Re: Parts inventory question...
Try KE9PQ I think its Nationwide radio out of Wisconsin.
Not everything but a lot.
73 Tim WB8UHZ
On Tuesday, April 27, 2021, 1:26:24 AM EDT, Patrick P <sbus1313@...> wrote:
Gents,
? I’ve got quite a collection of older rigs that will need new caps and probably a lot of other components to refresh. I’ve been visualizing coming up with a parts list for each rig but then got to thinking, is there somewhere that has a ready made pre-assembled parts bin I could buy to populate my little “shop” with a decent inventory of common parts? ?Versus hitting Mouser with a giant grocery list?
? I have Drake, Collins, Heathkit, Ten-Tec, Yaesu, Icom, and Kenwood. Pretty much a lifelong collection that I’d like to keep in good working order as long as possible.?
Regards,
Patrick
NG7I
|
Parts inventory question...
Gents,
? I’ve got quite a collection of older rigs that will need new caps and probably a lot of other components to refresh. I’ve been visualizing coming up with a parts list for each rig but then got to thinking, is there somewhere that has a ready made pre-assembled parts bin I could buy to populate my little “shop” with a decent inventory of common parts? ?Versus hitting Mouser with a giant grocery list?
? I have Drake, Collins, Heathkit, Ten-Tec, Yaesu, Icom, and Kenwood. Pretty much a lifelong collection that I’d like to keep in good working order as long as possible.?
Regards,
Patrick
NG7I
|
Can somebody tell me what I should see at pin1 / V2 6hs6 with a scope ?? I'm good at the cathode with 1.8PP signal from v8 the premixer.? I do not have 5.645 out of V2 , its just the cathode freq at a lower level.? I'm not experienced but learning my way, any help appreciated.? -Ron K0IDX
|
Re: Drake L75 - Plate variable capacitor damage found
Random thoughts... You can try Oleic acid as a deoxit D100 equivalent. Internet lore suggests that it was the main ingredient in the original DeOxit and there is some evidence to back this up. It should be easier to get as it is a monounsaturated omega-9 fatty acid found in hature and used in food processing, and there are no associated hazards or tactical applications. I've thought about mounting a small webcam style of camera on the wall behind the L7 strategically placed to look in through the fan. Never got to try it while I had my L7 hooked up. Gary said "condenser". Hee-hee. Showing his age. :) Me too. When I was a kid they were still called that often as not. 73 -Jim NU0C On Mon, 26 Apr 2021 18:12:45 +0000 (UTC) "Roberto - YS1RS via groups.io" <ys1rs@...> wrote: Hi hi, none of the "Dopes" at least for electronics are available here in YS. We don't even have Deoxit. There is no market for those here, so... no commercial value to bring those here for sellers/distributors. It is a "problem" as those chemicals require special importation permits for only a handful of Hams in the country.
On the other side... my amp sits, not on a desk but in a reduced space (rack) which makes difficult to have a "peek" on the tube. Ham shack is minimal 2.5 x 2 meters... around 16 square ft.
With all the care in the world will have to defeat interlocks (again) and be extremely careful when testing for the required "cooking color". Has personal learning value for me so, will have to plan for that classroom/laboratory session. The amp is heavy for a reduced space maneuverability. I can imagine a big L7/L4 will be even heavier. I was wondering how you do to move around with those big species.
Will push the tube to its rated values as per technical publication but, a little less to be safe and compare with the meter readings. Will obtain the required values for safe good operation compared to the proven tuning methods you shared we me earlier (not by the amp instructions that belonged to a time where input level was used and not output level as of today).Will be nice to see how the tuning approaches to the best performance of the tube and see its colors in action versus meter reading not reaching maximum as per original technical publication for the Eimac tube.
73RobYS1RS
On Monday, April 26, 2021, 11:43:51 AM CST, Gary Follett <xntrick1948@...> wrote:
I have piles of replacement plate for the air variables. They are easy to change and end up with the finished condenser being the equivalent of a new one.
Gary
W0DVN
PS: Sorry for my diversion about CORONA DOPE, though it is useful to know that this works on transformers!
On Apr 26, 2021, at 8:46 AM, Joe WB9SBD <nss@...> wrote:
Mirror?
