Re: Amp Supply LK800 Meter/ALO Board Question
Lower the screen voltage on the radio not the amp to lower the drive to the amp.
All-
It's a grounded grid triode amplifier - three 3CX800A7s.
Many thanks,
-Mark
On Wed, Nov 27, 2024 at 11:22?AM mike repinski via <mikflathead= [email protected]> wrote:
Any chance you could lower the screen voltage? Assuming it's a tetrode or pentode. A string of zeners?
On Wednesday, November 27, 2024 at 09:45:32 AM EST, Omni < selcor@...> wrote:
If you do use an attenuator, which I do here for one of my amps, you will have to find a way to bypass it in receive or you will have 3dB attenuation of the receive signal. ? ? All- Thank you for the information.? I do not recall having a spectacular failure like that, but perhaps the person I loaned the amp to did.? Regardless, it still appears to be working.? Thank you for your help! Regarding manually tuned gear in an automatic station, I fully agree.? My main amp is an Alpha 9500 for that reason, as the antennas and rig are interfaced, and all switching is done whenever I change band on the radio.? This amplifier is being driven by a Swan 350B, which is manual everything - my first radio?that my father bought me when I was a kid.? That brings me to my next question: The?Swan puts out 50-100W, and I need to detune the driver as the only method?for bringing the power down.? Is there a simple mod that will allow this amplifier to accept more power?? If not, then I will buy a 3 dB attenuator to put between the radio and the amplifier (rated for at least 100 W - they're pretty inexpensive).
|
Re: Amp Supply LK800 Meter/ALO Board Question
Pad the input to the final tube? Lot's of ways. Good luck. Listening on 10 on my 50 year old Siltronics 1011C. Memories from High school.?
All-
I'm willing to accept the 3 dB on receive, although it is not great.? I have a separate question?on the Swan forum to see if there?is an easy way to put an RF output adjustment on the radio.? I suspect that will be the easier of the mods to make.
-Mark
If you do use an attenuator, which I do here for one of my amps, you will have to find a way to bypass it in receive or you will have 3dB attenuation of the receive signal. ? ? All- Thank you for the information.? I do not recall having a spectacular failure like that, but perhaps the person I loaned the amp to did.? Regardless, it still appears to be working.? Thank you for your help! Regarding manually tuned gear in an automatic station, I fully agree.? My main amp is an Alpha 9500 for that reason, as the antennas and rig are interfaced, and all switching is done whenever I change band on the radio.? This amplifier is being driven by a Swan 350B, which is manual everything - my first radio?that my father bought me when I was a kid.? That brings me to my next question: The?Swan puts out 50-100W, and I need to detune the driver as the only method?for bringing the power down.? Is there a simple mod that will allow this amplifier to accept more power?? If not, then I will buy a 3 dB attenuator to put between the radio and the amplifier (rated for at least 100 W - they're pretty inexpensive).
|
Re: Amp Supply LK800 Meter/ALO Board Question
All-
It's a grounded grid triode amplifier - three 3CX800A7s.
Many thanks,
-Mark
On Wed, Nov 27, 2024 at 11:22?AM mike repinski via <mikflathead= [email protected]> wrote:
Any chance you could lower the screen voltage? Assuming it's a tetrode or pentode. A string of zeners?
On Wednesday, November 27, 2024 at 09:45:32 AM EST, Omni < selcor@...> wrote:
If you do use an attenuator, which I do here for one of my amps, you will have to find a way to bypass it in receive or you will have 3dB attenuation of the receive signal. ? ? All- Thank you for the information.? I do not recall having a spectacular failure like that, but perhaps the person I loaned the amp to did.? Regardless, it still appears to be working.? Thank you for your help! Regarding manually tuned gear in an automatic station, I fully agree.? My main amp is an Alpha 9500 for that reason, as the antennas and rig are interfaced, and all switching is done whenever I change band on the radio.? This amplifier is being driven by a Swan 350B, which is manual everything - my first radio?that my father bought me when I was a kid.? That brings me to my next question: The?Swan puts out 50-100W, and I need to detune the driver as the only method?for bringing the power down.? Is there a simple mod that will allow this amplifier to accept more power?? If not, then I will buy a 3 dB attenuator to put between the radio and the amplifier (rated for at least 100 W - they're pretty inexpensive).
|
Re: Amp Supply LK800 Meter/ALO Board Question
Any chance you could lower the screen voltage? Assuming it's a tetrode or pentode. A string of zeners?
