Re: TR-3 Band Switch Wiring
Not dumb at all.? I did the same thing when I first dug into one of these Drake transceivers.? Your sideband filters may be OK.? These are very broad filters and thus sound great on the air if they are working, not so great for adjacent channel rejection.? If your audio is sounding very pinched or tinny you may have a problem.? The options to fix it are limited and can get expensive.? I was lucky to find a TR-4 parts radio to rob the filter from.? Even this is not easy.? The early TR-4 uses the same "soup can" filter as the TR-3 so you don't want that.? The later ones use the filter set that is used in the TR-4C radios.? These are great filters but they protrude through a cutout in the chassis floor.? A cutout that is not there in the TR-3.? Mid-generation TR-4s are the best donors since they used a filter that was better than the soup can but fit in the same space.??
If you have a spectrum analyzer you can wrap a probe wire around the 9MHz carrier oscillator tube and you will see the sideband passbands when you switch from one side to the other.? set you span to about 8KHz.? This is also a good way to center your carrier. Instead of a nice 2.4kHz passband I saw a spiky response with one filter even shifted.? If you don't have a spectrum analyzer your ear will still tell you what is going on.? Note that these filters are used in both directions so what you are hearing is what others are going to hear from you when you transmit.
On Tuesday, April 1, 2025 at 11:08:17 PM CDT, Joe W7BWA via groups.io <w7bwa@...> wrote:
Barry. You have saved my bacon and I am so grateful. I spent hours trying to track this down. Thanks so much! I¡¯m really not that dumb! Lol
?
interesting on the filters. I will search it out and if I can get some, I¡¯d have a great tube radio.?
73 my friend.?
--
Joe - W7BWA
Custer, WA
|
Identifying "Soft" Final Tubes
How do you determine that your final tubes are near EOL??
?
Currently when I tune up my T-4XC, particularly when I peak the "Load" control I have to perform this really quickly to get a peak, because iP and output power will slowly fall if I hold this for more than a couple of seconds. I have to "chase" the load peak with a falling ammeter.?
?
I don't know if what I'm seeing is related more to a secondary effect, such as the cathode resistors heating up and increasing their resistance, or whether the finals themselves are getting "soft."?
?
I can still achieve >100W output on all bands. The AC-4 has been recently rebuilt. I'm sure that I can determine the root cause with time, but I'm curious how y'all determine the health of your final tubes.?
--
Craig/W8CS
Greenville, SC
|
Re: Inductance of MN-2000/L-4B Coils?
Thanks, Jim.? It isn't critical for me.? I'm just wondering with the end goal of making a similar receiving-only tuner for non-ham bands.
Barry - N4BUQ
Next time I have the L4B apart, I will measure the uh on? 80-10m.? ?Then add it to my notes.? ?I did measure the plate choke in one of my L4B's and it's 154? uh.? ? ?Then also put it on the VNA to find both 1st and 2nd series resonance points.? ?I have that info in my binder.? ?It does not resonant on any ham band, nor warc bands.?
|
Re: TR-4 - Sideband Selections
I reckon that if the sideband selection was fully in-line with the reality of our conventions that they wouldn¡¯t have needed the lamps and we would be simply selecting manually ¡ª like with the transmitters.?
I have no idea what costs were in 1963, when the original design was done. Two more crystals in, say the late 60s and 70s probably would have been cheaper than all the switching, lamps, etc would have been. Today, of course, crystals are more expensive again.?
Drake wasn¡¯t the only manufacturer that used this scheme ¡ª I believe that Swan did, also, as well as other companies.?
Steve Wedge, W1ES
Time flies like an arrow. Fruit flies like a banana.
On Wed, Apr 2, 2025 at 09:39, n4buq < n4buq@...> wrote:
Thanks for that clarification! ?
This is what I was looking for.
Barry - N4BUQ
The indicator should not be interpreted as automatically selecting the correct sideband.?
Steve Wedge, W1ES
Time flies like an arrow. Fruit flies like a banana.
On Tue, Apr 1, 2025 at 17:24, Gary WB6OGD via groups.io <
winbladgary@...> wrote:
You can tune up on either sideband using TUNE, which is an audio tone.
X is always used for CW which offsets the carrier oscillator to put its signal inside the passband of the filter (LSB filter I think).