On 4/26/2021 8:41 AM, amfone via groups.io wrote:
If the L75 is like the L7 of which I have two you can get a peek at the 3-500Z color by looking through the fan on the back of the amp, yes you do have to get to the back of the amp but you can take a look.
73 Tim
WB8UHZ
On Monday, April 26, 2021, 12:28:29 AM EDT, Roberto - YS1RS via groups.io <ys1rs@...> wrote:
Yes, understood about the little red running of the tube... not sherry red of course. Only problem is that the amp is enclosed in a chassis with interlocks... otherwise there is no way to keep a visual on the tube... Yes, this can be done by instruments by following the technical data of the tube. This is my next step in my learning journey.
Still looking for a brand new tube though this one is working but, under the condition I found this amp, I can see has been abused by the damage on the plates of the variable cap.?
YS1RS
On Apr 25, 2021, at 22:02, Ron Magnus <ron.magnus@...> wrote:
I'll jump in here as well on how hard these tubes need to be run to keep them happy;
I ran a Bauer 707 AM transmitter many years ago while in Korea at an AFKN station.? That transmitter used 4-400 tubes for RF out and for the modulator.? The plates on the finals stayed red all the time and they were happy.? I believe if my memory is correct the modulator tubes did the same.? I bring this up as the 4-400 and the 3-500 are somewhat the same in this characteristic.
Ron wa7gfe
As others mentioned the 3-500 tubes need to be ran hard some of the time as the plate absorbs the small amount of gas in the tube when red.? Just don't over load the tube.?
Ralph ku4pt
|
Re: New to Drake and ham radio
Welcome, Steve, and best of luck to you!? Most important thing is to buy a copy of Garey Barrell's (K4OAH SK) service CD.? Garey's family is still operating the web site at
Eric
WK3B
|
Re: Drake L75 - Plate variable capacitor damage found
Nobody making L-75 HV kits that I’ve heard about, though Mike at The Heathkit Shop was looking at it about a year ago. Turns out there are at least two different board styles which complicates things, especially given how few are out there. ?It’s easier to just buy the caps and replace them and the diodes/resistors. That’s what I did with mine years ago.
73 Peter
toggle quoted message
Show quoted text
On Apr 26, 2021, at 3:42 PM, boat599 < wctaylor@...> wrote: While you’re the subject of the L75, does anyone know of replacement high voltage circuit boards or re-cap kits? I looked on the usual sites but no luck.
I bought one off Ebay over a year ago knowing that it had a problem (seller made full disclosure). It was shipped in two boxes, amp and tube well packed in one, power transformer in the other.
The caps are obviously bad due to bulging on the positive end. I haven’t put it together yet but looking at repair parts before I start.
Thanks, Bill? KD4LXC? ? That was great stuff. You take a flyback that was screaming at you and stinking up the place and give it 5 more years of life, saving the customer maybe $100!?
Gary
W0DVN
Thanks Gary, that's what I was thinking of.?? DOPE! :-)
John K5MO The thing you need for arc suppression is CORONA DOPE, not Q-DOPE.
CORONA DOPE is so effective it worked well on TV flyback transformers to 30 KV.
Gary W0DVN
I'll jump in here as well on how hard these tubes need to be run to keep them happy;
I ran a Bauer 707 AM transmitter many years ago while in Korea at an AFKN station.? That transmitter used 4-400 tubes for RF out and for the modulator.? The plates on the finals stayed red all the time and they were happy.? I believe if my memory is correct the modulator tubes did the same.? I bring this up as the 4-400 and the 3-500 are somewhat the same in this characteristic.
Ron wa7gfe
As others mentioned the 3-500 tubes need to be ran hard
some of the time as the plate absorbs the small amount of gas in the
tube when red.? Just don't over load the tube.?
Ralph ku4pt
|
Re: Drake L75 - Plate variable capacitor damage found
While you’re the subject of the L75, does anyone know of replacement high voltage circuit boards or re-cap kits? I looked on the usual sites but no luck.
I bought one off Ebay over a year ago knowing that it had a problem (seller made full disclosure). It was shipped in two boxes, amp and tube well packed in one, power transformer in the other.
The caps are obviously bad due to bulging on the positive end. I haven’t put it together yet but looking at repair parts before I start.
