Re: SR2000 Cant Null carrier
Hi Jim
What is copper butter and can you recommend any dealer who sells it?
Thanks
sam - WS4AM
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I have the opportunity to acquire a cosmetically nice and apparently unmodified HT-9. I have two issues with this purchase. First issue, because of its weight it will require a 9 hour drive one way (18 hours total and an overnight motel stay). The second major issue is it has no coils or tuning units. This is a bigger issue since I¡¯ve been unable to find anything available or even fabrication info to make my own. I would need at least 80m stuff.
I think it would be great to put this transmitter back on the air but will require some really difficult to find stuff, otherwise it will be a heavy boat anchor unable to do anything but sit there and look pretty. ? ?:<}
Tom N5AMA
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Interesting, if a band opening, I'd like to try to work you with my very excellent Lafayette HA-460, 6 meter AM rig.
K2WH
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Reading the manual on the SR-46 I'm left with the impression that it needs a VFO signal of 25 - 27 MHz. All of the VFOs I've looked at (Utica, Lafayette) output an 8.XX MHz signal. The manual goes on to indicate that the VFO signal needs to be 3-4V PP which I think my DDS VFO can handles so I'll try it when the radio gets here.? UPS claims they will deliver it tomorrow!? If the DDS VFO can serve up an adequate signal I can modify the Arduino code to display the proper doubled frequency.
I think it would be interesting to try and get a QSO with you with HT-40 someday.? Right now I have it up on the shelf to make bench space for the SR-46 but maybe after I'm done with that...
73,
--
Justin B.
KI5GKD
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Re: Sx100 question on 50.5 kc alignment
Got the signal generator down to 1 volt on the 50.5 kc signal.?
Still no luck on the correct voltage at test point B.
This really had me scratching my head at this point.
Then decided to check the values of R48 (1 meg) & R49 (820k).
They test way out of tolerance. Both around 500k.
Looking at the drawing showing the test points, it is showing both resistors at a 1 meg value.
Will replace those two later this week. I have some 1/2 watt 1 meg resistors.?
Think I will just go 1 meg on both.?
Could this also be part of my issue?
Definitely cant be helping.??
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Re: SR2000 Cant Null carrier
C, ?here I am intruding again. Re ??¡°It reads nothing on my LCR.?¡°?? ??so is it shorted?? Or really really wide open? or ¡°other¡±??? Seems strange from here. What could have happened to it? ? ?
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From: [email protected] [mailto:[email protected]] On Behalf Of W7WRX
Sent: Tuesday, April 2, 2024 7:07 PM
To: [email protected]
Subject: Re: [HallicraftersRadios] SR2000 Cant Null carrier? I cleaned and tightened everything including the bracket. No change.?
I drilled the rivets and removed the old Trimmer. It was bad. It reads nothing on my LCR.?
New trimmer reads 4 to 26 pf.? Rated at 25pf.
I had to space it from the chassis. It is different.??
plugged back in. NO change.? I can adjust the trimmer and null .5w either way.? The pot and trimmer manipulation ends at 2w output.? That is for BOTH side bands LSB and USB
GRRRRR...? I am going to look for the exact trimmer now. If anyone has one please let me know!!!
I guess I am going to have to replace the diodes, resistors and the .005. Just gut it all and start over.? This is crazy. The rig was DONE and one the air working.
C -- don??? va3drl
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Thanks for the info.? I read the AXN info, looked at the cap but didn't see anything.? I guess I will take a harder look.??
73 dave
On Tue, Apr 2, 2024 at 7:48?PM W7WRX < clark@...> wrote:
This is going to be a shorting load cap.? I just had this happen on one of my rigs. It would oscillate just exactly like you describe.
The Cap is a real sore spot of this rig.? They arc like crazy when people tune the rig at full power or with an antenna load that has some SWR.
This was documented in the papers on k9AXN website.
The document describes this problem and suggests manipulation of the three mounting screws.? Adjusting these has a huge impact on plate contact.?
What I suggest is to remove the cap and then clean and examine the plates.
Remove the three screws on side of chassis.? Use a flat screwdriver to slide the plastic coupler towards panel and off the cap shaft.??
Lean cap forward and you can get to the three solder tabs to unsolder the solid wire leads.
Once cap is out, you can get mag glass on and inspect the last section towards the rear.? I slid paper soaked in deoxit between plates and gently spun shaft to find where the plates where making contact.
