开云体育

ctrl + shift + ? for shortcuts
© 2025 开云体育
  1. K1elsystems
  2. Topics

Help troubleshooting OpenQrp 40M please

 

So I have started to build this kit I had tucked away for many years.? I have a DMM, scope (rigol), a tinysa and some other things.? Here is the state of things;
?
I have built many kits before and my soldering skills are pretty good.? I have inspected for cold or shorted contacts.? I have now just completed step 13 the PSOC.? PSOC Checkout is good.? All steps prior to 13 checked out as the manual stated, with one minor exception.? Probably just a misunderstanding on my part.??
?
Step 11 says "you will see the keyed 12 volt line turn on and off..."? i have keyer mode set to sup and when I key i see square wave (dits) but these are 7.5vpp.? I believe that is because zd1 is clamping the 12v line.? I think this part is working ok and not impacting my current situation.? Your thoughts please?
?
All the above is with the keyer SUP selected.? If I select KEY, which is actually what I want as I use a straight key, the keyed 12v does not work.? I dont know what to think about this ???
?
Now, the current issue.? Step 13 psoc complete and working.? Now is the vfo calibration.? I do not have ct3 thus did not install.? My vfo min was about 7150, so i had to add 3 windings and now it is at 7005 which is great for me as I never go that low in band anyway.? Vfo on lcd is working great, with 10k 1 turn currently installed per directions.
?
Here is a pic fro scope tp4.? I see the same keyed or not keyed, seems fine to me?
?
I am seeing 2.05mhz at 12.5vpp.? I also ched this with tinySa and is shows 2.061mhz at -70db.? So I believe all of this confirms the vfo section is good?
?
I believe the vfo buffer is good as the vfo displays and tuning up and down works and is stable.
?
Next it says check the vfo injection to the ne602 u1.? U1 pin 1 shows 256mv 2.06mhz signal on pin 1.? So I think it is good so far?
?
Now next steps are to be tested key down.? So in SUP key mode, keydown.? On R4 I see 5.6v nice clean square wave.? Q3 and Q4 also show square wave diff volts.? Seems they are ok.
?
U1 ne602 - pin 8 shows square wave 7.6vpp when keyed, so seems it is powering correct.
?
Pin 6 shows 8vpp square wave, almost identical to pin 8, THIS SEEMS VERY WRONG to me??? The manual says it should be 1.5vpp sinewave.
Same exact thing on pin 4 and 5.? Do I have a bad NE602???
?
I check U1 pin 1 - for input.? I have 252mvpp sinewave 2.07mhz.
?
I did use a socket, so at least I can get it out easy.
? Seems to me NE602 is bad or shorted.? These chips are no longer made. Hmmm
?
I tried another NE602. same result.? Here is what I see on pin 6 u1.
?
?
7.6vpp.??
?
It seems the crstal oscillator is working but the level is too low and a scope loads it down.? This is what I see on the tinysa.
?
?
So I swapped the ne602 with a new one same result.? The current circuit draws 70ma receive and 100ma key down.??
?
I would appreciate any debugging advice.? Thanks!
?
 

开云体育

It’s been a very long time since I worked on one of these. I barely remember designing it. You have dumped a ton of stuff on me and it will take me several days to go through it all.?

Steve K1EL?

On Feb 8, 2025, at 1:24?PM, bruce williams via groups.io <n9jcv@...> wrote:

?
So I have started to build this kit I had tucked away for many years.? I have a DMM, scope (rigol), a tinysa and some other things.? Here is the state of things;
?
I have built many kits before and my soldering skills are pretty good.? I have inspected for cold or shorted contacts.? I have now just completed step 13 the PSOC.? PSOC Checkout is good.? All steps prior to 13 checked out as the manual stated, with one minor exception.? Probably just a misunderstanding on my part.??
?
Step 11 says "you will see the keyed 12 volt line turn on and off..."? i have keyer mode set to sup and when I key i see square wave (dits) but these are 7.5vpp.? I believe that is because zd1 is clamping the 12v line.? I think this part is working ok and not impacting my current situation.? Your thoughts please?
?
All the above is with the keyer SUP selected.? If I select KEY, which is actually what I want as I use a straight key, the keyed 12v does not work.? I dont know what to think about this ???
?
Now, the current issue.? Step 13 psoc complete and working.? Now is the vfo calibration.? I do not have ct3 thus did not install.? My vfo min was about 7150, so i had to add 3 windings and now it is at 7005 which is great for me as I never go that low in band anyway.? Vfo on lcd is working great, with 10k 1 turn currently installed per directions.
?
Here is a pic fro scope tp4.? I see the same keyed or not keyed, seems fine to me?
<20250208_092322.jpg>
?
I am seeing 2.05mhz at 12.5vpp.? I also ched this with tinySa and is shows 2.061mhz at -70db.? So I believe all of this confirms the vfo section is good?
?
I believe the vfo buffer is good as the vfo displays and tuning up and down works and is stable.
?
Next it says check the vfo injection to the ne602 u1.? U1 pin 1 shows 256mv 2.06mhz signal on pin 1.? So I think it is good so far?
<17390296048913114188621786647283.jpg>
?
Now next steps are to be tested key down.? So in SUP key mode, keydown.? On R4 I see 5.6v nice clean square wave.? Q3 and Q4 also show square wave diff volts.? Seems they are ok.
?
U1 ne602 - pin 8 shows square wave 7.6vpp when keyed, so seems it is powering correct.
?
Pin 6 shows 8vpp square wave, almost identical to pin 8, THIS SEEMS VERY WRONG to me??? The manual says it should be 1.5vpp sinewave.
Same exact thing on pin 4 and 5.? Do I have a bad NE602???
?
I check U1 pin 1 - for input.? I have 252mvpp sinewave 2.07mhz.
<17390318403348952177782845633402.jpg>
?
I did use a socket, so at least I can get it out easy.
? Seems to me NE602 is bad or shorted.? These chips are no longer made. Hmmm
?
I tried another NE602. same result.? Here is what I see on pin 6 u1.
?
<17390383236944523056792518546175.jpg>
?
7.6vpp.??
?
It seems the crstal oscillator is working but the level is too low and a scope loads it down.? This is what I see on the tinysa.
?
<20250208_121807.jpg>
?
So I swapped the ne602 with a new one same result.? The current circuit draws 70ma receive and 100ma key down.??
?
I would appreciate any debugging advice.? Thanks!
?
 

No problem.? I just tried to be thourough.? I am not an EE and my skills are not great.? I am learning as I go.? Thanks!
 

Trying an active rf probe. It shows low voltage


On Sat, Feb 8, 2025, 11:12 AM bruce williams via <n9jcv=[email protected]> wrote:
No problem.? I just tried to be thourough.? I am not an EE and my skills are not great.? I am learning as I go.? Thanks!
 

That is something I dont have unfortunately.??
 

开云体育

An RF probe is definitely not needed, a general coverage receiver works much better.
Steve K1EL?

On Feb 8, 2025, at 9:17?PM, bruce williams via groups.io <n9jcv@...> wrote:

?
That is something I dont have unfortunately.??
 

To all;
?
I have been able to find and fix all my problems with the VFO and TX Mixer stage with some help from another ham.??
?
I was trying to verify the TX mixer was working, but I had not yet at that time calibrated the displayed frequency on the LCD.? I also was using a straight key in SUP key mode to get a series of dits, as my straight key in KEY mode did not work.? So there were a few issues at play here.? My VFO was running and the LCD did display a frequency 7005-7085, but that is not where it really was.? So I calculated the frequency it should have been at based on the VFO actual and add 4195.2.? This then led me to discover my LCD was reading approximately 50Khz high.? So I did the calibration and lowered.? Doing this I used a tinysa and a Sony receiver to verify where the vfo signal was.? Then I had to adjust some turns on the L5 in the vfo, but eventually I got to a vfo and LCD displayed frequency of 7010 to 7091, which is fine for my needs.? I verified this again and all so far is well.
?
The next issue I had was the checkout of the TX Mixer stage.? Doing this with a series of dits, was impossible, at least for my skills and modest Rigol scope.? I would have had to be able to see a AC 4.9152 and 7mhz signal riding on a DC voltage of 7.5 volts, in a 55ms pulse(dit).? So this ham who helped me, told me my Key was not wired correctly.? He was right.? I have many other QRP rigs, Norcal, QMX, HB, TAC1, they all use the tip and ring to key.? This radio however requires the Sleeve and Ring for a straight key.? So I wired as such and changed the key mode to KEY and then had a working straight key.? Now that I could key down and hold it, I could use my scope to see the sinewaves.? From there I did the required tuning in the TX Mixer stage and everything is well there.? No I can continue with the build.? I hope this helps someone, and I would be glad to assist anyone who might have a similar issue.
Thanks to all
Bruce

1 - 7 of 7