Thanks, Bill?
toggle quoted message
Show quoted text
On Apr 26, 2021, at 5:28 PM, Gary Follett <xntrick1948@...> wrote:
? That was great stuff. You take a flyback that was screaming at you and stinking up the place and give it 5 more years of life, saving the customer maybe $100!?
Gary
W0DVN
Thanks Gary, that's what I was thinking of.?? DOPE! :-)
John K5MO The thing you need for arc suppression is CORONA DOPE, not Q-DOPE.
CORONA DOPE is so effective it worked well on TV flyback transformers to 30 KV.
Gary W0DVN
I'll jump in here as well on how hard these tubes need to be run to keep them happy;
I ran a Bauer 707 AM transmitter many years ago while in Korea at an AFKN station.? That transmitter used 4-400 tubes for RF out and for the modulator.? The plates on the finals stayed red all the time and they were happy.? I believe if my memory is correct the modulator tubes did the same.? I bring this up as the 4-400 and the 3-500 are somewhat the same in this characteristic.
Ron wa7gfe
As others mentioned the 3-500 tubes need to be ran hard
some of the time as the plate absorbs the small amount of gas in the
tube when red.? Just don't over load the tube.?
Ralph ku4pt
|
Re: Drake L75 - Plate variable capacitor damage found
That was great stuff. You take a flyback that was screaming at you and stinking up the place and give it 5 more years of life, saving the customer maybe $100!?
Gary
toggle quoted message
Show quoted text
Thanks Gary, that's what I was thinking of.?? DOPE! :-)
John K5MO The thing you need for arc suppression is CORONA DOPE, not Q-DOPE.
CORONA DOPE is so effective it worked well on TV flyback transformers to 30 KV.
Gary W0DVN
I'll jump in here as well on how hard these tubes need to be run to keep them happy;
I ran a Bauer 707 AM transmitter many years ago while in Korea at an AFKN station.? That transmitter used 4-400 tubes for RF out and for the modulator.? The plates on the finals stayed red all the time and they were happy.? I believe if my memory is correct the modulator tubes did the same.? I bring this up as the 4-400 and the 3-500 are somewhat the same in this characteristic.
Ron wa7gfe
As others mentioned the 3-500 tubes need to be ran hard
some of the time as the plate absorbs the small amount of gas in the
tube when red.? Just don't over load the tube.?
Ralph ku4pt
|
Re: Drake L75 - Plate variable capacitor damage found
Thanks Gary, that's what I was thinking of.?? DOPE! :-)
John K5MO
The thing you need for arc suppression is CORONA DOPE, not Q-DOPE.
CORONA DOPE is so effective it worked well on TV flyback transformers to 30 KV.
Gary W0DVN
I'll jump in here as well on how hard these tubes need to be run to keep them happy;
I ran a Bauer 707 AM transmitter many years ago while in Korea at an AFKN station.? That transmitter used 4-400 tubes for RF out and for the modulator.? The plates on the finals stayed red all the time and they were happy.? I believe if my memory is correct the modulator tubes did the same.? I bring this up as the 4-400 and the 3-500 are somewhat the same in this characteristic.
Ron wa7gfe
As others mentioned the 3-500 tubes need to be ran hard
some of the time as the plate absorbs the small amount of gas in the
tube when red.? Just don't over load the tube.?
Ralph ku4pt
|
Re: Drake L75 - Plate variable capacitor damage found
You are correct, I was confusing it with something else. See:
<>
toggle quoted message
Show quoted text
On 4/26/2021 1:00 PM, Vince Vielhaber wrote:
On 04/26/2021 02:41 PM, Richard Knoppow wrote:
?? I think corona dope has a something conductive in it. Conductive??? Wouldn't that defeat it's purpose?
Vince.
--
Richard Knoppow
1oldlens1@...
WB6KBL
|
Re: Drake L75 - Plate variable capacitor damage found
On 04/26/2021 02:41 PM, Richard Knoppow wrote: I think corona dope has a something conductive in it. Conductive? Wouldn't that defeat it's purpose? Vince. -- K8ZW
|
Re: Drake L75 - Plate variable capacitor damage found
I don't know for certain what is in corona dope but making Q-dope is easy. I make it from styrofoam cups by dissolving them in MEK. However, you can also use other solvents. Any white styrofoam will do. It dissolves quickly at first but may take a couple of days to get enough for the dope to be fairly thick. I make it so its about as thick as honey. If it thickens with time you can thin it with the same solvent. I tested my home made dope using a Boonton Q-meter by winding some air wound coils and then coating them. The dope did not change the measured Q. I use it in various ways particularly to fasten coils on some old equipment that used it for adjustment of inductance. An example is the Hewlett-Packard 606A signal generator. In any case, its easy to make and cheap.
