Re: Sx100 question on 50.5 kc alignment
Keith,
It seems to me you are going to need an RF probe on your VTVM to measure 1 volt RF. You can easily build your own single diode probe. Look on the internet for a simple circuit.
73
Scott
N6CIC
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Re: SR2000 Cant Null carrier
The mount is insulated so rivets dont ground the cap..?
The cap is not adjusting the circuit.? They are known to fail.??
I put a drop of dexoit on it last night as a last resort. It did not fix it this morning.?
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Re: Sx100 question on 50.5 kc alignment
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On Mon, Apr 1, 2024 at 7:07 PM, Keith <kd4avp@...> wrote: Ok that makes more sense to me now.
AGC was off.?
I will drop the output on the generator .
Will use my scope to get it just registering, then move it over to the T1 input point.?
This Heathkit is not as user friendly as I had hoped but should get me in the ballpark.?
I think learning to use what I have properly is my biggest challenge.
Will tackle it again later in the week.?
Thank you both for the guidance.?
I am learning a lot as I go thru this adventure.
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Re: Sx100 question on 50.5 kc alignment
I'm getting close to doING the same on my SX-100. So I'm interested in knowing your outcome. What is the peak to peak measurement of your input signal and is it 50 ohm terminated? And, what about your probes (10:1 or not)? -Drew
On Mon, Apr 1, 2024 at 5:25 PM, Keith <kd4avp@...> wrote: Apparently I only thought my alignment was successful.
Think I either interpreted something wrong or there is something more going on.?
Inputting a 50.5kc signal at T1 on pin number 1 as directed in the manual.?
I am using a Heathkit IG 5282 signal generator adjusted as close to 50.5kc I can get.
Used my oscilloscope to get that on target.?
Pulled the 1 osc conversion tube as recommended.?
Using my VTVM connected at point B (R48, R49 & C81 all connect on a terminal strip at this point), was monitoring the DC voltage.
I was adjusting T3, T4, T5 & T6 (all 50.5 IFs) to maintain 1 volt reading on the VTVM.
I never got anywhere close to 1 volt DC.
It was actually closer to 10 and 12 vdc.
What am I missing here?
I did manage to get it down to 7 volts but it was not completely stable there. But I did expect it to vary a little bit.
In my mind, I must have been thinking it should only vary by 1 volt....not actually be 1 volt.
Leaning on you guys with a better understanding of what I may be seeing here.?
Thanks!
Keith
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Re: Sx100 question on 50.5 kc alignment
Guess this old dog is not too old to keep learning. Definitely not what my work background has been. Just always had an interest in radios and hate to see these beautiful receivers just go to a junk pile. ? ?
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From: andrew griffith <agriffith@...>
Sent: Monday, April 1, 2024 10:23 PM
To: [email protected]; Keith <kd4avp@...>
Subject: Re: [HallicraftersRadios] Sx100 question on 50.5 kc alignment? You and me both, Keith -Drew ? On Mon, Apr 1, 2024 at 7:07 PM, Keith Ok that makes more sense to me now.
AGC was off.?
I will drop the output on the generator .
Will use my scope to get it just registering, then move it over to the T1 input point.?
This Heathkit is not as user friendly as I had hoped but should get me in the ballpark.?
I think learning to use what I have properly is my biggest challenge.
Will tackle it again later in the week.?
Thank you both for the guidance.?
I am learning a lot as I go thru this adventure.
|
The 150 filter is a little wider, a little better high frequency audio. It just sounds a little better.
Walt Cates, WD0GOF
?
A majority of acceptance is not proof of correctness.
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My SR400 schematic appears to indicate 1650 and 1652.8 kHz crystals.? FL1 is a 1650 6-pole filter.
What is the advantage of changing? to the filter and frequencies from the SR150?
--
73/Rick
W4XA
__________________________________
All posts are created using OpenSuSE Leap 15.5 x64 Linux
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My SR400 schematic appears to indicate 1650 and 1652.8 kHz crystals.? FL1 is a 1650 6-pole filter.
What is the advantage of changing? to the filter and frequencies from the SR150?
--
73/Rick
W4XA
__________________________________
All posts are created using OpenSuSE Leap 15.5 x64 Linux
|
Re: SR2000 Cant Null carrier
Certainly,? you might not want to use a drill.? Instead use a dremel?tool and have a running shop vac?hose next to the dremel to suck up all of the metal filings.
