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Greetings fellow QRPLabs enthusiasts:
?
I finally finished assembling my QCX kit (not the + version) after having it on my bench for several years.?
?
How exciting it was to power it up and adjust the contrast to see the screen this afternoon!
?
Unfortunately, I could not remember what band it was for (been awhile and at my age I don’t remember what I ate for breakfast HA!).? So I checked the caps C25 and C26 and saw 680 for the label, so I concluded that it was for 40 meters.
?
So I started the alignment procedure, (page 63, section 3.70):
?
I chose 40 meters for the band, and attempted to peak the BPF (page 64).? I was unable to obtain any reading regardless of the C1 trimmer adjustment.? ?The value showed 0.
?
I did not want to immediately start messing with that nasty T1 toroid, so instead I decided to do some voltage checking to see if I could find any issues.
?
I started on pager 124 with suggested voltages for T1, using my DVM.? I noted that T1 pins 5, 6, 7 and 8 were showing about 1 volt less than suggested….1.4V.
?
Then I focused on IC5 voltages and noted the same…the suggested voltages around 2.26 to 2.64 volts were all showing about 1V less when measured.? I noted the same for IC6 and IC7.
?
Also checked Clk 0 and Clk 1 voltages, and found them to be about 1V less than suggested values.
?
This was observed regardless of powering the unit with a 12V battery or a 9V battery…same readings.
?
Before I proceed further, I wanted to check and see if anyone can recommend additional investigation.
?
Some thoughts:
- Problem with the soldering for C1? ?I double-checked for bad/cold joints, no issues noted
- Problem with the soldering for T1? ?I was very careful on counting the windings, triple-checked.? The connection must be good across all windings if I am getting voltages on it, right??
The solder adhered, so I must have removed the enamel with the heat.
- Problem with the voltage regulator?? Maybe that’s why the voltages are showing 1 V less?
?
Thanks in advance for the help.
?
Mark Lunday, WD4ELG
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Hi Mark. First, I would count the turns on T1. Fron that you should be able to determine the band it was wound for. You can also count the turns on the other toroid's. Check each result with the manual. Once you have determined the correct band, it may be 40 meters, but it could be another band. Next, check for continuity on T1. Because so many problems develop from poor soldering on T1, I would reflow each of the connections.
Then with the correct band dialed in, start the set up process again.?
Tell us what you learned. Hopefully you'll be able to get it on the air.
Gary W0CKI, ( I have had several of them, all types)
-----Original Message-----
From: Mark, WD4ELG <wd4elg@...>
To: [email protected] < [email protected]>
Sent: Wed, Jan 25, 2023 5:57 pm
Subject: [QRPLabs] Problems with QCX build, guidance needed please
Greetings fellow QRPLabs enthusiasts:
?
I finally finished assembling my QCX kit (not the + version) after having it on my bench for several years.?
?
How exciting it was to power it up and adjust the contrast to see the screen this afternoon!
?
Unfortunately, I could not remember what band it was for (been awhile and at my age I don’t remember what I ate for breakfast HA!).? So I checked the caps C25 and C26 and saw 680 for the label, so I concluded that it was for 40 meters.
?
So I started the alignment procedure, (page 63, section 3.70):
?
I chose 40 meters for the band, and attempted to peak the BPF (page 64).? I was unable to obtain any reading regardless of the C1 trimmer adjustment.? ?The value showed 0.
?
I did not want to immediately start messing with that nasty T1 toroid, so instead I decided to do some voltage checking to see if I could find any issues.
?
I started on pager 124 with suggested voltages for T1, using my DVM.? I noted that T1 pins 5, 6, 7 and 8 were showing about 1 volt less than suggested….1.4V.
?
Then I focused on IC5 voltages and noted the same…the suggested voltages around 2.26 to 2.64 volts were all showing about 1V less when measured.? I noted the same for IC6 and IC7.
?
Also checked Clk 0 and Clk 1 voltages, and found them to be about 1V less than suggested values.
?
This was observed regardless of powering the unit with a 12V battery or a 9V battery…same readings.
?
Before I proceed further, I wanted to check and see if anyone can recommend additional investigation.
?
Some thoughts:
- Problem with the soldering for C1? ?I double-checked for bad/cold joints, no issues noted
- Problem with the soldering for T1? ?I was very careful on counting the windings, triple-checked.? The connection must be good across all windings if I am getting voltages on it, right??
The solder adhered, so I must have removed the enamel with the heat.
- Problem with the voltage regulator?? Maybe that’s why the voltages are showing 1 V less?
?
Thanks in advance for the help.
?
Mark Lunday, WD4ELG
?