If your LUCKY you can fix it.? If you can hipot test it, run it up to 600volts to make sure its fixed.
The one radio, I was able to repair it and gently bed the last few plates and eliminate?the contact and NOT even remove it.?
On the second radio the cap was just to far gone. The ball bearings had fallen out and heavy contact was made damaging the plates.
I have two spare load caps but they are NOT identical.? I have a third on the way now and think this time I got the right part.
Your welcome to the old one if you decide you can repair it. Maybe parts from it will help you.
Report back!
C
Chirp Chirp Chirp, geez.?
Hi Folks,
In the process of restoring a SR2K. In receive when I rotate the load control an oscillation / Chrip is heard on the speaker. This condition occur with or without HV.?
Thoughts Welcome,
dave
wa3gin
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Re: SR2000 Cant Null carrier
No sir. I pulled the mic amp tube.? Its the carrier leaking through.? I can adjust it from 2w to 200w.
C
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Clark,
Any chance this unwanted carrier is an audio chain issue??
73
wa3gin
On Tue, Apr 2, 2024 at 7:33?PM W7WRX < clark@...> wrote:
Thank you for the suggestion.? The radio was working and done.? It then just the next day all the sudden had the carrier.? The trimmer was in fact bad and according to Walt's guide, this is common.
I have had this problem several times now on various rigs.? The Invader 2000 had this issue and only after I shot gunned the ENTIRE circuit, Resistors, trimmers, Diodes and caps, Did it start working again. The resistors did go way up in value.
Also had this problem with my Collins S line. The 32S3C had 1 watt of carrier.? I replaced the odd diode bridge with 4 1n5711s and I added a small ceramic cap and bingo it nulled.?
I found the exact model NPO trimmers on Ebay. I ordered 5.? Its going to be a week down time. They are in New Hampshire. Just about as far as you could possibly get from my QTH.
When they get here, I will get some new small hardware and install the trimmer. It will look like factory.? I will replace ALL of it.? Every part so it is all NEW.? ?Then, Cross my fingers and key it up.??
These things have not been on and used in maybe 40 years. They have put up a hell of a fight.? But they will both be expertly repaired and work better than new when I am complete. It's just going to take more time.
C
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This is going to be a shorting load cap.? I just had this happen on one of my rigs. It would oscillate just exactly like you describe.
The Cap is a real sore spot of this rig.? They arc like crazy when people tune the rig at full power or with an antenna load that has some SWR.
This was documented in the papers on k9AXN website.
The document describes this problem and suggests manipulation of the three mounting screws.? Adjusting these has a huge impact on plate contact.?
What I suggest is to remove the cap and then clean and examine the plates.
Remove the three screws on side of chassis.? Use a flat screwdriver to slide the plastic coupler towards panel and off the cap shaft.??
Lean cap forward and you can get to the three solder tabs to unsolder the solid wire leads.
Once cap is out, you can get mag glass on and inspect the last section towards the rear.? I slid paper soaked in deoxit between plates and gently spun shaft to find where the plates where making contact.
If your LUCKY you can fix it.? If you can hipot test it, run it up to 600volts to make sure its fixed.
The one radio, I was able to repair it and gently bed the last few plates and eliminate?the contact and NOT even remove it.?
On the second radio the cap was just to far gone. The ball bearings had fallen out and heavy contact was made damaging the plates.
I have two spare load caps but they are NOT identical.? I have a third on the way now and think this time I got the right part.
Your welcome to the old one if you decide you can repair it. Maybe parts from it will help you.
Report back!
C
toggle quoted message
Show quoted text
Chirp Chirp Chirp, geez.?
Hi Folks,
In the process of restoring a SR2K. In receive when I rotate the load control an oscillation / Chrip is heard on the speaker. This condition occur with or without HV.?
Thoughts Welcome,
dave
wa3gin
|
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Show quoted text
On Tue, Apr 2, 2024 at 7:36?PM W7WRX < clark@...> wrote: I will answer my own question.? NO the cap is not an FP Style. I ordered a replacement, and it is MUCH larger. I cant find that can cap anywhere. I will have no choice but to mount new caps under the chassis.?
C
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Re: SR2000 Cant Null carrier
Clark,
Any chance this unwanted carrier is an audio chain issue??
