louis Parascondola via <Gudguyham= [email protected]> wrote:
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 125–160ma. 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 |
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Re: Ten-Tec Centurion, new tubes, idle current, glowing plates?
Robin,
Attached are the data sheets for a SKP60A 60V Vishay TVS Transorb that I installed from the Centurion Q1 to ground to protect the EBS circuit.
Good luck with your repairs.
73 Bill N4LG
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Re: Ten-Tec Centurion, new tubes, idle current, glowing plates?
Robin,
Here is a problem that may be similar to yours:
,112624.0.html
I had the shorted Q2 problem as well in my Centurion.
73 Bill N4LG
PS: Another problem is a wonky mode switch. I had to make a modification to my Centurion logic to fix a "state" problem. See attached.
Emacs!
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Show quoted text
At 09:37 PM 7/14/2024, Robin Midgett 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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Re: Ten-Tec Centurion, new tubes, idle current, glowing plates?
Especially the carbon comp ones under about 1K, above that, they tend to go high when overloaded. ? ? ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Chuck Neal via groups.io
Sent: Monday, July 15, 2024 10:28 PM
To: [email protected]
Subject: Re: [ham-amplifiers] Ten-Tec Centurion, new tubes, idle current, glowing plates?? Depends on the resistor.? Some go very low in value ? ? Seems to me that a burnt shunt would make the meter read high. 73 – Mike ? Mike B. Feher, N4FS 89 Arnold Blvd. Howell NJ 07731 908-902-3831 ? ? Sounds like two problems at once ? 1) Plate meter is reading low, perhaps due to a burnt shunt resistor in the metering circuit ? AND ? 2) Bias supply is not working depending on the plate voltage in that amp.? Not familiar with that amp’s plate voltage but “zero bias” tubes like 3-500’s do need some minimal bias, like 5 – 8 V negative, again depending upon plate voltage. ? -Chuck K1KW ? ? 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 125–160ma. 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. ? 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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Re: Ten-Tec Centurion, new tubes, idle current, glowing plates?
Depends on the resistor.? Some go very low in value ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Mike Feher
Sent: Monday, July 15, 2024 10:13 PM
To: 'Chuck Neal'; [email protected]
Subject: Re: [ham-amplifiers] Ten-Tec Centurion, new tubes, idle current, glowing plates?? Seems to me that a burnt shunt would make the meter read high. 73 – Mike ? Mike B. Feher, N4FS 89 Arnold Blvd. Howell NJ 07731 908-902-3831 ? ? Sounds like two problems at once ? 1) Plate meter is reading low, perhaps due to a burnt shunt resistor in the metering circuit ? AND ? 2) Bias supply is not working depending on the plate voltage in that amp.? Not familiar with that amp’s plate voltage but “zero bias” tubes like 3-500’s do need some minimal bias, like 5 – 8 V negative, again depending upon plate voltage. ? -Chuck K1KW ? ? 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 125–160ma. 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. ? 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?
Seems to me that a burnt shunt would make the meter read high. 73 – Mike ? Mike B. Feher, N4FS 89 Arnold Blvd. Howell NJ 07731 908-902-3831 ?
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From: [email protected] <[email protected]> On Behalf Of Chuck Neal via groups.io
Sent: Monday, July 15, 2024 9:06 PM
To: [email protected]
Subject: Re: [ham-amplifiers] Ten-Tec Centurion, new tubes, idle current, glowing plates?? Sounds like two problems at once ? 1) Plate meter is reading low, perhaps due to a burnt shunt resistor in the metering circuit ? AND ? 2) Bias supply is not working depending on the plate voltage in that amp.? Not familiar with that amp’s plate voltage but “zero bias” tubes like 3-500’s do need some minimal bias, like 5 – 8 V negative, again depending upon plate voltage. ? -Chuck K1KW ? ? 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 125–160ma. 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. ? 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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Re: Ten-Tec Centurion, new tubes, idle current, glowing plates?
Lou, If you're talking about my photo, i cannot read any brand on it. The photo is from an original AL-80 (no A or B). That tube was in this amp when I bought it in 1994. An ole Timex watch! Bob W4JFA?
On Mon, Jul 15, 2024, 6:36 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?
It takes 5 seconds to test the zener to see if it’s good.
On Monday, July 15, 2024, 9:06 PM, Chuck Neal via groups.io <cdoneal@...> wrote: Sounds like two problems at once ? 1) Plate meter is reading low, perhaps due to a burnt shunt resistor in the metering circuit ? AND ? 2) Bias supply is not working depending on the plate voltage in that amp.? Not familiar with that amp’s plate voltage but “zero bias” tubes like 3-500’s do need some minimal bias, like 5 – 8 V negative, again depending upon plate voltage. ? -Chuck K1KW ? ? 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 125–160ma. 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. ? 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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Re: Ten-Tec Centurion, new tubes, idle current, glowing plates?
If the zener is shorted the idle current goes way higher thsn 125ma. ?So I doubt it’s shorted.
On Monday, July 15, 2024, 9:10 PM, Chuck Neal <cdoneal@...> wrote: That negative bias is sometimes done with a zener in series with the CT od the filament transformer.? When that goes, no negative bias.? I’ve seen that many times, since zeners are not very good in handling higher currents. -Chuck ? ? Sounds like two problems at once ? 1) Plate meter is reading low, perhaps due to a burnt shunt resistor in the metering circuit ? AND ? 2) Bias supply is not working depending on the plate voltage in that amp.? Not familiar with that amp’s plate voltage but “zero bias” tubes like 3-500’s do need some minimal bias, like 5 – 8 V negative, again depending upon plate voltage. ? -Chuck K1KW ? ? 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 125–160ma. 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. ? 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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Re: Ten-Tec Centurion, new tubes, idle current, glowing plates?
That negative bias is sometimes done with a zener in series with the CT od the filament transformer.? When that goes, no negative bias.? I’ve seen that many times, since zeners are not very good in handling higher currents. -Chuck ?
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Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of Chuck Neal via groups.io
Sent: Monday, July 15, 2024 9:06 PM
To: [email protected]
Subject: Re: [ham-amplifiers] Ten-Tec Centurion, new tubes, idle current, glowing plates?? Sounds like two problems at once ? 1) Plate meter is reading low, perhaps due to a burnt shunt resistor in the metering circuit ? AND ? 2) Bias supply is not working depending on the plate voltage in that amp.? Not familiar with that amp’s plate voltage but “zero bias” tubes like 3-500’s do need some minimal bias, like 5 – 8 V negative, again depending upon plate voltage. ? -Chuck K1KW ? ? 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 125–160ma. 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. ? 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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Re: Ten-Tec Centurion, new tubes, idle current, glowing plates?
Sounds like two problems at once ? 1) Plate meter is reading low, perhaps due to a burnt shunt resistor in the metering circuit ? AND ? 2) Bias supply is not working depending on the plate voltage in that amp.? Not familiar with that amp’s plate voltage but “zero bias” tubes like 3-500’s do need some minimal bias, like 5 – 8 V negative, again depending upon plate voltage. ? -Chuck K1KW ?
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Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of Louis Parascondola via groups.io
Sent: Monday, July 15, 2024 8:57 PM
To: [email protected]
Subject: Re: [ham-amplifiers] 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 125–160ma. 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. ? 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?
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 125–160ma. 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 125–160ma. 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 |
|
Bob
Robin Midgett