Good Luck, dave wa3gin
On Mon, Apr 1, 2024 at 11:11?PM W7WRX < clark@...> wrote:
Ok.? I need to measure the one I have to make sure it will be a direct fit.? Nervous about drilling the rivets.? Don't have much of a choice I guess.
C
Hey,
Take pics of the trimmer upgrade.
Thanks,
dave
wa3gin
On Mon, Apr 1, 2024 at 9:21?PM W7WRX < clark@...> wrote:
Came home and fired the rig up. let it run for an hour. Found a 10 to 15 W carrier on Both side bands.
Attempted to NULL the carrier.? The POT works and did null it down to 3W.?
The Trimmer Cap only has an effect of maybe .5w.? ?
I clipped a counter to the test point of the carrier xtals and could not believe it. Both xtals had moved in the right direction!? ?
What the heck.? They are both spot on now.? 1648.550. I can adjust up and down from there. That xtal was best case 1648.4?
I guess the trimmer failed???? ?
I hate to have to change it. its riveted in.? I have a replacement 5 to 25PF trimmer.? Also new modern diodes. I guess I will rebuild this circuit now.
C
|
Re: SR2000 Cant Null carrier
Ok.? I need to measure the one I have to make sure it will be a direct fit.? Nervous about drilling the rivets.? Don't have much of a choice I guess.
C
Hey,
Take pics of the trimmer upgrade.
Thanks,
dave
wa3gin
On Mon, Apr 1, 2024 at 9:21?PM W7WRX < clark@...> wrote:
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Show quoted text
Came home and fired the rig up. let it run for an hour. Found a 10 to 15 W carrier on Both side bands.
Attempted to NULL the carrier.? The POT works and did null it down to 3W.?
The Trimmer Cap only has an effect of maybe .5w.? ?
I clipped a counter to the test point of the carrier xtals and could not believe it. Both xtals had moved in the right direction!? ?
What the heck.? They are both spot on now.? 1648.550. I can adjust up and down from there. That xtal was best case 1648.4?
I guess the trimmer failed???? ?
I hate to have to change it. its riveted in.? I have a replacement 5 to 25PF trimmer.? Also new modern diodes. I guess I will rebuild this circuit now.
C
|
Re: Sx100 question on 50.5 kc alignment
Ok that makes more sense to me now.
AGC was off.?
I will drop the output on the generator .
Will use my scope to get it just registering, then move it over to the T1 input point.?
This Heathkit is not as user friendly as I had hoped but should get me in the ballpark.?
I think learning to use what I have properly is my biggest challenge.
Will tackle it again later in the week.?
Thank you both for the guidance.?
I am learning a lot as I go thru this adventure.
|
Re: Sx100 question on 50.5 kc alignment
Thanks Dan, I missed that one.
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?Test point B is DC. Keeping the displayed voltage around 1 volt or so isn’t super critical during the 50.5 alignment ?but, in general, you usually want to keep the injected and observed voltages pretty minimal to get the best alignment, unless
the manual calls for a specific voltage or level. Pay attention to your AGC switch. I don’t quickly remember if the manual says to have it on or off for the 50.5 alignment (probably off, I think) but on or off will make a huge difference on the prevailing
voltage at test point B so make sure yours is set right.
Can you reduce the level on your sig gen? If you can’t get down to 1-2 volts or so you probably are injecting too much 50.5 kHz or your AGC switch is not set right. You should be able to keep test point B easily in a ~1-3 VDC range and peak T3-T6 from
there.
I keep an old HP-606A around just for the 50 kHz Drakes and Hallicrafters. I set and confirm a 50.5 output using a scope with a counter function. The 606 is dead stable and warms the shop in the winter.
Dan
WB4GRA
On Apr 1, 2024, at 8:37?PM, waltcates <cateswa@...> wrote:
?
You are getting DC and AC mixed.
The 1 volt rms is the ac signal.
The dc component (10 to 12 volts) is the dc bias developed by the detector diode tube.
Go back to test point, set your meter on ac and try again.
Walt Cates, WD0GOF
?
A majority of acceptance is not proof of correctness.
Apparently I only thought my alignment was successful.