73 wa3gin
On Tue, Apr 2, 2024 at 7:33?PM W7WRX < clark@...> wrote: Thank you for the suggestion.? The radio was working and done.? It then just the next day all the sudden had the carrier.? The trimmer was in fact bad and according to Walt's guide, this is common.
I have had this problem several times now on various rigs.? The Invader 2000 had this issue and only after I shot gunned the ENTIRE circuit, Resistors, trimmers, Diodes and caps, Did it start working again. The resistors did go way up in value.
Also had this problem with my Collins S line. The 32S3C had 1 watt of carrier.? I replaced the odd diode bridge with 4 1n5711s and I added a small ceramic cap and bingo it nulled.?
I found the exact model NPO trimmers on Ebay. I ordered 5.? Its going to be a week down time. They are in New Hampshire. Just about as far as you could possibly get from my QTH.
When they get here, I will get some new small hardware and install the trimmer. It will look like factory.? I will replace ALL of it.? Every part so it is all NEW.? ?Then, Cross my fingers and key it up.??
These things have not been on and used in maybe 40 years. They have put up a hell of a fight.? But they will both be expertly repaired and work better than new when I am complete. It's just going to take more time.
C
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I am sure that will help.? ?I am surprised?they did not already have a heavy roll off in the mic amp.? The SR2000 for example has a Super tight mic amp stage.?
Would be fun to inject a sweep or broad band noise into the rig, TX it and plot it on an SDR audio scope. I have done this many times.? Then make one change at a time to see the effect.??
I used this method to learn that 90% of the "MODS" on the net don't really do anything. Its the one coupling cap or cathode bypass that makes almost ALL of the difference.
C
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My planned fix for this is to add an analog filter between the mic and the rig to roll off aggressively above 3 Khz.? Improving it at RF level would involve far more work where cooking up an active filter is easy and fun (for the twisted minds, anyway).
73/jeff/ac0c
alpha-charlie-zero-charlie
On 4/2/2024 1:49 PM, W7WRX wrote:
This makes sense.? A friend has the 32A, I have listed and watched its signal for years on scope.? It's always been super wide and always had some buckshot.? I assumed it was modified.
C
It does not make a material impact on the transmitted bandwidth in my testing.? I certainly would be interested to see if someone else has looked at the transmit bandwidth on their units.? Maybe there is something wrong with my HT-32A.
Regarding CR2, that seems more of a leveling action and has no sharpness by way of roll off at all.? And per 7-16 Crystal Filter Alignment item 3, it says "transmitter output should not drop BELOW 3dB at the extremes of the audio passband (650-3Khz).? My
claim is that there is no mechanism in the rig that provides a meaningful roll off above 3 Khz beyond a small number of dB per octave.
The measurements I published on the reflector May 10 2023 had this data:
8.7K @ -12 dB from peak amplitude (yellow trace)
6.8K @ -12 dB from peak amplitude (green trace)
So yes, there is a roll off.? But from a crystal BPF standpoint, the HT-32A I measured is really really wide by comparison.? I would be very interested in someone else making a similar measurement on their rig for a sanity check.?
--
73/jeff/ac0c
alpha-charlie-zero-charlie
73/jeff/ac0c
alpha-charlie-zero-charlie
On 4/2/2024 1:23 PM, waltcates wrote:
CR2 is the passband filter. Its adjustment is C121.
Walt Cates, WD0GOF
?
A majority of acceptance is not proof of correctness.
?
That's true Walt.? But if you sweep these filters, they don't provide passband attenuation on the transmitted sideband.? They do a fine job on the carrier and the opposite sideband, but don't do anything for the
occupied bandwidth of the transmitted signal.
I actually could not believe this was the case - and to that end, completely disassembled the filter modules on a spare HT-32 I had to check out what the SA was showing me.? I have plots & photos of that exercise
around here somewhere if someone is interested.?
73/jeff/ac0c
alpha-charlie-zero-charlie
On 4/2/2024 11:22 AM, waltcates wrote:
The 32 actually has 3 filters CR2, FL1 and FL2?
Walt Cates, WD0GOF
?
A majority of acceptance is not proof of correctness.
?
The HT-32 has no BPF in the classic sense.? Just some L/C type providing a pretty gentle roll off.?
73/jeff/ac0c
alpha-charlie-zero-charlie
On 4/2/2024 10:48 AM, Rick W4XA wrote:
The Drake TR-4 came with 2.1 kHz filters.? I replaced them in mine with the aftermarket Inrad 2.5kHz filters.