?
20meters is the only odd ball band that uses the filters backwards (uses LSB filter for USB).? That is the only band that tunes
backwards on the PTO dial.
?
73,
Gary
WB6OGD
?
|
Re: TR-4 - Sideband Selections
Thanks for that clarification! ? This is what I was looking for.
Barry - N4BUQ
The indicator should not be interpreted as automatically selecting the correct sideband.?
Steve Wedge, W1ES
Time flies like an arrow. Fruit flies like a banana.
On Tue, Apr 1, 2025 at 17:24, Gary WB6OGD via groups.io <winbladgary@...> wrote:
You can tune up on either sideband using TUNE, which is an audio tone.
X is always used for CW which offsets the carrier oscillator to put its signal inside the passband of the filter (LSB filter I think).
?
20meters is the only odd ball band that uses the filters backwards (uses LSB filter for USB).? That is the only band that tunes
backwards on the PTO dial.
?
73,
Gary
WB6OGD
?
|
Re: Inductance of MN-2000/L-4B Coils?
Next time I have the L4B apart, I will measure the uh on? 80-10m.? ?Then add it to my notes.? ?I did measure the plate choke in one of my L4B's and it's 154? uh.? ? ?Then also put it on the VNA to find both 1st and 2nd series resonance points.? ?I have that info in my binder.? ?It does not resonant on any ham band, nor warc bands.?
|
Re: R4C low audio on SSB/CW
The 50k oscillator is solid state, so likely not a tube issue.?
Steve Wedge, W1ES
Time flies like an arrow. Fruit flies like a banana.
On Tue, Apr 1, 2025 at 19:45, Rob Sherwood via groups.io < rob@...> wrote: Check the 50 kHz LO injection into the product detector and the second mixer. ?This is not a typical failure. ?Rob, NC0B?
On Apr 1, 2025, at 4:00?PM, Scott N1IA via groups.io <soakland5@...> wrote:
?
Hello:
My R4C has suddenly developed very low receive audio on SSB/CW. It seems fine on AM. Is there a particular tube I should suspect as bad?
Thanks
Scott N1IA
|
Re: TR-4 - Sideband Selections
Actually, there is no TUNE position on a TR3/4. One uses CW for tuning. Then, when going on SSB, use the SIDEBAND switch to select the proper sideband.?
The indicator should not be interpreted as automatically selecting the correct sideband.?
Steve Wedge, W1ES
Time flies like an arrow. Fruit flies like a banana.
On Tue, Apr 1, 2025 at 17:24, Gary WB6OGD via groups.io < winbladgary@...> wrote:
You can tune up on either sideband using TUNE, which is an audio tone.
X is always used for CW which offsets the carrier oscillator to put its signal inside the passband of the filter (LSB filter I think).
?
20meters is the only odd ball band that uses the filters backwards (uses LSB filter for USB).? That is the only band that tunes
backwards on the PTO dial.
?
73,
Gary
WB6OGD
?
|
Re: getting the AC mains out of the TR7
An even simpler soft start is to add inside the PS7 a NTC inrush limiter as found in every SMPS nowdays. /g/DRAKE-RADIO/files/TR-7/PS7-Inrush.pdfOn Wed, 02 Apr 2025 03:05:50 -0700 "atlasstuff via groups.io" <g4fph@...> wrote: Going further I thought, that small box could easily house a resistor and another switch to make a simple, manual soft-start arrangement for the power supply. -- 73 -Jim NU0C
|
Re: getting the AC mains out of the TR7
Glenn,
?
Mine is another vote for never looping the AC primary circuit into a transceiver.
?
I had a similar idea to you. As the PS7 has no mains on/off switch of it's own, I thought I would get hold of a chassis mount version of the relevant miniature-Jones connector and mount it on a small box. Also on the box, I would install a mains on/off switch that connected across the relevant pins of the connector. Going further I thought, that small box could easily house a resistor and another switch to make a simple, manual soft-start arrangement for the power supply. Add a fuse to protect the soft-start resistor, plus suitable indicator(s) to make it fancy, if you like!
?
Not done it yet, as those 10-pin connectors are hard to come by on this side of the pond, plus I've been powering my TR4310 and TR7 from Non-Drake supplies.
?