If you do use an attenuator, which I do here for one of my amps, you will have to find a way to bypass it in receive or you will have 3dB attenuation of the receive signal. ?
From: [email protected] < [email protected]> On Behalf Of Mark KE1IU via groups.io Sent: Wednesday, November 27, 2024 9:23 AM To: [email protected]Subject: Re: [ham-amplifiers] Amp Supply LK800 Meter/ALO Board Question ? All- Thank you for the information.? I do not recall having a spectacular failure like that, but perhaps the person I loaned the amp to did.? Regardless, it still appears to be working.? Thank you for your help! Regarding manually tuned gear in an automatic station, I fully agree.? My main amp is an Alpha 9500 for that reason, as the antennas and rig are interfaced, and all switching is done whenever I change band on the radio.? This amplifier is being driven by a Swan 350B, which is manual everything - my first radio?that my father bought me when I was a kid.? That brings me to my next question: The?Swan puts out 50-100W, and I need to detune the driver as the only method?for bringing the power down.? Is there a simple mod that will allow this amplifier to accept more power?? If not, then I will buy a 3 dB attenuator to put between the radio and the amplifier (rated for at least 100 W - they're pretty inexpensive).
|
Re: Amp Supply LK800 Meter/ALO Board Question
All-
I'm willing to accept the 3 dB on receive, although it is not great.? I have a separate question?on the Swan forum to see if there?is an easy way to put an RF output adjustment on the radio.? I suspect that will be the easier of the mods to make.
-Mark
If you do use an attenuator, which I do here for one of my amps, you will have to find a way to bypass it in receive or you will have 3dB attenuation of the receive signal. ? ? All- Thank you for the information.? I do not recall having a spectacular failure like that, but perhaps the person I loaned the amp to did.? Regardless, it still appears to be working.? Thank you for your help! Regarding manually tuned gear in an automatic station, I fully agree.? My main amp is an Alpha 9500 for that reason, as the antennas and rig are interfaced, and all switching is done whenever I change band on the radio.? This amplifier is being driven by a Swan 350B, which is manual everything - my first radio?that my father bought me when I was a kid.? That brings me to my next question: The?Swan puts out 50-100W, and I need to detune the driver as the only method?for bringing the power down.? Is there a simple mod that will allow this amplifier to accept more power?? If not, then I will buy a 3 dB attenuator to put between the radio and the amplifier (rated for at least 100 W - they're pretty inexpensive).
|
Re: Amp Supply LK800 Meter/ALO Board Question
If you do use an attenuator, which I do here for one of my amps, you will have to find a way to bypass it in receive or you will have 3dB attenuation of the receive signal. ?
toggle quoted message
Show quoted text
From: [email protected] < [email protected]> On Behalf Of Mark KE1IU via groups.io Sent: Wednesday, November 27, 2024 9:23 AM To: [email protected]Subject: Re: [ham-amplifiers] Amp Supply LK800 Meter/ALO Board Question ? All- Thank you for the information.? I do not recall having a spectacular failure like that, but perhaps the person I loaned the amp to did.? Regardless, it still appears to be working.? Thank you for your help! Regarding manually tuned gear in an automatic station, I fully agree.? My main amp is an Alpha 9500 for that reason, as the antennas and rig are interfaced, and all switching is done whenever I change band on the radio.? This amplifier is being driven by a Swan 350B, which is manual everything - my first radio?that my father bought me when I was a kid.? That brings me to my next question: The?Swan puts out 50-100W, and I need to detune the driver as the only method?for bringing the power down.? Is there a simple mod that will allow this amplifier to accept more power?? If not, then I will buy a 3 dB attenuator to put between the radio and the amplifier (rated for at least 100 W - they're pretty inexpensive).
|
Re: Amp Supply LK800 Meter/ALO Board Question
All-
Thank you for the information.? I do not recall having a spectacular failure like that, but perhaps the person I loaned the amp to did.? Regardless, it still appears to be working.? Thank you for your help!
