Re: PTO makes scraping sound
Sorry Peter you did tell me where the RIT wire goes. I forgot. Sorry!
On the PTO output signal, where does that go on the rig!
Mark
|
Re: PTO makes scraping sound
I didn¡¯t get a chance to check yet. I am just so tired from working all day. But soon I will check!
Question: I am having trouble looking at the PTO schematic for the TR-4CW/RIT and trying to figure out where the OUTPUT signal from PTO and the RIT wire goes to on the rig. The only schematic for the rig that I have is for the TR-4C not the TR-4CW/RIT.
So I just need to know where the PTO output signal goes when it comes out of the PTO and also where the RIT wire from the PTO goes.
Mark
|
Re: getting the AC mains out of the TR7
Jim Thank you for bringing that info on the huge in-rush and the solution to my attention. Brilliant fand from Stefan, so it must be good. I did not know that this type of thermistor existed. ? With that mega transformer in the PS7, it will deliver a big punch, and a simple solution.? I have put in thermistors after the mains fuse on tube receivers (all Class A) which have the silicon rectifiers.? More important to me since I am contemplating adding a 1 farad capacitor (from a car boom audio shop but never used) to stiffen the TR7 on Transmit.? Pity it does not fit in the case.
Nigel
A better soft start solution:
/g/DRAKE-RADIO/files/TR-7/PS7-Inrush.pdf
On Wed, 2 Apr 2025 19:01:52 +0100
"nigel patterson G3YDT via " <wnigelpatterson=[email protected]> wrote:
> Yes, good solutions for the fans and keeping the mains out and a simple
> switch to override the soft start resistor.
--
73
-Jim
NU0C
|
Re: Identifying "Soft" Final Tubes
Hello all,
¡®Somewhere¡¯, years ago, I read ¡®something¡¯ about the typical sweep tubes, stating they were being used WAY beyond their ratings.
It was because of SSB duty cycle of ~18% that they were even used at all.
This is only what my ¡®old mind¡¯ remembers.
The 6146 has got to have better numbers.
Maybe they should have used 4D32¡¯s like the Collins 32V2 used (hard to kill those WWII radar tubes).
73 de Steve NR4M
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On Apr 2, 2025, at 8:06?PM, Steve Wedge, W1ES/4 via groups.io <w1es@...> wrote:
I don't know where the perception that sweep tubes are delicate came from. They're really not any more delicate than the famous 6146.
|
How early T-4X?? Mine is S/N 10499.? My T-4X is on the needs to be
fixed list, but I can take a look tomorrow with an open key in the
key jack.
73
Stan
KM4HQE
On 4/2/25 18:51, Steve Wedge, W1ES/4
via groups.io wrote:
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Show quoted text
Working
on a T-4 that I sold and has come back for repairs after UPS
played Mad Max with it.? I can't remember if the functionality
of TUNE and SSB are dependent on there NOT being an open key in
the KEY jack.
This
makes sense merely because the TR-3 and TR-4 function that way
but I can't check against my T-4X because the T-4X is a very
late one that is more similar to a T-4XB (4-wafer FUNCTION
switch),
Anyone
out there with an early T-4X or a T-4 that can verify this for
me?? If I close the key (when it's inserted into the KEY
connector), I can use TUNE, SSB and AM.? If the key is open,
TUNE, SSB and AM don't work.
If
I'm correct, I can send this back to its new owner. Hopefully,
UPS won't abuse it again!
73,
Steve Wedge, W1ES
Time flies like an arrow.? Fruit flies like a banana.
Sent with secure email.
|
Re: Identifying "Soft" Final Tubes
Back in the day, I built a linear with 4 6LQ6 tubes ( in an ARC-5 cabinet ).
I used Radio Shack "lifetime warranty" tubes, and carefully put the receipt in
an envelope taped to the bottom of the linear.
- Jerry, KF6VB
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On 2025-04-02 17:47, Jim Shorney via groups.io wrote: Probably because sweeps are pulse tubes and are not built to take high
levels of average power. The 6146 and such were more robustly built
and would typically be used in FM or AM service.