?? I think corona dope has a something conductive in it.
toggle quoted message
Show quoted text
On 4/26/2021 11:12 AM, Roberto - YS1RS via groups.io wrote: Hi hi, none of the "Dopes" at least for electronics are available here in YS. We don't even have Deoxit. There is no market for those here, so... no commercial value to bring those here for sellers/distributors. It is a "problem" as those chemicals require special importation permits for only a handful of Hams in the country.
On the other side... my amp sits, not on a desk but in a reduced space (rack) which makes difficult to have a "peek" on the tube. Ham shack is minimal 2.5 x 2 meters... around 16 square ft.
With all the care in the world will have to defeat interlocks (again) and be extremely careful when testing for the required "cooking color". Has personal learning value for me so, will have to plan for that classroom/laboratory session. The amp is heavy for a reduced space maneuverability. I can imagine a big L7/L4 will be even heavier. I was wondering how you do to move around with those big species.
Will push the tube to its rated values as per technical publication but, a little less to be safe and compare with the meter readings. Will obtain the required values for safe good operation compared to the proven tuning methods you shared we me earlier (not by the amp instructions that belonged to a time where input level was used and not output level as of today).Will be nice to see how the tuning approaches to the best performance of the tube and see its colors in action versus meter reading not reaching maximum as per original technical publication for the Eimac tube.
73
Rob
YS1RS
On Monday, April 26, 2021, 11:43:51 AM CST, Gary Follett <xntrick1948@...> wrote:
I have piles of replacement plate for the air variables. They are easy to change and end up with the finished condenser being the equivalent of a new one.
Gary
W0DVN
PS: Sorry for my diversion about CORONA DOPE, though it is useful to know that this works on transformers!
On Apr 26, 2021, at 8:46 AM, Joe WB9SBD <nss@... <mailto:nss@...>> wrote:
Mirror?
On 4/26/2021 8:41 AM, amfone via groups.io <> wrote:
If the L75 is like the L7 of which I have two you can get a peek at the 3-500Z color by looking through the fan on the back of the amp, yes you do have to get to the back of the amp but you can take a look.
73 Tim
WB8UHZ
On Monday, April 26, 2021, 12:28:29 AM EDT, Roberto - YS1RS via groups.io <> <ys1rs@...> <mailto:ys1rs@...> wrote:
Yes, understood about the little red running of the tube... not sherry red of course.
Only problem is that the amp is enclosed in a chassis with interlocks... otherwise there is no way to keep a visual on the tube... Yes, this can be done by instruments by following the technical data of the tube. This is my next step in my learning journey.
Still looking for a brand new tube though this one is working but, under the condition I found this amp, I can see has been abused by the damage on the plates of the variable cap.
YS1RS
On Apr 25, 2021, at 22:02, Ron Magnus <ron.magnus@... <mailto:ron.magnus@...>> wrote:
I'll jump in here as well on how hard these tubes need to be run to keep them happy;
I ran a Bauer 707 AM transmitter many years ago while in Korea at an AFKN station. That transmitter used 4-400 tubes for RF out and for the modulator.? The plates on the finals stayed red all the time and they were happy.? I believe if my memory is correct the modulator tubes did the same.? I bring this up as the 4-400 and the 3-500 are somewhat the same in this characteristic.
Ron wa7gfe
As others mentioned the 3-500 tubes need to be ran hard some of the time as the plate absorbs the small amount of gas in the tube when red. Just don't over load the tube.
Ralph ku4pt
--
Richard Knoppow
1oldlens1@...
WB6KBL
|
Re: Drake L75 - Plate variable capacitor damage found
The 'good thing' about the L4 is it is in 2 pieces .? The main amp section and the high voltage power supply.? There is about a 6 foot power cable between the 2 pieces.? Fastened on the power supply end and a multiconductor plug on the amplifier end.