Think I either interpreted something wrong or there is something more going on.?
Inputting a 50.5kc signal at T1 on pin number 1 as directed in the manual.?
I am using a Heathkit IG 5282 signal generator adjusted as close to 50.5kc I can get.
Used my oscilloscope to get that on target.?
Pulled the 1 osc conversion tube as recommended.?
Using my VTVM connected at point B (R48, R49 & C81 all connect on a terminal strip at this point), was monitoring the DC voltage.
I was adjusting T3, T4, T5 & T6 (all 50.5 IFs) to maintain 1 volt reading on the VTVM.
I never got anywhere close to 1 volt DC.
It was actually closer to 10 and 12 vdc.
What am I missing here?
I did manage to get it down to 7 volts but it was not completely stable there. But I did expect it to vary a little bit.
In my mind, I must have been thinking it should only vary by 1 volt....not actually be 1 volt.
Leaning on you guys with a better understanding of what I may be seeing here.?
Thanks!
Keith
|
Re: Sx100 question on 50.5 kc alignment
? Test point B is DC. Keeping the displayed voltage around 1 volt or so isn’t super critical during the 50.5 alignment ?but, in general, you usually want to keep the injected and observed voltages pretty minimal to get the best alignment, unless the manual calls for a specific voltage or level. Pay attention to your AGC switch. I don’t quickly remember if the manual says to have it on or off for the 50.5 alignment (probably off, I think) but on or off will make a huge difference on the prevailing voltage at test point B so make sure yours is set right.
Can you reduce the level on your sig gen? If you can’t get down to 1-2 volts or so you probably are injecting too much 50.5 kHz or your AGC switch is not set right. You should be able to keep test point B easily in a ~1-3 VDC range and peak T3-T6 from there.
I keep an old HP-606A around just for the 50 kHz Drakes and Hallicrafters. I set and confirm a 50.5 output using a scope with a counter function. The 606 is dead stable and warms the shop in the winter.
Dan WB4GRA
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On Apr 1, 2024, at 8:37?PM, waltcates <cateswa@...> wrote:
?
You are getting DC and AC mixed.
The 1 volt rms is the ac signal.
The dc component (10 to 12 volts) is the dc bias developed by the detector diode tube.
Go back to test point, set your meter on ac and try again.
Walt Cates, WD0GOF
?
A majority of acceptance is not proof of correctness.
Apparently I only thought my alignment was successful.
Think I either interpreted something wrong or there is something more going on.?
Inputting a 50.5kc signal at T1 on pin number 1 as directed in the manual.?
I am using a Heathkit IG 5282 signal generator adjusted as close to 50.5kc I can get.
Used my oscilloscope to get that on target.?
Pulled the 1 osc conversion tube as recommended.?
Using my VTVM connected at point B (R48, R49 & C81 all connect on a terminal strip at this point), was monitoring the DC voltage.
I was adjusting T3, T4, T5 & T6 (all 50.5 IFs) to maintain 1 volt reading on the VTVM.
I never got anywhere close to 1 volt DC.
It was actually closer to 10 and 12 vdc.
What am I missing here?
I did manage to get it down to 7 volts but it was not completely stable there. But I did expect it to vary a little bit.
In my mind, I must have been thinking it should only vary by 1 volt....not actually be 1 volt.
Leaning on you guys with a better understanding of what I may be seeing here.?
Thanks!
Keith
|
Re: SR2000 Cant Null carrier
Hello C, I don’t know anything about the rig, but with that cap riveted in, if you think that cap is shot but not certain, perhaps? jump it somehow with a good cap of some reasonable value, and see what happens.. just an idea , but I don’t understand the circuit. ?,, ahhh maybe a bad riveted connection… HooNose ?
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From: [email protected] [mailto:[email protected]] On Behalf Of W7WRX
Sent: Monday, April 1, 2024 9:21 PM
To: [email protected]
Subject: [HallicraftersRadios] SR2000 Cant Null carrier? Came home and fired the rig up. let it run for an hour. Found a 10 to 15 W carrier on Both side bands.
Attempted to NULL the carrier.? The POT works and did null it down to 3W.?
The Trimmer Cap only has an effect of maybe .5w.? ?