Regarding manually tuned gear in an automatic station, I fully agree.? My main amp is an Alpha 9500 for that reason, as the antennas and rig are interfaced, and all switching is done whenever I change band on the radio.? This amplifier is being driven by a Swan 350B, which is manual everything - my first radio?that my father bought me when I was a kid.? That brings me to my next question: The?Swan puts out 50-100W, and I need to detune the driver as the only method?for bringing the power down.? Is there a simple mod that will allow this amplifier to accept more power?? If not, then I will buy a 3 dB attenuator to put between the radio and the amplifier (rated for at least 100 W - they're pretty inexpensive).
Many thanks,
-Mark
Many thanks,
-Mark
On Wed, Nov 27, 2024 at 8:02?AM Louis Parascondola via <Gudguyham= [email protected]> wrote:
FWIW, I have changed those series resistors on those amps quite a few times before.? They are rather small resistors and are probably sacrificial to save the meter in a fault.? ??
On Tuesday, November 26, 2024, 7:51 PM, Dave w6de <w6de@...> wrote:
Plate/Grid flash over.?
With a manual tune amplifier, a likely suspect is a band change and failure to tune the plate and load at low power.?
Another way is returning to from a break in operation then upon return switching bands or switching antennas without retuning the amp—with Steppir antennas this is an easy mistake to make. Specially when you have automatic antenna selection from your
rig to the antenna switch and/or automatic band selection to the Steppir.
?
The worst thing for a shack is to have a manual operation set-up required in an otherwise fully automatic switching shack from
a modern transceiver.
?
73,
Dave, w6de
?
All-
I gave the amplifier a try tonight at very low drive, slowly working my way up to legal limit to ensure the meter did not peg to the right due to an incorrect resistor value.? Everything seems normal (grid current of ca. 30 mA when tuned,
and turning the load control clockwise reduces it), so that resistor R29 is indeed 18 ohms.? If anyone knows why that might have?blown, I would?be interested in your thoughts.
?
The PDF file here works for me.? I have seen this manual before.? It has no information on the ALO/metering board.? Yes, there are two meters in the schematic, but my LK800a does not have the same wiring of those meters.
?
?
I have an Amp Supply Company LK800A amplifier that puts out full power.? However, I noticed recently that it shows no grid current reading when transmitting on multiple bands.? This is odd behavior, as the grid current normally runs ca.
20-50 mA from my past experience.? I know the meter is fine, because when I turn the meter switch to measure plate voltage, I get the expected reading.? I looked at the meter/ALO board and found that R29 was somewhat charred and had a reading of 180 K ohms.?
No other parts look visibly damaged.
The LK-800 series manual does not have a schematic for this board.? I was able to find one at
.? While the manual is for the LK-400 / LK-500 series, it does have a description of the ALO/Meter board.? The resistor R29 is in the grid current metering circuit and
is claimed to have a value of 18 ohms (p. 27 and 29).? I suspect this is the problem.? The other parts on my board seem to match what is listed on p. 29, and the parts list on p. 29 suggests the board works in the LK-800 series amps because it references the
heavy resistor R30 as being unique to the LK-800 (and is present on my board).
My question - can someone verify that R29 should indeed be 18 ohms?? I would hate for there to be a misprint in the manual and find my grid current meter to be blown when I try this out, as I suspect they are very difficult to obtain.?
Also, do you have any insights as to what would blow this resistor?? A current of 120 mA through that resistor would deliver 0.25 watts...? I have always kept the grid current low, but I did loan the amplifier out a few years ago and don't know if the other
user experienced an issue.
|
Re: Amp Supply LK800 Meter/ALO Board Question
FWIW, I have changed those series resistors on those amps quite a few times before. ?They are rather small resistors and are probably sacrificial to save the meter in a fault.? ??
On Tuesday, November 26, 2024, 7:51 PM, Dave w6de <w6de@...> wrote:
Plate/Grid flash over.?
With a manual tune amplifier, a likely suspect is a band change and failure to tune the plate and load at low power.?