On Thu, 03 Apr 2025 00:06:42 +0000
"Steve Wedge, W1ES/4 via groups.io" <w1es@...> wrote:
I don't know where the perception that sweep tubes are delicate came from. They're really not any more delicate than the famous 6146. --
73
-Jim
NU0C
|
If it's a soup can filter failure is not at all rare.? Just because you have a TR-4 doesn't mean you don't have a soup can either.? You have to check.? Early TR-4s used the soup can.? I have two TR-3s and the soup can was bad in both.? Centering the carrier oscillator by the "switch back and forth and listen" method can place your carrier way off of center because you are basically trying to find a common tone between two filters and one or both of them may have drifted or lost a crystal or two.? It's best to look at the filter response with a spectrum analyzer to see if the filters are wonky.? You can also use it to perfectly center the carrier at 9MHz rather than using the tone sound method.
Now if you don't have a soup can filter I would agree that filter failure is probably not your problem.? Center the carrier and suppress it properly and try another mic.
On Wednesday, April 2, 2025 at 06:25:55 PM CDT, Richard Knoppow via groups.io <1oldlens1@...> wrote:
? ? ? Its important not to confuse carrier _balance_ with carrier
centering. Both could be affected if the carrier frequency is off.
Balance has to do with the amount of residual carrier. Too much carrier
is not good but will not affect the sound of the signal. If the carrier
is not centered the whole signal will be moved toward one of the
sideband filters. So, one sideband will have too much low end and the
other too much high end. Excessive low end and not enough high end can
result in its sounding muffled and perhaps garbled. Garbled audio can
come from the carrier being moved from where its expected to be. The
effect of tuning too high or too low. If far enough displaced it can
destroy intelligibility. In general carrier balance will not do this
although if there is enough carrier it can result in the same sort of
sound? that mis-tuned SSB does. So, probably both should be looked for.
My guess (and its only a guess) is that the carrier is not centered
between the two filters. The carrier MUST be centered before adjusting
the balance. The carrier will be between the filters in a? location
where it is attenuated a lot so a sensitive method must be used to get
it exactly balanced. The carrier may be _unballanced_ to deliberately
increase it in order to find the center of the two filters. The carrier
should be attenuated the same amount on both sides. While its suggested
that the RF meter be used for this I find its really not sensitive
enough. A pick up loop on a receiver works well and does not couple
enough to damage the receiver. Once you have the carrier centered you
can adjust it for balance. The modulator used by Drake has virtually
infinite carrier attenuation so something like a receiver or
oscilloscope is best for adjusting it. There are two adjustments, level
and capacitance. The should be juggled to get the absolute minimum. It
will be very far under the nominal output, perhaps 60db. Once set it
will not have to be adjusted again for a long time.
? ? If the carrier is _centered_ correctly the audio quality of the two
sidebands should be nearly the same. The receiver may make some
difference but it should be much. Again, once properly adjusted this
won't have to be touched again for a long time. Drake has very good
residual side band reduction as well as very good carrier reduction. The
TR-4 has good sideband filters, better than the TR-3 and there should be
little or no quality difference unless one of the filters is defective.
That does happen but is rare.
? ? My guess is that routine alignment will fix this problem however,
do keep in mind that one or even both of the sideband filters may be
faulty although its pretty rare.
On 4/2/2025 3:17 PM, Craig W8CS via groups.io wrote:
> I would echo what Richard said; you can tell if your carrier balance is
> off if (for example) LSB sounds muffled and USB sounds tinny. Repeat
> your monitor test on different bands/different sidebands.
> If that is the case, it's pretty easy to fix, I picked up a tip from
> Steve on this site that was posted a couple of years ago on how to
> center this. Yell if you need us to regurgitate.
> --
> Craig/W8CS
> Greenville, SC
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
|
Re: TR-3 Band Switch Wiring
Barry, this is awesome. Thanks so much!?
I have the equipment to do the sweep. I¡¯ll do as you suggested.?
This TR-3 was not treated well. I¡¯ve cleaned it up and recapped it. I think I will sell it to someone that likes it as is - baked on old dust on the chassis. I¡¯ve cleaned it as much as possible without stripping the chassis.?
I think once sold, I¡¯ll look for a clean 3 and maybe invest in filters if I can hunt some down. Then I¡¯ll have one awesome TR-3!
?
Many thanks again. 73.
--
Joe - W7BWA
Custer, WA
|
Re: Identifying "Soft" Final Tubes
Probably because sweeps are pulse tubes and are not built to take high levels of average power. The 6146 and such were more robustly built and would typically be used in FM or AM service. On Thu, 03 Apr 2025 00:06:42 +0000 "Steve Wedge, W1ES/4 via groups.io" <w1es@...> wrote: I don't know where the perception that sweep tubes are delicate came from. They're really not any more delicate than the famous 6146. -- 73 -Jim NU0C
|
Have you guys/gals seen this ?