I clipped a counter to the test point of the carrier xtals and could not believe it. Both xtals had moved in the right direction!? ?
What the heck.? They are both spot on now.? 1648.550. I can adjust up and down from there. That xtal was best case 1648.4?
I guess the trimmer failed???? ?
I hate to have to change it. its riveted in.? I have a replacement 5 to 25PF trimmer.? Also new modern diodes. I guess I will rebuild this circuit now.
C ? -- don??? va3drl
|
Re: SR2000 Cant Null carrier
Hey,
Take pics of the trimmer upgrade.
Thanks, dave wa3gin
On Mon, Apr 1, 2024 at 9:21?PM W7WRX < clark@...> wrote: Came home and fired the rig up. let it run for an hour. Found a 10 to 15 W carrier on Both side bands.
Attempted to NULL the carrier.? The POT works and did null it down to 3W.?
The Trimmer Cap only has an effect of maybe .5w.? ?
I clipped a counter to the test point of the carrier xtals and could not believe it. Both xtals had moved in the right direction!? ?
What the heck.? They are both spot on now.? 1648.550. I can adjust up and down from there. That xtal was best case 1648.4?
I guess the trimmer failed???? ?
I hate to have to change it. its riveted in.? I have a replacement 5 to 25PF trimmer.? Also new modern diodes. I guess I will rebuild this circuit now.
C
|
Came home and fired the rig up. let it run for an hour. Found a 10 to 15 W carrier on Both side bands.
Attempted to NULL the carrier.? The POT works and did null it down to 3W.?
The Trimmer Cap only has an effect of maybe .5w.? ?
I clipped a counter to the test point of the carrier xtals and could not believe it. Both xtals had moved in the right direction!? ?
What the heck.? They are both spot on now.? 1648.550. I can adjust up and down from there. That xtal was best case 1648.4?
I guess the trimmer failed???? ?
I hate to have to change it. its riveted in.? I have a replacement 5 to 25PF trimmer.? Also new modern diodes. I guess I will rebuild this circuit now.
C
|
Re: Sx100 question on 50.5 kc alignment
You are getting DC and AC mixed.
The 1 volt rms is the ac signal.
The dc component (10 to 12 volts) is the dc bias developed by the detector diode tube.
Go back to test point, set your meter on ac and try again.
Walt Cates, WD0GOF
?
A majority of acceptance is not proof of correctness.
toggle quoted message
Show quoted text
Apparently I only thought my alignment was successful.
Think I either interpreted something wrong or there is something more going on.?
Inputting a 50.5kc signal at T1 on pin number 1 as directed in the manual.?
I am using a Heathkit IG 5282 signal generator adjusted as close to 50.5kc I can get.
Used my oscilloscope to get that on target.?
Pulled the 1 osc conversion tube as recommended.?
Using my VTVM connected at point B (R48, R49 & C81 all connect on a terminal strip at this point), was monitoring the DC voltage.
I was adjusting T3, T4, T5 & T6 (all 50.5 IFs) to maintain 1 volt reading on the VTVM.
I never got anywhere close to 1 volt DC.
It was actually closer to 10 and 12 vdc.
What am I missing here?
I did manage to get it down to 7 volts but it was not completely stable there. But I did expect it to vary a little bit.
In my mind, I must have been thinking it should only vary by 1 volt....not actually be 1 volt.
Leaning on you guys with a better understanding of what I may be seeing here.?
Thanks!
Keith
|
Sx100 question on 50.5 kc alignment
Apparently I only thought my alignment was successful.
Think I either interpreted something wrong or there is something more going on.?
Inputting a 50.5kc signal at T1 on pin number 1 as directed in the manual.?
I am using a Heathkit IG 5282 signal generator adjusted as close to 50.5kc I can get.
Used my oscilloscope to get that on target.?
Pulled the 1 osc conversion tube as recommended.?
Using my VTVM connected at point B (R48, R49 & C81 all connect on a terminal strip at this point), was monitoring the DC voltage.
I was adjusting T3, T4, T5 & T6 (all 50.5 IFs) to maintain 1 volt reading on the VTVM.
I never got anywhere close to 1 volt DC.
It was actually closer to 10 and 12 vdc.
What am I missing here?
I did manage to get it down to 7 volts but it was not completely stable there. But I did expect it to vary a little bit.