I have changed the fans on both transceivers to common-or-garden 12 Volt, PC types. With the full 12 (13.8) V across them, they suck a lot of air, but are quite noisy in the process. So, I added a series resistor of around 50 Ohm in their DC feed. That reduces the voltage on the fans to something like 50% of rated and seemed to give a good compromise between airflow and dBA. I obtained the 12 V feed for the fans from one of the mini-Jones on the TR rear panel. I left the wiring and original connector in place for the Drake fan, to make the mod. was fully reversible / just in case a future owner does not share my outlook.
?
(I have implemented a similar arrangement with a Heathkit HW-101 that I am restoring. Some of the matching Heath power supplies do not have a mains on/off switch on their front panels. And were those 11-pin sockets really rated to take the heater Amps and PA anode Volts that they have to put up with?!?)
?
Regards,
?
Mark.
?
|
Re: getting the AC mains out of the TR7
Just a thought for a simple option but not that smart.
I have a few tube KW Electronics transceivers (in addition to Drakes).? Two were bought with an on off switch on the power supply unit, being home mods.
But the TR7 fan is an issue since I assume it would be AC only.?
Nigel
On 2025-04-01 13:15, n4buq wrote:
> Perhaps a switch that responds to commands spoken in Morse code.
*** I've used code for I/O on a few projects.? Well, mostly for O.
Once upon a time, I was working on a project at work that had a CPU that
talked to
another CPU.? They communicated via a shared memory interface.? The CPU
I was working on had no I/O, except for a single reset line to the main
CPU -
so it could act as a watchdog.? I got the program working fine on the
ICE ( In Circuit
Emulator ).? But when I plugged in a real CPU, it sat like a lump and
did nothing.
I beat my head against the wall with that thing for about a week, then
had an idea...
I brought in a small speaker and a resistor.? Hooked them to that one
I/O line, and
wrote a quickie morse code driver.? "If you get here, send an "A", if
you get there, send a "B"....etc.
Had it figured out in about 15 minutes.
Another one:? ?I was doing these back exercises, each movement to be
held for 5 seconds.? Sure would
be nice to have a box with a button that would beep after 5 seconds...
Then I thought - why not have it
count my repetitions?? And so it does....in Morse code.
A third one:? Somebody posted an adventure game on Hackaday with Morse
code input & output.? It worked
with a blinking light.? I modified it so it would beep instead.? Much
more ham-friendly.? I'm going to
put it in a nice little box and take it to the local radio club meeting.
? ? ? ? ? ? ? ? ?- Jerry, KF6VB
>
> Barry - N4BUQ
>
>> On 2025-03-31 21:06, Jim Shorney via wrote:
>>
>>>
>>>
>>
>> *** Or you could get a "clapper" :).
>>
>>
>>
>>? ? ? ? ? ? ? ? - Jerry, KF6VB
>>
>>>
>>> Supposedly capable of switching 15A and it sounds like they can
>>> handle
>>> moderately inductive loads. Problem solved. Although I did have to
>>> think about what to use the other two in the three-pack for. There
>>> was
>>> nothing in the shack that I "need" to turn on and off wirelessly but
>>> I
>>> found something to use the second one for. They have been working
>>> well
>>> for several months. We'll see if they survive our thunderstorm
>>> season.
>>> Ironically, I did put the third one in the shack last week so I could
>>> remotely reboot my LAN connected SDR receiver when it drops off the
>>> network. I suppose you could use one to turn the PS7 and a FA7 on the
>>> rig on at the same time, saving having to rig up a DC fan. It would
>>> take just a short extension cord from the FA7 to the 2nd receptacle
>>> on
>>> the box.
>>>
>>> 73
>>>
>>> -Jim
>>> NU0C
>>>
>>> On Mon, 31 Mar 2025 20:21:31 -0700
>>> "Glenn Hetchler WB0DKT via " <ghetch=[email protected]>
>>> wrote:
>>>
>>>> I never liked the fact that there was the AC for the PS7 routed
>>>> through the TR7. I have used a good power strip for years and tried
>>>> to
>>>> not switch the volume control to OFF since I read about them being
>>>> unobtainable, and failing both electrically and mechanically.
>>>>
>>>> Working on a project TR7 and PS7 with a younger ham, I decided that
>>>> I
>>>> should finally figure out how to keep the AC out of his and my TR7s.