?
Thought someone here might have an interest.
?
de Jim W4QE
?
|
Re: getting the AC mains out of the TR7
A better soft start solution: /g/DRAKE-RADIO/files/TR-7/PS7-Inrush.pdfOn Wed, 2 Apr 2025 19:01:52 +0100 "nigel patterson G3YDT via groups.io" <wnigelpatterson@...> wrote: Yes, good solutions for the fans and keeping the mains out and a simple
switch to override the soft start resistor. -- 73 -Jim NU0C
|
Re: Identifying "Soft" Final Tubes
Actually, sweep tubes used in TV service, back in the day, were beat upon fairly hard.
What you don't want to do, with ANY tube transmitter, is run heavy plate current OFF-RESONANCE.? When that is done, the dissipation ratings are probably being exceeded.? This can happen with 6JB6's but also with 6146's, 811's and 3-500Z's.? It is important to get the PLATE tuning at least into the "ballpark" when tuning.? You can do this with low plate current, then increase drive and fine-tune the loading and the RF TUNE adjustments.
I don't know where the perception that sweep tubes are delicate came from.? They're really not any more delicate than the famous 6146.
73,
Steve Wedge, W1ES
Time flies like an arrow.? Fruit flies like a banana.
Sent with secure email.
On Wednesday, April 2nd, 2025 at 5:27 PM, amfone via groups.io <amfone20000@...> wrote:
You should always tune up FAST for the Drake gear, these are sweep tubes. One way to check the quality of the tube is to set the bias to the proper point and transmit for about 3 minutes or more using SSB and if you see the Bias rise you have a weak tube or tubes.
73 Tim
WB8UHZ
On Wednesday, April 2, 2025 at 11:33:51 AM EDT, John Magliacane via groups.io <kd2bd@...> wrote:
On Wednesday, April 2, 2025 at 10:28:21 AM EDT, Craig W8CS via groups.io <craig_severson@...> wrote:
> How do you determine that your final tubes are near EOL?
Craig,
The "sagging" plate current or RF output effects you saw are evidence of a soft tube somewhere in the transmitter chain.
If you have a tube tester, you can try lowering the filament voltage a volt or two and observing what the tester reports in terms of Merit or Transconductance. A tube that is reaching EOL will produce an obvious drop in in tube tester response when the filament voltage is lowered. A good tube with a lot of "life" remaining will remain fairly steady, even with slightly lower filament voltage.
73 de John, KD2BD
|
Working on a T-4 that I sold and has come back for repairs after UPS played Mad Max with it.? I can't remember if the functionality of TUNE and SSB are dependent on there NOT being an open key in the KEY jack.
This makes sense merely because the TR-3 and TR-4 function that way but I can't check against my T-4X because the T-4X is a very late one that is more similar to a T-4XB (4-wafer FUNCTION switch),
Anyone out there with an early T-4X or a T-4 that can verify this for me?? If I close the key (when it's inserted into the KEY connector), I can use TUNE, SSB and AM.? If the key is open, TUNE, SSB and AM don't work.
If I'm correct, I can send this back to its new owner. Hopefully, UPS won't abuse it again!
73,
Steve Wedge, W1ES
Time flies like an arrow.? Fruit flies like a banana.
Sent with secure email.
|
Re: TR-4 - Sideband Selections
12BA6 RF amp and 6EA8's can affect signal strengths.
Steve Wedge, W1ES
Time flies like an arrow.? Fruit flies like a banana.
Sent with secure email.
On Wednesday, April 2nd, 2025 at 2:17 PM, n4buq <n4buq@...> wrote:
Yes, I checked those.? They all were probably quite close and I tweaked them to make sure.? All three 10M bands are quite close in negative voltages and the frequencies are extremely close to what they should be.? On the scope, I can see the band switch is fiddly-noisy when I switch between the three 10M bands.? I think I need to see if there are any obvious problems with those wafers and maybe clean them just a bit.? I need to recheck if I can get output on the two upper bands now.
Thanks,
Barry - N4BUQ
From: "Steve Wedge, W1ES/4 via groups.io" <w1es@...>
To: "DRAKE-RADIO" <[email protected]>
Sent: Wednesday, April 2, 2025 11:49:17 AM
Subject: Re: [DRAKE-RADIO] TR-4 - Sideband Selections
Gary, frequently the problem with the upper 10m bands could be that the xtals aren¡¯t there. If you have all three 10m xtals, look in the alignment section on aligning the three band oscillators (L1, L2 and L5). Set your scope or VTVM on the test point near V1 and adjust each per the manual for peak voltage.?