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Hi Mark. On your voltage issues, lift T1 wire number 5 from the board and re-measure voltage at wire 6 or 7 (they are connected together). If the voltage is still low, lift T1 wire number 8 from the board and measure again at wire 6 or 7. If still low, check resistors R1 and R2. But, if voltage is now closer to 2.5v with wires 5 and 8 lifted, then it's possible there is a problem with IC4. But it's also possible that something else is loading it down, like IC5. So, next reconnect?the T1 wires in hoiles 5 and 8 and lift one leg each of R5, R6, R8 and R9 and re-check the voltage at T1 wire 6 or 7. If it is still low at this point, I suspect you will need to change IC4.?
Good luck. Hope this helps ... 73 .. Ron
On Wed, Jan 25, 2023 at 6:16 PM Gary Bernard via <garybernard2= [email protected]> wrote:
Hi Mark. First, I would count the turns on T1. Fron that you should be able to determine the band it was wound for. You can also count the turns on the other toroid's. Check each result with the manual. Once you have determined the correct band, it may be 40 meters, but it could be another band. Next, check for continuity on T1. Because so many problems develop from poor soldering on T1, I would reflow each of the connections.
Then with the correct band dialed in, start the set up process again.?
Tell us what you learned. Hopefully you'll be able to get it on the air.
Gary W0CKI, ( I have had several of them, all types)
-----Original Message-----
From: Mark, WD4ELG < wd4elg@...>
To: [email protected] < [email protected]>
Sent: Wed, Jan 25, 2023 5:57 pm
Subject: [QRPLabs] Problems with QCX build, guidance needed please
Greetings fellow QRPLabs enthusiasts:
?
I finally finished assembling my QCX kit (not the + version) after having it on my bench for several years.?
?
How exciting it was to power it up and adjust the contrast to see the screen this afternoon!
?
Unfortunately, I could not remember what band it was for (been awhile and at my age I don’t remember what I ate for breakfast HA!).? So I checked the caps C25 and C26 and saw 680 for the label, so I concluded that it was for 40 meters.
?
So I started the alignment procedure, (page 63, section 3.70):
?
I chose 40 meters for the band, and attempted to peak the BPF (page 64).? I was unable to obtain any reading regardless of the C1 trimmer adjustment.? ?The value showed 0.
?
I did not want to immediately start messing with that nasty T1 toroid, so instead I decided to do some voltage checking to see if I could find any issues.
?
I started on pager 124 with suggested voltages for T1, using my DVM.? I noted that T1 pins 5, 6, 7 and 8 were showing about 1 volt less than suggested….1.4V.
?
Then I focused on IC5 voltages and noted the same…the suggested voltages around 2.26 to 2.64 volts were all showing about 1V less when measured.? I noted the same for IC6 and IC7.
?
Also checked Clk 0 and Clk 1 voltages, and found them to be about 1V less than suggested values.
?
This was observed regardless of powering the unit with a 12V battery or a 9V battery…same readings.
?
Before I proceed further, I wanted to check and see if anyone can recommend additional investigation.
?
Some thoughts:
- Problem with the soldering for C1?? I double-checked for bad/cold joints, no issues noted
- Problem with the soldering for T1?? I was very careful on counting the windings, triple-checked.? The connection must be good across all windings if I am getting voltages on it, right??
The solder adhered, so I must have removed the enamel with the heat.
- Problem with the voltage regulator?? Maybe that’s why the voltages are showing 1 V less?
?
Thanks in advance for the help.
?
Mark Lunday, WD4ELG
?
|
Gary and Ron, thanks for the help; I greatly appreciate it.?
?
Made some progress tonight:
?
Took another look with DVM and magnifier at T1, and noted that several of the wires on T1 did not have solid contact due to enamel – fixed!
Counted the turns on T1 and confirmed that I wired it for 40 meters, which matches the capacitors in the filter.
Powered up the unit and went into menu 8.7 for Peak BPF, and saw ? deflection/level.? C1 adjustment had no impact on the level, but I thought that since I had good indication that everything should be OK.
Went to menu 8.8 ?I-Q bal and saw a minimal deflection.
Went to menu 8.9 for Phase Lo and saw no deflection.
Went to menu 8.10 and saw no deflection.
?
So everything should be good for initial alignment (according to my understanding).
?
Hooked up the 40 meter dipole antenna and plugged in some earbuds…..nothing heard.? ARGH!
?
Pressed down on the CW microswitch and listened on a separate receiver, no output signal heard.? ARGH!
?
Went to menu #9 to use some of the test equipment.
Menu 9.3, value is 0 regardless of the RF gain knob setting.? Same with value for 9.4,? Not good.
Looking at page 104, section 5.1 of the Block diagram – doesn’t really help me much with further investigation.
Looking at page 105, the complete schematic looks impressive, but it also doesn’t help me much with further investigation.
?
So I am dealing with two separate issues:? CW microswitch is not activating transmit, and bigger issue is no audio output to the headphones.