>>>> As we were checking out the PS7 I looked at the circuit board that
>>>> has
>>>> the voltage switching and all that (mounted by the switches being
>>>> pop-riveted in place, seriously???) and decided there had to be a
>>>> better way that to mess with that wiring.
>>>>
>>>> And then an idea came to me that should have 40+ yrs ago when I got
>>>> the rig. Surplus Sales has the Jones connectors (for a cable, but we
>>>> did not connect any cable) that are the same configuration as on the
>>>> back of the rig. Part Number: (CNE) P310CCT
>>>>
>>>>
>>>> With it we just jumpered pins 1-2 and 3-4 inside the connector
>>>> (check
>>>> your PS7 and TR7 manuals to see) and then plugged it on to the cable
>>>> from the PS7 and it works just like the PS7 was plugged into a
>>>> turned-on radio. If you need ALC or VOX, you'll need to get another
>>>> connector to plug-in to the back of the TR7, but we have not needed
>>>> either yet.
>>>>
>>>> Then we leave the PS7 cable that has the AC and wires for the ALC
>>>> and
>>>> VOX coiled up behind the PS7 and turn things on with the power
>>>> strip.
>>>> Now only the 12V cable is plugged into the TR7. Of course the fan
>>>> will
>>>> need to be changed to 12 VDC on the radio. That will be our next
>>>> upgrade.
>>>>
>>>> Before recommending the Jones connector from Surplus Sales to the
>>>> group, I called them to make sure there were more available. They
>>>> checked stock and said that they should have at least several
>>>> hundred.
>>>>
>>>> Thought I'd share this idea with the group. I am sure others may
>>>> have
>>>> done something similar, but it is nice to know where we can still
>>>> get
>>>> Jones connectors at a reasonable price.
>>>>
>>>> 73,
>>>> -Glenn/ WB0DKT
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>>
>>> --
>>>
>>> 73
>>>
>>> -Jim
>>> NU0C
>>>
>>>
>>>
>>
>>
>>
>
>
>
|
Re: TR-3 Band Switch Wiring
Very insightful Gary. I really appreciate this education. That is why I enjoy getting my hands dirty in these vintage rigs. 73.
--
Joe - W7BWA
Custer, WA
|
Re: TR-3 Band Switch Wiring
OK, in this case, antenna for calibrator - but the gimmick story is still true.. A d using this as an antenna still counts as a ¡°gimmick¡± in my book. It takes the place of a capacitor that could have performed the same task.
Gary
toggle quoted message
Show quoted text
On Apr 1, 2025, at 10:13?PM, Gary Follett via groups.io <xntrick1948@...> wrote:
? That is what was known as a ¡°gimmick¡±. This was a way to tweak a circuit to work. Often they had two wires wrapped around each other, each end being tied to a circuit point. The calibration technician literally cut the length of this ¡°gimmick capacitor¡± to get the circuit to work.?
This was a cheap, simple and crusty way to correct for uncontrollable variables in the radio assembly processes. A?
Your wire is likely meant as an adjustable stray inductance, whose value could be set with a wire nipper, once-and-for-all.?
Don¡¯t remove it, put it back where it was and leave it alone.
Gary
W0DVN On Apr 1, 2025, at 10:05?PM, Barry KJ5GQM via groups.io <chasbg@...> wrote:
?
It serves as the antenna for the calibrator signal. ?Not sure why Drake did it that way. It¡¯s confused many in the past including myself. Good luck with the TR-3. I have two of them. My favorite radio is my TR-3 with TR-4 sideband filters in it. ?You may find that audio is not ideal on one or both sidebands. The TR-3 filters are its greatest weakness. You can find more details here with some simple searches.
On Tuesday, April 1, 2025 at 10:39:51 PM CDT, Joe W7BWA via groups.io <w7bwa@...> wrote:
WARNING:? I am a hobbyist and I am learning vintage radios. I can usually find my way around schematics to some degree, but not well. I do better with service manuals and I've not found any for Drakes. I may also use wrong terminology for the parts I describe, so I have included photos. Please be patient with me and don't roll your eyes if my question is dumb.
?
I'm refurbishing and recapping a TR-3. I have a mystery that I'm hoping the Drake brain trust can help me with...