Another way is returning to from a break in operation then upon return switching bands or switching antennas without retuning the amp—with Steppir antennas this is an easy mistake to make. Specially when you have automatic antenna selection from your
rig to the antenna switch and/or automatic band selection to the Steppir.
?
The worst thing for a shack is to have a manual operation set-up required in an otherwise fully automatic switching shack from
a modern transceiver.
?
73,
Dave, w6de
?
All-
I gave the amplifier a try tonight at very low drive, slowly working my way up to legal limit to ensure the meter did not peg to the right due to an incorrect resistor value.? Everything seems normal (grid current of ca. 30 mA when tuned,
and turning the load control clockwise reduces it), so that resistor R29 is indeed 18 ohms.? If anyone knows why that might have?blown, I would?be interested in your thoughts.
?
The PDF file here works for me.? I have seen this manual before.? It has no information on the ALO/metering board.? Yes, there are two meters in the schematic, but my LK800a does not have the same wiring of those meters.
?
?
I have an Amp Supply Company LK800A amplifier that puts out full power.? However, I noticed recently that it shows no grid current reading when transmitting on multiple bands.? This is odd behavior, as the grid current normally runs ca.
20-50 mA from my past experience.? I know the meter is fine, because when I turn the meter switch to measure plate voltage, I get the expected reading.? I looked at the meter/ALO board and found that R29 was somewhat charred and had a reading of 180 K ohms.?
No other parts look visibly damaged.
The LK-800 series manual does not have a schematic for this board.? I was able to find one at
.? While the manual is for the LK-400 / LK-500 series, it does have a description of the ALO/Meter board.? The resistor R29 is in the grid current metering circuit and
is claimed to have a value of 18 ohms (p. 27 and 29).? I suspect this is the problem.? The other parts on my board seem to match what is listed on p. 29, and the parts list on p. 29 suggests the board works in the LK-800 series amps because it references the
heavy resistor R30 as being unique to the LK-800 (and is present on my board).
My question - can someone verify that R29 should indeed be 18 ohms?? I would hate for there to be a misprint in the manual and find my grid current meter to be blown when I try this out, as I suspect they are very difficult to obtain.?
Also, do you have any insights as to what would blow this resistor?? A current of 120 mA through that resistor would deliver 0.25 watts...? I have always kept the grid current low, but I did loan the amplifier out a few years ago and don't know if the other
user experienced an issue.
|
Re: Amp Supply LK800 Meter/ALO Board Question
Plate/Grid flash over.?
With a manual tune amplifier, a likely suspect is a band change and failure to tune the plate and load at low power.?
Another way is returning to from a break in operation then upon return switching bands or switching antennas without retuning the amp—with Steppir antennas this is an easy mistake to make. Specially when you have automatic antenna selection from your
rig to the antenna switch and/or automatic band selection to the Steppir.
?
The worst thing for a shack is to have a manual operation set-up required in an otherwise fully automatic switching shack from
a modern transceiver.
?
73,
Dave, w6de
toggle quoted message
Show quoted text
From: [email protected] <[email protected]>
On Behalf Of Mark KE1IU via groups.io
Sent: 26 November, 2024 23:24
To: [email protected]
Subject: Re: [ham-amplifiers] Amp Supply LK800 Meter/ALO Board Question
?
All-
I gave the amplifier a try tonight at very low drive, slowly working my way up to legal limit to ensure the meter did not peg to the right due to an incorrect resistor value.? Everything seems normal (grid current of ca. 30 mA when tuned,
and turning the load control clockwise reduces it), so that resistor R29 is indeed 18 ohms.? If anyone knows why that might have?blown, I would?be interested in your thoughts.
?
The PDF file here works for me.? I have seen this manual before.? It has no information on the ALO/metering board.? Yes, there are two meters in the schematic, but my LK800a does not have the same wiring of those meters.
?
?
I have an Amp Supply Company LK800A amplifier that puts out full power.? However, I noticed recently that it shows no grid current reading when transmitting on multiple bands.? This is odd behavior, as the grid current normally runs ca.