?
Ron, before I replace IC5 (because I am still seeing the same voltage values as before), I don’t understand how this voltage would cause the issues I am seeing now.??
?
(Not sure if Hans provides IC5 or if I should just order a new kit (is the QCX+ made with the same IC5?)
?
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Mark. On 8.7 there should also be a number associated with the displayed deflection level. The reading increases on the scale until the scan number goes up to its highest value. This is typically 7 or 8 on the 8.7 adjustment. If that is the case then audio is good all the way to the IQ balance pot. If not, the problem can be anywhere including the lowpass filter.?
8.8, 8.9 and 8.10 are dependent on the setting of the volume control. On those measurements you are looking for a null so set the volume to get a reading of 8 or 9 to start with and adjust till those numbers drop to the lowest values. If you get good numbers on 8.7 above but minimal deflection at all volume levels on those three it means there is a problem in the audio chain somewhere after the IQ balance pot.?
The problem with no power output is usually associated with not getting all the enamel off L1,2, 3 or 4. And problems with L1-L3 can also affect the test signals used in the adjustments in the above paragraphs.?
73… Ron
On Thu, Jan 26, 2023 at 18:42 Mark, WD4ELG < wd4elg@...> wrote:
Gary and Ron, thanks for the help; I greatly appreciate it.?
?
Made some progress tonight:
?
Took another look with DVM and magnifier at T1, and noted that several of the wires on T1 did not have solid contact due to enamel – fixed!
Counted the turns on T1 and confirmed that I wired it for 40 meters, which matches the capacitors in the filter.
Powered up the unit and went into menu 8.7 for Peak BPF, and saw ? deflection/level.? C1 adjustment had no impact on the level, but I thought that since I had good indication that everything should be OK.
Went to menu 8.8 ?I-Q bal and saw a minimal deflection.
Went to menu 8.9 for Phase Lo and saw no deflection.
Went to menu 8.10 and saw no deflection.
?
So everything should be good for initial alignment (according to my understanding).
?
Hooked up the 40 meter dipole antenna and plugged in some earbuds…..nothing heard.? ARGH!
?
Pressed down on the CW microswitch and listened on a separate receiver, no output signal heard.? ARGH!
?
Went to menu #9 to use some of the test equipment.
Menu 9.3, value is 0 regardless of the RF gain knob setting.? Same with value for 9.4,? Not good.
Looking at page 104, section 5.1 of the Block diagram – doesn’t really help me much with further investigation.
Looking at page 105, the complete schematic looks impressive, but it also doesn’t help me much with further investigation.
?
So I am dealing with two separate issues:? CW microswitch is not activating transmit, and bigger issue is no audio output to the headphones.
?
Ron, before I replace IC5 (because I am still seeing the same voltage values as before), I don’t understand how this voltage would cause the issues I am seeing now.??
?
(Not sure if Hans provides IC5 or if I should just order a new kit (is the QCX+ made with the same IC5?)
?
|
Also check for continuity from the center conductor of the antenna bnc connector through L3. If you don’t have continuity then you probably have not adequately removed the enamel from those torroids. Check L4 also.
toggle quoted message
Show quoted text
On Jan 26, 2023, at 6:42 PM, Mark, WD4ELG <wd4elg@...> wrote:
?
Gary and Ron, thanks for the help; I greatly appreciate it.?
?
Made some progress tonight:
?
Took another look with DVM and magnifier at T1, and noted that several of the wires on T1 did not have solid contact due to enamel – fixed!
Counted the turns on T1 and confirmed that I wired it for 40 meters, which matches the capacitors in the filter.
Powered up the unit and went into menu 8.7 for Peak BPF, and saw ? deflection/level.? C1 adjustment had no impact on the level, but I thought that since I had good indication that everything should be OK.
Went to menu 8.8 ?I-Q bal and saw a minimal deflection.
Went to menu 8.9 for Phase Lo and saw no deflection.
Went to menu 8.10 and saw no deflection.
?
So everything should be good for initial alignment (according to my understanding).
?
Hooked up the 40 meter dipole antenna and plugged in some earbuds…..nothing heard.? ARGH!
?
Pressed down on the CW microswitch and listened on a separate receiver, no output signal heard.? ARGH!
?
Went to menu #9 to use some of the test equipment.
Menu 9.3, value is 0 regardless of the RF gain knob setting.? Same with value for 9.4,? Not good.
Looking at page 104, section 5.1 of the Block diagram – doesn’t really help me much with further investigation.
Looking at page 105, the complete schematic looks impressive, but it also doesn’t help me much with further investigation.
?
So I am dealing with two separate issues:? CW microswitch is not activating transmit, and bigger issue is no audio output to the headphones.
?