Not only do I get much better reports on the air but the receive fidelity is a LOT easier to listen to!
I get great audio reports with my HT-32B.? I think it's got a 3kHz filter in it?
I couldn't find the filter specs in the SR-400 manual.? I guess they really don't say what the BW? is. but it would seem to be somewhere around 2.3-2.5 kHz based on the shift in the carrier frequencies?? I guess the only way to know for sure would be to "sweep"
it.
--
73/Rick
W4XA
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I will answer my own question.? NO the cap is not an FP Style. I ordered a replacement, and it is MUCH larger. I cant find that can cap anywhere. I will have no choice but to mount new caps under the chassis.?
C
|
Chirp Chirp Chirp, geez.?
Hi Folks,
In the process of restoring a SR2K. In receive when I rotate the load control an oscillation / Chrip is heard on the speaker. This condition occur with or without HV.?
Thoughts Welcome,
dave
wa3gin
|
Re: SR2000 Cant Null carrier
Thank you for the suggestion.? The radio was working and done.? It then just the next day all the sudden had the carrier.? The trimmer was in fact bad and according to Walt's guide, this is common.
I have had this problem several times now on various rigs.? The Invader 2000 had this issue and only after I shot gunned the ENTIRE circuit, Resistors, trimmers, Diodes and caps, Did it start working again. The resistors did go way up in value.
Also had this problem with my Collins S line. The 32S3C had 1 watt of carrier.? I replaced the odd diode bridge with 4 1n5711s and I added a small ceramic cap and bingo it nulled.?
I found the exact model NPO trimmers on Ebay. I ordered 5.? Its going to be a week down time. They are in New Hampshire. Just about as far as you could possibly get from my QTH.
When they get here, I will get some new small hardware and install the trimmer. It will look like factory.? I will replace ALL of it.? Every part so it is all NEW.? ?Then, Cross my fingers and key it up.??
These things have not been on and used in maybe 40 years. They have put up a hell of a fight.? But they will both be expertly repaired and work better than new when I am complete. It's just going to take more time.
C
|
Hi Folks,
In the process of restoring a SR2K. In receive when I rotate the load control an oscillation / Chrip is heard on the speaker. This condition occur with or without HV.?
Thoughts Welcome,
dave
wa3gin
|
Hi Folks,
In the process of restoring a SR2K. In receive when I rotate the load control an oscillation / Chrip is heard on the speaker. This condition occur with or without HV.?
Thoughts Welcome,
dave
wa3gin
|
Re: SR2000 Cant Null carrier
This may be irrelevant to the SR-2000, I am not familiar with it. I
had a similar problem with a Drake T4XB, couldn't null the carrier. I
found, after considerable waste motion, the problem was wiring. A
previous owner had re-wired part of the balanced modulator. While the
wiring _looked_ perfectly fine, it was not. I got photographs of the
correct wiring from Garry Barrell (SK) who was the maven of Drake. Turns
out the the wires to the diode bridge were reversed. It was not the
polarity but the location of the wires that made the difference. The
stray capacitance was so different it put the trimming cap out of range.
I restored the original wiring and the null was perfect and right in the
center of the trimmer range.
Is it possible that something in this rig has changed? You might
need pix of the correct wiring to compare to yours.
Again, may be irrelevant to your problem but on my transmitter it
caused me to chase my tail for quite a while.
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On 4/2/2024 4:06 PM, W7WRX wrote: I cleaned and tightened everything including the bracket. No change.
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
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Re: SR2000 Cant Null carrier
I cleaned and tightened everything including the bracket. No change.?
I drilled the rivets and removed the old Trimmer. It was bad. It reads nothing on my LCR.?
New trimmer reads 4 to 26 pf.? Rated at 25pf.
I had to space it from the chassis. It is different.??
plugged back in. NO change.? I can adjust the trimmer and null .5w either way.? The pot and trimmer manipulation ends at 2w output.? That is for BOTH side bands LSB and USB
GRRRRR...? I am going to look for the exact trimmer now. If anyone has one please let me know!!!
I guess I am going to have to replace the diodes, resistors and the .005. Just gut it all and start over.? This is crazy. The rig was DONE and one the air working.
C
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Paul Christensen
Bill (Group Owner)
don Root
Dave Jordan