Ralph ku4pt
On Monday, April 26, 2021, 02:12:56 PM EDT, Roberto - YS1RS via groups.io <ys1rs@...> wrote:
On the other side... my amp sits, not on a desk but in a reduced space (rack) which makes difficult to have a "peek" on the tube. Ham shack is minimal 2.5 x 2 meters... around 16 square ft.
With all the care in the world will have to defeat interlocks (again) and be extremely careful when testing for the required "cooking color". Has personal learning value for me so, will have to plan for that classroom/laboratory session. The amp is heavy for a reduced space maneuverability. I can imagine a big L7/L4 will be even heavier. I was wondering how you do to move around with those big species.
_,_
|
Re: Drake L75 - Plate variable capacitor damage found
Hi hi, none of the "Dopes" at least for electronics are available here in YS. We don't even have Deoxit. There is no market for those here, so... no commercial value to bring those here for sellers/distributors. It is a "problem" as those chemicals require special importation permits for only a handful of Hams in the country.
On the other side... my amp sits, not on a desk but in a reduced space (rack) which makes difficult to have a "peek" on the tube. Ham shack is minimal 2.5 x 2 meters... around 16 square ft.
With all the care in the world will have to defeat interlocks (again) and be extremely careful when testing for the required "cooking color". Has personal learning value for me so, will have to plan for that classroom/laboratory session. The amp is heavy for a reduced space maneuverability. I can imagine a big L7/L4 will be even heavier. I was wondering how you do to move around with those big species.
Will push the tube to its rated values as per technical publication but, a little less to be safe and compare with the meter readings. Will obtain the required values for safe good operation compared to the proven tuning methods you shared we me earlier (not by the amp instructions that belonged to a time where input level was used and not output level as of today).Will be nice to see how the tuning approaches to the best performance of the tube and see its colors in action versus meter reading not reaching maximum as per original technical publication for the Eimac tube.
73 Rob YS1RS
On Monday, April 26, 2021, 11:43:51 AM CST, Gary Follett <xntrick1948@...> wrote:
I have piles of replacement plate for the air variables. They are easy to change and end up with the finished condenser being the equivalent of a new one.
Gary
W0DVN
PS: Sorry for my diversion about CORONA DOPE, though it is useful to know that this works on transformers! On Apr 26, 2021, at 8:46 AM, Joe WB9SBD < nss@...> wrote:
Mirror?
On 4/26/2021 8:41 AM, amfone via
wrote:
If the L75 is like the L7 of
which I have two you can get a peek at the 3-500Z color by
looking through the fan on the back of the amp, yes you do
have to get to the back of the amp but you can take a look.
73 Tim
WB8UHZ
On Monday, April 26, 2021, 12:28:29 AM EDT, Roberto -
YS1RS via <ys1rs@...> wrote:
Yes, understood about the little red running of the
tube... not sherry red of course.
Only problem is that the amp is enclosed in a
chassis with interlocks... otherwise there is no way
to keep a visual on the tube... Yes, this can be done
by instruments by following the technical data of the
tube. This is my next step in my learning journey.
Still looking for a brand new tube though this one
is working but, under the condition I found this amp,
I can see has been abused by the damage on the plates
of the variable cap.?
YS1RS
I'll jump in here as well on how hard these
tubes need to be run to keep them happy;
I ran a Bauer 707 AM transmitter many years
ago while in Korea at an AFKN station.? That
transmitter used 4-400 tubes for RF out and for
the modulator.? The plates on the finals stayed
red all the time and they were happy.? I believe
if my memory is correct the modulator tubes did
the same.? I bring this up as the 4-400 and the
3-500 are somewhat the same in this
characteristic.
Ron wa7gfe
As others mentioned the 3-500
tubes need to be ran hard some of the time as
the plate absorbs the small amount of gas in
the tube when red.? Just don't over load the
tube.?
Ralph ku4pt
|
Re: Drake L75 - Plate variable capacitor damage found
I have piles of replacement plate for the air variables. They are easy to change and end up with the finished condenser being the equivalent of a new one.
Gary
W0DVN
PS: Sorry for my diversion about CORONA DOPE, though it is useful to know that this works on transformers!
toggle quoted message
Show quoted text
On Apr 26, 2021, at 8:46 AM, Joe WB9SBD < nss@...> wrote:
Mirror?