?
While cleaning up the very dirty band switch of this radio, I came across a white/brown wire that appears to go to nowhere.
I know I did not knock it off and without my flashlight, I would have never seen the unconnected end under the band switch. The wire begins on the top of the chassis on a lug attached to a little vertical circuit board adjacent to V11 I believe (see photo). This white/brown wire goes from this little board, through a rubber grommet, through a hole on the top end of a wafer board. Then it was bent downward next to the band switch wafer and not connected to anything.
?
The other part of the mystery is oddly this end of the wire does not appear to have been ever connected. The strands of wire are far inside the insulation (see photo). There are no strands coming out of this wire, nor the bottom of the switch wafer.
?
Many thanks. 73. Joe
?
--
Joe - W7BWA
Custer, WA
|
Re: TR-3 Band Switch Wiring
That is what was known as a ¡°gimmick¡±. This was a way to tweak a circuit to work. Often they had two wires wrapped around each other, each end being tied to a circuit point. The calibration technician literally cut the length of this ¡°gimmick capacitor¡± to get the circuit to work.?
This was a cheap, simple and crusty way to correct for uncontrollable variables in the radio assembly processes.?
Your wire is likely meant as an adjustable stray inductance, whose value could be set with a wire nipper, once-and-for-all.?
Don¡¯t remove it, put it back where it was and leave it alone.
Gary
W0DVN
toggle quoted message
Show quoted text
On Apr 1, 2025, at 10:05?PM, Barry KJ5GQM via groups.io <chasbg@...> wrote:
?
It serves as the antenna for the calibrator signal. ?Not sure why Drake did it that way. It¡¯s confused many in the past including myself. Good luck with the TR-3. I have two of them. My favorite radio is my TR-3 with TR-4 sideband filters in it. ?You may find that audio is not ideal on one or both sidebands. The TR-3 filters are its greatest weakness. You can find more details here with some simple searches.
On Tuesday, April 1, 2025 at 10:39:51 PM CDT, Joe W7BWA via groups.io <w7bwa@...> wrote:
WARNING:? I am a hobbyist and I am learning vintage radios. I can usually find my way around schematics to some degree, but not well. I do better with service manuals and I've not found any for Drakes. I may also use wrong terminology for the parts I describe, so I have included photos. Please be patient with me and don't roll your eyes if my question is dumb.
?
I'm refurbishing and recapping a TR-3. I have a mystery that I'm hoping the Drake brain trust can help me with...
?
While cleaning up the very dirty band switch of this radio, I came across a white/brown wire that appears to go to nowhere.
I know I did not knock it off and without my flashlight, I would have never seen the unconnected end under the band switch. The wire begins on the top of the chassis on a lug attached to a little vertical circuit board adjacent to V11 I believe (see photo). This white/brown wire goes from this little board, through a rubber grommet, through a hole on the top end of a wafer board. Then it was bent downward next to the band switch wafer and not connected to anything.
?
The other part of the mystery is oddly this end of the wire does not appear to have been ever connected. The strands of wire are far inside the insulation (see photo). There are no strands coming out of this wire, nor the bottom of the switch wafer.
?
Many thanks. 73. Joe
?
--
Joe - W7BWA
Custer, WA
|
Re: TR-3 Band Switch Wiring
Barry. You have saved my bacon and I am so grateful. I spent hours trying to track this down. Thanks so much! I¡¯m really not that dumb! Lol
?
interesting on the filters. I will search it out and if I can get some, I¡¯d have a great tube radio.?
73 my friend.?
--
Joe - W7BWA
Custer, WA
|
Re: TR-3 Band Switch Wiring
It serves as the antenna for the calibrator signal. ?Not sure why Drake did it that way. It¡¯s confused many in the past including myself. Good luck with the TR-3. I have two of them. My favorite radio is my TR-3 with TR-4 sideband filters in it. ?You may find that audio is not ideal on one or both sidebands. The TR-3 filters are its greatest weakness. You can find more details here with some simple searches.
On Tuesday, April 1, 2025 at 10:39:51 PM CDT, Joe W7BWA via groups.io <w7bwa@...> wrote:
WARNING:? I am a hobbyist and I am learning vintage radios. I can usually find my way around schematics to some degree, but not well. I do better with service manuals and I've not found any for Drakes. I may also use wrong terminology for the parts I describe, so I have included photos. Please be patient with me and don't roll your eyes if my question is dumb.