I just worked on an older TR-4 where the calibrator sounded very rough on all three segments and performance was poor. An adjustment of the 10m coil fixed it all.?
Steve Wedge, W1ES
Time flies like an arrow. Fruit flies like a banana.
On Wed, Apr 2, 2025 at 11:42, n4buq <n4buq@...> wrote:
Thank you for that attachment.? I'll give it a closer read later but the last five pictures are quite helpful.? I think what I mostly confused myself was that I didn't have a key inserted so switching to some of those positions would automatically cause the rig to transmit.? Plugging in a key resolved that for me but I was still questioning the need to go to "X" for the sideband switch because I [mis]understood that X always implied CW.? Steve's answer and Jeff's document straightened that out for me.? The manual certainly discusses Jeff's explanations but I think Jeff's may be a bit clearer - at least to me.? Thanks again guys!
Now to determine why I don't get any output on the two upper 10M bands.? The oscillator is working for all three (verified by the scope and frequency counter) so something else is amiss.? So much fun with this "new" rig!
Barry - N4BUQ
Sorry, I was thinking T-4X and the TUNE mode..
Attached? is a WA8SAJ article that really explains the TR-4..
73,
Gary
WB6OGD
|
I have the original manual for mine and it's just a TR-4C with a few added pages and a sticker added to the front cover.
Steve Wedge, W1ES
Time flies like an arrow.? Fruit flies like a banana.
Sent with secure email.
On Wednesday, April 2nd, 2025 at 2:28 PM, Paul Christensen via groups.io <pbc.law@...> wrote:
Thanks, Peter.? I¡¯ll have a look.
?
Paul, W9AC
?
?
Paul:
Check under the sub-directory?of "VERSIONS".? That's where there are three files that refer to the TR-4CW/rit in my very early K4OAH "CD".
?
On Wed, Apr 2, 2025 at 10:25?AM Paul Christensen via
<pbc.law=[email protected]> wrote:
As I recall, there¡¯s no TR-4Cw/RIT manual as such.? I¡¯ve been relying on the non-RIT manual with a two-page RIT addendum.?
But if I¡¯m wrong¡I would sure like a copy.
?
I do have K4OAH¡¯s TR-4C service manual but the included schematic does show D6.? Did he produce a service manual specific
to the Cw/RIT model?
?
Any informed guesses as to why there¡¯s no PTO Zener regulation in the RIT model?
?
Paul, W9AC
?
?
Good point Jim.....the zener is there (D6) in the late TR-4C's, and probably the TR-4CW's, but it's not in the TR-4CWrit.
My bad.? I recall Garey telling me he'd documented over 40 different
electrical versions of the 4-line PTO's.? I need to do a better?job of keeping up!
Not likely to happen though.? I'm too old.
Mark - good to hear you got the PTO rebuilt OK and at least it's working fine.
?
There is no Zener in the PTO schematic you posted. :D
|
Its important not to confuse carrier _balance_ with carrier centering. Both could be affected if the carrier frequency is off. Balance has to do with the amount of residual carrier. Too much carrier is not good but will not affect the sound of the signal. If the carrier is not centered the whole signal will be moved toward one of the sideband filters. So, one sideband will have too much low end and the other too much high end. Excessive low end and not enough high end can result in its sounding muffled and perhaps garbled. Garbled audio can come from the carrier being moved from where its expected to be. The effect of tuning too high or too low. If far enough displaced it can destroy intelligibility. In general carrier balance will not do this although if there is enough carrier it can result in the same sort of sound that mis-tuned SSB does. So, probably both should be looked for. My guess (and its only a guess) is that the carrier is not centered between the two filters. The carrier MUST be centered before adjusting the balance. The carrier will be between the filters in a location where it is attenuated a lot so a sensitive method must be used to get it exactly balanced. The carrier may be _unballanced_ to deliberately increase it in order to find the center of the two filters. The carrier should be attenuated the same amount on both sides. While its suggested that the RF meter be used for this I find its really not sensitive enough. A pick up loop on a receiver works well and does not couple enough to damage the receiver. Once you have the carrier centered you can adjust it for balance. The modulator used by Drake has virtually infinite carrier attenuation so something like a receiver or oscilloscope is best for adjusting it. There are two adjustments, level and capacitance. The should be juggled to get the absolute minimum. It will be very far under the nominal output, perhaps 60db. Once set it will not have to be adjusted again for a long time.