On 4/26/2021 8:41 AM, amfone via
wrote:
If the L75 is like the L7 of
which I have two you can get a peek at the 3-500Z color by
looking through the fan on the back of the amp, yes you do
have to get to the back of the amp but you can take a look.
73 Tim
WB8UHZ
On Monday, April 26, 2021, 12:28:29 AM EDT, Roberto -
YS1RS via <ys1rs@...> wrote:
Yes, understood about the little red running of the
tube... not sherry red of course.
Only problem is that the amp is enclosed in a
chassis with interlocks... otherwise there is no way
to keep a visual on the tube... Yes, this can be done
by instruments by following the technical data of the
tube. This is my next step in my learning journey.
Still looking for a brand new tube though this one
is working but, under the condition I found this amp,
I can see has been abused by the damage on the plates
of the variable cap.?
YS1RS
I'll jump in here as well on how hard these
tubes need to be run to keep them happy;
I ran a Bauer 707 AM transmitter many years
ago while in Korea at an AFKN station.? That
transmitter used 4-400 tubes for RF out and for
the modulator.? The plates on the finals stayed
red all the time and they were happy.? I believe
if my memory is correct the modulator tubes did
the same.? I bring this up as the 4-400 and the
3-500 are somewhat the same in this
characteristic.
Ron wa7gfe
As others mentioned the 3-500
tubes need to be ran hard some of the time as
the plate absorbs the small amount of gas in
the tube when red.? Just don't over load the
tube.?
Ralph ku4pt
|
Re: Drake L75 - Plate variable capacitor damage found
The thing you need for arc suppression is CORONA DOPE, not Q-DOPE.
CORONA DOPE is so effective it worked well on TV flyback transformers to 30 KV.
Gary
toggle quoted message
Show quoted text
I'll jump in here as well on how hard these tubes need to be run to keep them happy;
I ran a Bauer 707 AM transmitter many years ago while in Korea at an AFKN station.? That transmitter used 4-400 tubes for RF out and for the modulator.? The plates on the finals stayed red all the time and they were happy.? I believe if my memory is correct the modulator tubes did the same.? I bring this up as the 4-400 and the 3-500 are somewhat the same in this characteristic.
Ron wa7gfe
As others mentioned the 3-500 tubes need to be ran hard
some of the time as the plate absorbs the small amount of gas in the
tube when red.? Just don't over load the tube.?
Ralph ku4pt
|
Re: Drake L75 - Plate variable capacitor damage found
Yes a mirror is a good idea.
Tim
WB8UHZ
On Monday, April 26, 2021, 9:47:00 AM EDT, Joe WB9SBD <nss@...> wrote:
Mirror?
On 4/26/2021 8:41 AM, amfone via
groups.io wrote:
If the L75 is like the L7 of
which I have two you can get a peek at the 3-500Z color by
looking through the fan on the back of the amp, yes you do
have to get to the back of the amp but you can take a look.
73 Tim
WB8UHZ
On Monday, April 26, 2021, 12:28:29 AM EDT, Roberto -
YS1RS via groups.io <ys1rs@...> wrote:
Yes, understood about the little red running of the
tube... not sherry red of course.
Only problem is that the amp is enclosed in a
chassis with interlocks... otherwise there is no way
to keep a visual on the tube... Yes, this can be done
by instruments by following the technical data of the
tube. This is my next step in my learning journey.
Still looking for a brand new tube though this one
is working but, under the condition I found this amp,
I can see has been abused by the damage on the plates
of the variable cap.?
YS1RS
I'll jump in here as well on how hard these
tubes need to be run to keep them happy;
I ran a Bauer 707 AM transmitter many years
ago while in Korea at an AFKN station.? That
transmitter used 4-400 tubes for RF out and for
the modulator.? The plates on the finals stayed
red all the time and they were happy.? I believe
if my memory is correct the modulator tubes did
the same.? I bring this up as the 4-400 and the
3-500 are somewhat the same in this
characteristic.
Ron wa7gfe
As others mentioned the 3-500
tubes need to be ran hard some of the time as
the plate absorbs the small amount of gas in
the tube when red.? Just don't over load the
tube.?
Ralph ku4pt
|
Re: Drake L75 - Plate variable capacitor damage found
Mirror?