In my mind, I must have been thinking it should only vary by 1 volt....not actually be 1 volt.
Leaning on you guys with a better understanding of what I may be seeing here.?
Thanks!
Keith
|
HT-37 CW fall time <1mS - SOLVED
Traced the keying line through the rig and the critical waveform
behavior for the trailing edge is the cutoff of the crystal
oscillator/mixer combo.? The drop onset of cutoff for the other
stages was extremely slow by comparison and could not have been
contributory.?
An example of the fall time issue mentioned originally is shown
in this scope shot.? Notice the near vertical drop in amplitude
vs. time as the red arrow indicates.
Taking a closer look at the oscillator, with injection level set
to 0.5V per manual, I would get the truncated edge on 40m.? If I
increased the injection level amplitude via C66 trimmer to about
1.3V, then the keying waveform reverted to what I saw on other
bands - a rise time still relatively short (around 2-3 mS) but not
like the 40m, where the drop being almost
instantaneous by comparison.?
The CW rise/fall (for all bands) can be adjusted by increasing
the values of these two caps:
Rise - C204 - 0.1uF stock.? I added a 0.47 uF in parallel (0.475
uF total)
Fall - C70 - 0.005 stock.? I added a 0.47 uF in parallel (0.57 uF
total)
The combination of these two changes resulted in a roughly 6 mS
rise and fall time on the CW edge.?
Separately, I noticed there is a bit of first-dit-truncation -
but it's possible that may have been the case before I made the
changes.?
I'll run the rig on 40m CW for some rag chew over the next week
and see how the signal reports are.? But judging from the
waveform, I don't expect to get any key-click reports.?
73/jeff/ac0c
alpha-charlie-zero-charlie
On 3/31/2024 9:17 PM, Jeff AC0C wrote:
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I have a HT-37 on the bench that is complete from recap and
alignment.?
But I have noticed the fall time on CW is nearly zero; it's well
under 1
mS.? Before I start tracking this down and looking for a way to
stretch
that fall time, I wanted to see if maybe someone else had
encountered
and resolved this same issue.
Appreciate any advice or suggestions.
--
73/jeff/ac0c
alpha-charlie-zero-charlie
|
The specs on the filter are rather embedded.
The transmitter audio response for the 150 is 600Hz to 2800Hz.
The transmitter audio response for the 400 and 2000 is 500Hz to 2400Hz.
You can play around with the math and get the IF frequencies. Just remember the stated response ends ie 600 and 2800 are the shoulders of the passband and are 3db down.
Walt Cates, WD0GOF
?
A majority of acceptance is not proof of correctness.
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Looks like not much would be needed.
The Xtals are 1648.1 and 1651.7 in the SR150.? ?I do not know the difference in the FL1.? ?It does not say the bandwidth in the 150 manual or schematic.? ?I suspect it is wider?
C
I have not seen any documentation on the swap-out.
I also have not done the mod. I would imagine the mod to the 400 is pretty much plug and play the 150 and 400 use the same input and output tuning coils.?
The 2000 however has a different output loading coil. That could cause some problems. Just be aware, it may not be plug and play in the 2000.?
Perhaps someone on the forum has done the mod on the 2000 and will jump in.
Walt Cates, WD0GOF
?
A majority of acceptance is not proof of correctness.
Is there anything written on how to swap the FL1 and crystals?
TNX - WS4AM
|
Looks like not much would be needed.
The Xtals are 1648.1 and 1651.7 in the SR150.? ?I do not know the difference in the FL1.? ?It does not say the bandwidth in the 150 manual or schematic.? ?I suspect it is wider?
C
toggle quoted message
Show quoted text
I have not seen any documentation on the swap-out.
I also have not done the mod. I would imagine the mod to the 400 is pretty much plug and play the 150 and 400 use the same input and output tuning coils.?
The 2000 however has a different output loading coil. That could cause some problems. Just be aware, it may not be plug and play in the 2000.?
Perhaps someone on the forum has done the mod on the 2000 and will jump in.
Walt Cates, WD0GOF
?
A majority of acceptance is not proof of correctness.
Is there anything written on how to swap the FL1 and crystals?
TNX - WS4AM
|
KN6WFM (Drew)
waltcates
Rick W7IMM
Dave Jordan
don Root