If the carrier is _centered_ correctly the audio quality of the two sidebands should be nearly the same. The receiver may make some difference but it should be much. Again, once properly adjusted this won't have to be touched again for a long time. Drake has very good residual side band reduction as well as very good carrier reduction. The TR-4 has good sideband filters, better than the TR-3 and there should be little or no quality difference unless one of the filters is defective. That does happen but is rare.
My guess is that routine alignment will fix this problem however, do keep in mind that one or even both of the sideband filters may be faulty although its pretty rare.
toggle quoted message
Show quoted text
On 4/2/2025 3:17 PM, Craig W8CS via groups.io wrote: I would echo what Richard said; you can tell if your carrier balance is off if (for example) LSB sounds muffled and USB sounds tinny. Repeat your monitor test on different bands/different sidebands.
If that is the case, it's pretty easy to fix, I picked up a tip from Steve on this site that was posted a couple of years ago on how to center this. Yell if you need us to regurgitate.
--
Craig/W8CS
Greenville, SC
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
|
I would echo what Richard said; you can tell if your carrier balance is off if (for example) LSB sounds muffled and USB sounds tinny. Repeat your monitor test on different bands/different sidebands.?
?
If that is the case, it's pretty easy to fix, I picked up a tip from Steve on this site that was posted a couple of years ago on how to center this. Yell if you need us to regurgitate.?
--
Craig/W8CS
Greenville, SC
|
Re: Identifying "Soft" Final Tubes
You should always tune up FAST for the Drake gear, these are sweep tubes. One way to check the quality of the tube is to set the bias to the proper point and transmit for about 3 minutes or more using SSB and if you see the Bias rise you have a weak tube or tubes.
73 Tim
WB8UHZ
On Wednesday, April 2, 2025 at 11:33:51 AM EDT, John Magliacane via groups.io <kd2bd@...> wrote:
On Wednesday, April 2, 2025 at 10:28:21 AM EDT, Craig W8CS via groups.io <craig_severson@...> wrote:
> How do you determine that your final tubes are near EOL?
Craig,
The "sagging" plate current or RF output effects you saw are evidence of a soft tube somewhere in the transmitter chain.
If you have a tube tester, you can try lowering the filament voltage a volt or two and observing what the tester reports in terms of Merit or Transconductance. A tube that is reaching EOL will produce an obvious drop in in tube tester response when the filament voltage is lowered. A good tube with a lot of "life" remaining will remain fairly steady, even with slightly lower filament voltage.
73 de John, KD2BD
|
More info needed: is this one sideband or both? Have you another microphone to test? One way of telling if the set is mis-aligned is just to try it on both sidebands. Muffled sounds like the highs are missing and garbled like there is a partial reverse of sidebands. Either could be mis-tuning. Mics can do all sorts of things but the easy test is just to try a different one.
If the carrier oscillator is mis-tuned you may get excessive lows on one sideband and excessive highs on the other. Its been too long since I tuned up my TR-4 to remember details but they are in the handbook.
BTW, I strongly recommend the CD sold by Garry Barrell's wife, it has a treasure of information in it which is not in the published handbooks.
toggle quoted message
Show quoted text
On 4/2/2025 1:21 PM, Adam N0ZIB via groups.io wrote: I have a TR-4 (early model with no noise blanker) that I¡¯ve recapped and aligned to the best of my abilities. ?It receives great and I get good TX output but every report I get back says they can understand me but my TX audio is crap. ?I¡¯ve listened to my signal on another radio and it sounds muffled/garbled. No hum in the signal just a very not natural sounding voice.
Mic is an Astatic 200 (going off memory). I plan to trace the audio from my mic down the Tx path to try and find the issue. ?Has anyone experienced this?
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
|
I have a TR-4 (early model with no noise blanker) that I¡¯ve recapped and aligned to the best of my abilities. ?It receives great and I get good TX output but every report I get back says they can understand me but my TX audio is crap. ?I¡¯ve listened to my signal on another radio and it sounds muffled/garbled. No hum in the signal just a very not natural sounding voice. ?
Mic is an Astatic 200 (going off memory). I plan to trace the audio from my mic down the Tx path to try and find the issue. ?Has anyone experienced this??
|
Mark N2DMI
Jim Shorney
Craig W8CS
Adam N0ZIB