On 4/26/2021 8:41 AM, amfone via
groups.io wrote:
toggle quoted message
Show quoted text
If the L75 is like the L7 of
which I have two you can get a peek at the 3-500Z color by
looking through the fan on the back of the amp, yes you do
have to get to the back of the amp but you can take a look.
73 Tim
WB8UHZ
On Monday, April 26, 2021, 12:28:29 AM EDT, Roberto -
YS1RS via groups.io <ys1rs@...> wrote:
Yes, understood about the little red running of the
tube... not sherry red of course.
Only problem is that the amp is enclosed in a
chassis with interlocks... otherwise there is no way
to keep a visual on the tube... Yes, this can be done
by instruments by following the technical data of the
tube. This is my next step in my learning journey.
Still looking for a brand new tube though this one
is working but, under the condition I found this amp,
I can see has been abused by the damage on the plates
of the variable cap.?
YS1RS
I'll jump in here as well on how hard these
tubes need to be run to keep them happy;
I ran a Bauer 707 AM transmitter many years
ago while in Korea at an AFKN station.? That
transmitter used 4-400 tubes for RF out and for
the modulator.? The plates on the finals stayed
red all the time and they were happy.? I believe
if my memory is correct the modulator tubes did
the same.? I bring this up as the 4-400 and the
3-500 are somewhat the same in this
characteristic.
Ron wa7gfe
As others mentioned the 3-500
tubes need to be ran hard some of the time as
the plate absorbs the small amount of gas in
the tube when red.? Just don't over load the
tube.?
Ralph ku4pt
|
Re: Drake L75 - Plate variable capacitor damage found
If the L75 is like the L7 of which I have two you can get a peek at the 3-500Z color by looking through the fan on the back of the amp, yes you do have to get to the back of the amp but you can take a look.
73 Tim
WB8UHZ
On Monday, April 26, 2021, 12:28:29 AM EDT, Roberto - YS1RS via groups.io <ys1rs@...> wrote:
Yes, understood about the little red running of the tube... not sherry red of course. Only problem is that the amp is enclosed in a chassis with interlocks... otherwise there is no way to keep a visual on the tube... Yes, this can be done by instruments by following the technical data of the tube. This is my next step in my learning journey.
Still looking for a brand new tube though this one is working but, under the condition I found this amp, I can see has been abused by the damage on the plates of the variable cap.?
YS1RS
On Apr 25, 2021, at 22:02, Ron Magnus < ron.magnus@...> wrote: I'll jump in here as well on how hard these tubes need to be run to keep them happy;
I ran a Bauer 707 AM transmitter many years ago while in Korea at an AFKN station.? That transmitter used 4-400 tubes for RF out and for the modulator.? The plates on the finals stayed red all the time and they were happy.? I believe if my memory is correct the modulator tubes did the same.? I bring this up as the 4-400 and the 3-500 are somewhat the same in this characteristic.
Ron wa7gfe
As others mentioned the 3-500 tubes need to be ran hard
some of the time as the plate absorbs the small amount of gas in the
tube when red.? Just don't over load the tube.?
Ralph ku4pt
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Re: Drake L75 - Plate variable capacitor damage found
Yes, understood about the little red running of the tube... not sherry red of course. Only problem is that the amp is enclosed in a chassis with interlocks... otherwise there is no way to keep a visual on the tube... Yes, this can be done by instruments by following the technical data of the tube. This is my next step in my learning journey.
Still looking for a brand new tube though this one is working but, under the condition I found this amp, I can see has been abused by the damage on the plates of the variable cap.?
YS1RS
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On Apr 25, 2021, at 22:02, Ron Magnus < ron.magnus@...> wrote: I'll jump in here as well on how hard these tubes need to be run to keep them happy;
I ran a Bauer 707 AM transmitter many years ago while in Korea at an AFKN station.? That transmitter used 4-400 tubes for RF out and for the modulator.? The plates on the finals stayed red all the time and they were happy.? I believe if my memory is correct the modulator tubes did the same.? I bring this up as the 4-400 and the 3-500 are somewhat the same in this characteristic.
Ron wa7gfe
As others mentioned the 3-500 tubes need to be ran hard
some of the time as the plate absorbs the small amount of gas in the
tube when red.? Just don't over load the tube.?
Ralph ku4pt
|
Patrick P
Jim Shorney
Roberto - YS1RS