20-50 mA from my past experience.? I know the meter is fine, because when I turn the meter switch to measure plate voltage, I get the expected reading.? I looked at the meter/ALO board and found that R29 was somewhat charred and had a reading of 180 K ohms.?
No other parts look visibly damaged.
The LK-800 series manual does not have a schematic for this board.? I was able to find one at
.? While the manual is for the LK-400 / LK-500 series, it does have a description of the ALO/Meter board.? The resistor R29 is in the grid current metering circuit and
is claimed to have a value of 18 ohms (p. 27 and 29).? I suspect this is the problem.? The other parts on my board seem to match what is listed on p. 29, and the parts list on p. 29 suggests the board works in the LK-800 series amps because it references the
heavy resistor R30 as being unique to the LK-800 (and is present on my board).
My question - can someone verify that R29 should indeed be 18 ohms?? I would hate for there to be a misprint in the manual and find my grid current meter to be blown when I try this out, as I suspect they are very difficult to obtain.?
Also, do you have any insights as to what would blow this resistor?? A current of 120 mA through that resistor would deliver 0.25 watts...? I have always kept the grid current low, but I did loan the amplifier out a few years ago and don't know if the other
user experienced an issue.
|
Re: Amp Supply LK800 Meter/ALO Board Question
All-
I gave the amplifier a try tonight at very low drive, slowly working my way up to legal limit to ensure the meter did not peg to the right due to an incorrect resistor value.? Everything seems normal (grid current of ca. 30 mA when tuned, and turning the load control clockwise reduces it), so that resistor R29 is indeed 18 ohms.? If anyone knows why that might have?blown, I would?be interested in your thoughts.
Many thanks,
-Mark
All-
The PDF file here works for me.? I have seen this manual before.? It has no information on the ALO/metering board.? Yes, there are two meters in the schematic, but my LK800a does not have the same wiring of those meters.
Many thanks,
-Mark
All-
?
I have an Amp Supply Company LK800A amplifier that puts out full power.? However, I noticed recently that it shows no grid current reading when transmitting on multiple bands.? This is odd behavior, as the grid current normally runs ca. 20-50 mA from my past experience.? I know the meter is fine, because when I turn the meter switch to measure plate voltage, I get the expected reading.? I looked at the meter/ALO board and found that R29 was somewhat charred and had a reading of 180 K ohms.? No other parts look visibly damaged.
?
The LK-800 series manual does not have a schematic for this board.? I was able to find one at .? While the manual is for the LK-400 / LK-500 series, it does have a description of the ALO/Meter board.? The resistor R29 is in the grid current metering circuit and is claimed to have a value of 18 ohms (p. 27 and 29).? I suspect this is the problem.? The other parts on my board seem to match what is listed on p. 29, and the parts list on p. 29 suggests the board works in the LK-800 series amps because it references the heavy resistor R30 as being unique to the LK-800 (and is present on my board).
?
My question - can someone verify that R29 should indeed be 18 ohms?? I would hate for there to be a misprint in the manual and find my grid current meter to be blown when I try this out, as I suspect they are very difficult to obtain.? Also, do you have any insights as to what would blow this resistor?? A current of 120 mA through that resistor would deliver 0.25 watts...? I have always kept the grid current low, but I did loan the amplifier out a few years ago and don't know if the other user experienced an issue.
?
Many thanks,
?
-Mark
|
Re: Amp Supply LK800 Meter/ALO Board Question
All-
The PDF file here works for me.? I have seen this manual before.? It has no information on the ALO/metering board.? Yes, there are two meters in the schematic, but my LK800a does not have the same wiring of those meters.
Many thanks,
-Mark
All-
?
I have an Amp Supply Company LK800A amplifier that puts out full power.? However, I noticed recently that it shows no grid current reading when transmitting on multiple bands.? This is odd behavior, as the grid current normally runs ca. 20-50 mA from my past experience.? I know the meter is fine, because when I turn the meter switch to measure plate voltage, I get the expected reading.? I looked at the meter/ALO board and found that R29 was somewhat charred and had a reading of 180 K ohms.? No other parts look visibly damaged.
?