?
I'm refurbishing and recapping a TR-3. I have a mystery that I'm hoping the Drake brain trust can help me with...
?
While cleaning up the very dirty band switch of this radio, I came across a white/brown wire that appears to go to nowhere.
I know I did not knock it off and without my flashlight, I would have never seen the unconnected end under the band switch. The wire begins on the top of the chassis on a lug attached to a little vertical circuit board adjacent to V11 I believe (see photo). This white/brown wire goes from this little board, through a rubber grommet, through a hole on the top end of a wafer board. Then it was bent downward next to the band switch wafer and not connected to anything.
?
The other part of the mystery is oddly this end of the wire does not appear to have been ever connected. The strands of wire are far inside the insulation (see photo). There are no strands coming out of this wire, nor the bottom of the switch wafer.
?
Many thanks. 73. Joe
?
--
Joe - W7BWA
Custer, WA
|
WARNING:? I am a hobbyist and I am learning vintage radios. I can usually find my way around schematics to some degree, but not well. I do better with service manuals and I've not found any for Drakes. I may also use wrong terminology for the parts I describe, so I have included photos. Please be patient with me and don't roll your eyes if my question is dumb.
?
I'm refurbishing and recapping a TR-3. I have a mystery that I'm hoping the Drake brain trust can help me with...
?
While cleaning up the very dirty band switch of this radio, I came across a white/brown wire that appears to go to nowhere.
I know I did not knock it off and without my flashlight, I would have never seen the unconnected end under the band switch. The wire begins on the top of the chassis on a lug attached to a little vertical circuit board adjacent to V11 I believe (see photo). This white/brown wire goes from this little board, through a rubber grommet, through a hole on the top end of a wafer board. Then it was bent downward next to the band switch wafer and not connected to anything.
?
The other part of the mystery is oddly this end of the wire does not appear to have been ever connected. The strands of wire are far inside the insulation (see photo). There are no strands coming out of this wire, nor the bottom of the switch wafer.
?
Many thanks. 73. Joe
?
--
Joe - W7BWA
Custer, WA
|
Re: TR-4CW and TR7 Outcomes?
Let's make this easy. Pull the board and out it on your bench. Connect 10 volts to pin 11/38 and ground to 11/11. Make your measurements with and without the transistor on the board. Verify the pinout of your transistor against a data sheet and verify it is good with am Ohmmeter check. Where did you get your transistors? Are you confident that they are genuine? Trace the board connections to make sure the transistor is inserted correctly. On Sat, 29 Mar 2025 20:15:04 -0300 "Jim Harris via groups.io" <radiove1rb@...> wrote: Gary I have not had time to work on the TR7 CW issue, But I think I have it
isolated the problem to the switch transistor Q1103 as with the base
having 9.4 VDC on receive it still conducts some so instead of 10 volts
there is a bit over 5 volts but that is enough to power up the oscillator
etc. Guess I am going to have to try and put in some different transistors.
It is such a simple circuit it is hard to find the problem.
Jim VE1RB -- 73 -Jim NU0C
|
Re: PTO makes scraping sound
There is no Zener in the PTO schematic you posted. :D On Mon, 31 Mar 2025 21:24:15 -0700 "VE7PS via groups.io" <ve7ps@...> wrote: Mark:
No harm in trying the battery. Good chance it will be close enough to fire
it up for a test, though maybe not as stable as the + 10V supply, as it may
not fire the zener in the PTO.
73
PS -- 73 -Jim NU0C
|
Re: getting the AC mains out of the TR7+ FAN
US Patent 4237521, conveniently stored in the group Files section for your viewing pleasure. /g/DRAKE-RADIO/files/TR-7/US4237521.pdfI proved experimentally some years ago that the final transistors are cooled much better with the fan pulling air out as Drake intended. Online advice to reverse the fan is misguided. On Tue, 1 Apr 2025 17:17:42 +0000 (UTC) "Evan via groups.io" <k9sqg@...> wrote: I've heard that the heatsink design has a patent on it (long expired) but I can't confirm that. -- 73 -Jim NU0C
|
Craig W8CS
Jim Shorney