Ron, before I replace IC5 (because I am still seeing the same voltage values as before), I don’t understand how this voltage would cause the issues I am seeing now.??
?
(Not sure if Hans provides IC5 or if I should just order a new kit (is the QCX+ made with the same IC5?)
?
|
Ron, the value for 8.7 is at 6.? Changing C1 has no effect upon the value.? I will experiment with 8.8 through 8.10 and report back.
Gary, I will check for continuity as you suggested and report back.
Mark Lunday
WD4ELG
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Mark, are you hearing when you adjust the BPF?
-----Original Message-----
From: Mark, WD4ELG <wd4elg@...>
To: [email protected]
Sent: Thu, Jan 26, 2023 10:12 pm
Subject: Re: [QRPLabs] Problems with QCX build, guidance needed please
Ron, the value for 8.7 is at 6.? Changing C1 has no effect upon the value.? I will experiment with 8.8 through 8.10 and report back.
Gary, I will check for continuity as you suggested and report back.
Mark Lunday
WD4ELG
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Mark, the level 6 BPF with no movement when adjusting C1 suggests that one or both ends of the large winding on T1 are not making contact.?
Ron
On Fri, Jan 27, 2023 at 09:02 Gary Bernard via <garybernard2= [email protected]> wrote:
Mark, are you hearing when you adjust the BPF?
-----Original Message-----
From: Mark, WD4ELG < wd4elg@...>
To: [email protected]
Sent: Thu, Jan 26, 2023 10:12 pm
Subject: Re: [QRPLabs] Problems with QCX build, guidance needed please
Ron, the value for 8.7 is at 6.? Changing C1 has no effect upon the value.? I will experiment with 8.8 through 8.10 and report back.
Gary, I will check for continuity as you suggested and report back.
Mark Lunday
WD4ELG
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Gary, no audio at all.
Ron, I will re-check again the large windings on T1 to confirm connectivity.
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Check each connection on the volume control. That can be a problem also. Did you have continuity from center pin on the BNC through L3?
-----Original Message-----
From: Mark, WD4ELG <wd4elg@...>
To: [email protected]
Sent: Fri, Jan 27, 2023 12:55 pm
Subject: Re: [QRPLabs] Problems with QCX build, guidance needed please
Gary, no audio at all.
Ron, I will re-check again the large windings on T1 to confirm connectivity.
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Thanks again for the help. Steps taken:
- Confirmed connectivity from center of BNC through L1, L2 and L3 using DVM
- Resoldered 1 & 2 taps for T1, and confirmed connectivity using DVM
- Went into alignment menu 8.7, adjusted C1 for maximum value.? I was able to get almost full indication, at setting of 4 (attached pic).? The value did not seem to change even when I was able to get the deflection to near maximum...it remained between 4 and 6.
- Revisited 8.8 through 8.10 alignment menu items, saw some minimal movement on the scale (assuming this is normal) but very low levels, so this should be good to go.(low values)
Still no audio output, tried several different headsets/earbuds. Still no TX when pressing down on the microswitch.
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When you adjust the BPF do you hear a tone?
toggle quoted message
Show quoted text
On Jan 27, 2023, at 1:51 PM, Mark, WD4ELG <wd4elg@...> wrote:
?Thanks again for the help. Steps taken:
- Confirmed connectivity from center of BNC through L1, L2 and L3 using DVM
- Resoldered 1 & 2 taps for T1, and confirmed connectivity using DVM
- Went into alignment menu 8.7, adjusted C1 for maximum value.? I was able to get almost full indication, at setting of 4 (attached pic).? The value did not seem to change even when I was able to get the deflection to near maximum...it remained between 4 and 6.
- Revisited 8.8 through 8.10 alignment menu items, saw some minimal movement on the scale (assuming this is normal) but very low levels, so this should be good to go.(low values)
Still no audio output, tried several different headsets/earbuds. Still no TX when pressing down on the microswitch. <QCX1.jpeg>
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Hi Mark,
Try resetting the QCX. You find the reset in the ?other“ menu point. Use a 50Ohm Dummy load and go through the alignment menu points again. I had a similar problem. Make sure that when under menu point 8.10 that the volume is at 11. Then you minimize the amplitude. This did the trick for me. I could then hear morse code on the frequency.
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Gary - no audio from the BPF
p.pippi, thanks for that info.? Reset did nothing to help.
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Check all the connections at the volume control. That’s a tricky install as you have to bend the tabs. Check the control itself with a VOM DVM. There’s 2 resistors above the display, make sure you have the correct ones installed.
toggle quoted message
Show quoted text
On Jan 27, 2023, at 5:31 PM, Mark, WD4ELG <wd4elg@...> wrote:
?Gary - no audio from the BPF
p.pippi, thanks for that info.? Reset did nothing to help.
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Ronald Taylor
Pier HB9IIA