The LK-800 series manual does not have a schematic for this board.? I was able to find one at .? While the manual is for the LK-400 / LK-500 series, it does have a description of the ALO/Meter board.? The resistor R29 is in the grid current metering circuit and is claimed to have a value of 18 ohms (p. 27 and 29).? I suspect this is the problem.? The other parts on my board seem to match what is listed on p. 29, and the parts list on p. 29 suggests the board works in the LK-800 series amps because it references the heavy resistor R30 as being unique to the LK-800 (and is present on my board).
?
My question - can someone verify that R29 should indeed be 18 ohms?? I would hate for there to be a misprint in the manual and find my grid current meter to be blown when I try this out, as I suspect they are very difficult to obtain.? Also, do you have any insights as to what would blow this resistor?? A current of 120 mA through that resistor would deliver 0.25 watts...? I have always kept the grid current low, but I did loan the amplifier out a few years ago and don't know if the other user experienced an issue.
?
Many thanks,
?
-Mark
|
Re: Amp Supply LK800 Meter/ALO Board Question
Mark- The link to the LK800 manual didn't work here, error says page no longer exists. Can you check to make sure it's displayed correctly in your post- some of us would like to? obtain that manual. Thanks!
Tom K0SN
All-
?
I have an Amp Supply Company LK800A amplifier that puts out full power.? However, I noticed recently that it shows no grid current reading when transmitting on multiple bands.? This is odd behavior, as the grid current normally runs ca. 20-50 mA from my past experience.? I know the meter is fine, because when I turn the meter switch to measure plate voltage, I get the expected reading.? I looked at the meter/ALO board and found that R29 was somewhat charred and had a reading of 180 K ohms.? No other parts look visibly damaged.
?
The LK-800 series manual does not have a schematic for this board.? I was able to find one at .? While the manual is for the LK-400 / LK-500 series, it does have a description of the ALO/Meter board.? The resistor R29 is in the grid current metering circuit and is claimed to have a value of 18 ohms (p. 27 and 29).? I suspect this is the problem.? The other parts on my board seem to match what is listed on p. 29, and the parts list on p. 29 suggests the board works in the LK-800 series amps because it references the heavy resistor R30 as being unique to the LK-800 (and is present on my board).
?
My question - can someone verify that R29 should indeed be 18 ohms?? I would hate for there to be a misprint in the manual and find my grid current meter to be blown when I try this out, as I suspect they are very difficult to obtain.? Also, do you have any insights as to what would blow this resistor?? A current of 120 mA through that resistor would deliver 0.25 watts...? I have always kept the grid current low, but I did loan the amplifier out a few years ago and don't know if the other user experienced an issue.
?
Many thanks,
?
-Mark
|
Re: Amp Supply LK800 Meter/ALO Board Question
toggle quoted message
Show quoted text
All-
?
I have an Amp Supply Company LK800A amplifier that puts out full power.? However, I noticed recently that it shows no grid current reading when transmitting on multiple bands.? This is odd behavior, as the grid current normally runs ca. 20-50 mA from my past experience.? I know the meter is fine, because when I turn the meter switch to measure plate voltage, I get the expected reading.? I looked at the meter/ALO board and found that R29 was somewhat charred and had a reading of 180 K ohms.? No other parts look visibly damaged.
?
The LK-800 series manual does not have a schematic for this board.? I was able to find one at .? While the manual is for the LK-400 / LK-500 series, it does have a description of the ALO/Meter board.? The resistor R29 is in the grid current metering circuit and is claimed to have a value of 18 ohms (p. 27 and 29).? I suspect this is the problem.? The other parts on my board seem to match what is listed on p. 29, and the parts list on p. 29 suggests the board works in the LK-800 series amps because it references the heavy resistor R30 as being unique to the LK-800 (and is present on my board).
?
My question - can someone verify that R29 should indeed be 18 ohms?? I would hate for there to be a misprint in the manual and find my grid current meter to be blown when I try this out, as I suspect they are very difficult to obtain.? Also, do you have any insights as to what would blow this resistor?? A current of 120 mA through that resistor would deliver 0.25 watts...? I have always kept the grid current low, but I did loan the amplifier out a few years ago and don't know if the other user experienced an issue.
?
Many thanks,
?
-Mark
|
No, other than the one you showed which I already had.?
|
Amp Supply LK800 Meter/ALO Board Question
All-
?
I have an Amp Supply Company LK800A amplifier that puts out full power.? However, I noticed recently that it shows no grid current reading when transmitting on multiple bands.? This is odd behavior, as the grid current normally runs ca. 20-50 mA from my past experience.? I know the meter is fine, because when I turn the meter switch to measure plate voltage, I get the expected reading.? I looked at the meter/ALO board and found that R29 was somewhat charred and had a reading of 180 K ohms.? No other parts look visibly damaged.
?
The LK-800 series manual does not have a schematic for this board.? I was able to find one at .? While the manual is for the LK-400 / LK-500 series, it does have a description of the ALO/Meter board.? The resistor R29 is in the grid current metering circuit and is claimed to have a value of 18 ohms (p. 27 and 29).? I suspect this is the problem.? The other parts on my board seem to match what is listed on p. 29, and the parts list on p. 29 suggests the board works in the LK-800 series amps because it references the heavy resistor R30 as being unique to the LK-800 (and is present on my board).
?
My question - can someone verify that R29 should indeed be 18 ohms?? I would hate for there to be a misprint in the manual and find my grid current meter to be blown when I try this out, as I suspect they are very difficult to obtain.? Also, do you have any insights as to what would blow this resistor?? A current of 120 mA through that resistor would deliver 0.25 watts...? I have always kept the grid current low, but I did loan the amplifier out a few years ago and don't know if the other user experienced an issue.
?
Many thanks,
?
-Mark
|
?
?
Red 7mm solid copper core spark plug ignition wire sold by the foot Made in USA
?
US $1.58/FT
?
This wire also comes in other colors.
?
I have not used this particular wire so I cannot rate it.? But “most” sparkplug wire is rated at (+,-) 40KV and some much higher.? One could call Ton’s Performance
and verify the voltage rating.
The wire would also have to stand up to rapid pulses.
?
I have a roll of similar wire I use in refurbishing SB-220 and other similar amps as well as my two Henry #K premier amps. The henry’s run ~4600 Vdc in the SSB
position.
?
Maybe this helps, maybe not.
?
Walter
KR4HV
?
|
Re: Smoker contamination removal
Its you Joe. They work for me
C
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Show quoted text
Those links you posted are inop.? You might want to just insert those images into you post or attach them to your post.
Joe - W7RKN
-----Original Message-----
From: [email protected] [ mailto:[email protected]] On Behalf Of Technotronic Dimensions via
Subject: Re: [ham-amplifiers] Smoker contamination removal
I got the front cntrol panel all done, getting into the PS
area now...pretty bad.
In the PA compartment I see the bread slicers have some stuck in there,
should be fun
getting that out. Hopefully I can just let it soak in the stuff sprayed on,
then maybe some compressed air can blow them clean, but for now
this area is next.
|
Re: Smoker contamination removal
Those links you posted are inop. You might want to just insert those images into you post or attach them to your post.
Joe - W7RKN
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-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of Technotronic Dimensions via groups.io Subject: Re: [ham-amplifiers] Smoker contamination removal I got the front cntrol panel all done, getting into the PS area now...pretty bad. In the PA compartment I see the bread slicers have some stuck in there, should be fun getting that out. Hopefully I can just let it soak in the stuff sprayed on, then maybe some compressed air can blow them clean, but for now this area is next.
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Years ago I built a supply for a L4B amp. Someone on Ebay was selling the cables that Drake used. It has control wires plus the high voltage cable in one sheath. Mike
Using spark plug wire sounds clever but any spec I found for it shows "spiral wound" or "copper alloy" conductors rated in ohms per foot.? So even seeming "solid core" wires are intentionally providing some kind of resistance or impedance for that application.? What I was hoping for is a specific wire folks have seen used in existing designs, e.g. Belden XXXX implying it was qualified or at least used with some success for this application.? The Drake amp has a separate power supply - what does it use for HV?? What do contemporary amps use in their HV supply, even for short interconnects?
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Mark K5LXP
Albuquerque, NM
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Bob