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KN-Q7A Board rev. 2.2 complete circuit diagram.


Robert Hudson
 

Hi Al


New to this group.


A member of my radio club built the above kit and was trying to get it going with the Rev C notes.  He asked me to have look and see if I could get it going.   the Rev C refers to a 4pin MIC connection and Rev D shows the 5 pin MIC connection on the board and he has purchased a speaker /MIC with the kit.   The manual says that there is a complete circuit diagram but I could not find it in the files section or the website.   This would be helpful and would appreciate a copy if anyone can help.


The manual also said that a HM Series Icon mike will work with it.    Once the 5 pin cable to the 8 pin MIC socket was wired correctly  my HM-36 worked for PTT and started to get power output and could see the modulating signal on my CRO, but only 0.5 watts.

Adjusted the bias current to 0.543 Amps and it appeared to increase the power but while holding the mic button down and no modulation the power decreased.   Have I interpreted the instructions correctly?   On my other transceivers on SSB there maybe a quick flicker of power then nothing till there is some modulation.  Also with AM I would be able to see steady output to be able to adjust the transmitter.


  I have a 2 tone battery operated board which I will wire into an 8 pin mic socket with a switch for PTT and see what Happens.   I would be good to have a complete schematic  with the manual for reference and service at a later date.


I appreciate this forum and look forward to some clues.


Bob VK2AOR


Adam Rong
 

Bob,

Please download the full manual package including schematic from:


The 5 pin connector has one additional pin for speaker output, and it should connect to pin 8 of the round mic connector on panel. For ICOM HM-36, it does not have speaker built in, but we do have supply of speaker microphone.

If your ICOM HM-36 is not electret type, the output can be too low to drive enough RF output. You need to talk loudly to your microphone to have higher RF output. If you don’t talk to the microphone, you will get nothing after the first moment of pressing PTT.

Thanks,
Adam

在 2017年7月17日,下午8:44,vk2aor@... [CHINA_QRP] <CHINA_QRP@...> 写道:


Hi Al


New to this group.


A member of my radio club built the above kit and was trying to get it going with the Rev C notes.  He asked me to have look and see if I could get it going.   the Rev C refers to a 4pin MIC connection and Rev D shows the 5 pin MIC connection on the board and he has purchased a speaker /MIC with the kit.   The manual says that there is a complete circuit diagram but I could not find it in the files section or the website.   This would be helpful and would appreciate a copy if anyone can help.


The manual also said that a HM Series Icon mike will work with it.    Once the 5 pin cable to the 8 pin MIC socket was wired correctly  my HM-36 worked for PTT and started to get power output and could see the modulating signal on my CRO, but only 0.5 watts.

Adjusted the bias current to 0.543 Amps and it appeared to increase the power but while holding the mic button down and no modulation the power decreased.   Have I interpreted the instructions correctly?   On my other transceivers on SSB there maybe a quick flicker of power then nothing till there is some modulation.  Also with AM I would be able to see steady output to be able to adjust the transmitter.


  I have a 2 tone battery operated board which I will wire into an 8 pin mic socket with a switch for PTT and see what Happens.   I would be good to have a complete schematic  with the manual for reference and service at a later date.


I appreciate this forum and look forward to some clues.


Bob VK2AOR




n7rgw
 

The difference (main) between Rev C and Rev D is the addition of a speaker mike capability.  Thus, an additional pin is added to the printed circuit board.  The speaker/mike will work with either Rev C or Rev D boards, but you would have to run a wire to the microphone connector (Pin 8) from the speaker connection.
You can download the Rev D manual and other bits of information from my website http://www.larvell.net/Side_Left_B/Download.htm.   (www.qrvtronics.com)

A couple of issues that I have found with power output are as follows.  Make sure that you have wound the toroids properly (easy to miss-count).  See: http://www.larvell.net/Side_Left_B/files/KN-Q7A_App_WindingTheToroid.pdf for additional help.  Make sure that the wire leads have been properly stripped.  With an ohmmeter, you can check the points on the printed circuit boards for the coils making contact.  

The next issue is to check the Transmit Band Pass filter for proper tuning.  If you have a signal generator and an oscilloscope, you can adjust the filter without power to your radio.  I inject the signal at pin 4 on the NE602 and check the signal with the oscilloscope on the 680 ohm resistor.  Adjust the coils for maximum amplitude.

If all that fails, Short Pin 2 and 3 on the NE602 nearest the IF crystal.  This will take the radio out of SSB and you should transmit only the carrier wave.

Check to see where you are loosing the signal.  With an oscilloscope check the amplitude on Pin 4 of the NE602.  Press and release the push-to-talk button on each test.  Next look at the amplitude on the SMD part C3357 on the tab.  The amplitude should have increased.  Next check the amplitude on the Collector of the D882 transistor.  Again, the amplitude should have increased.  Finally, check the amplitude on the 104 cap that leads into the final High Pass Filter section.  You should get a very large voltage swing.

One other thing that I will do just to check the transmit section would be to inject a small signal at the carrier frequency at the 680 ohm resistor.  Try about 50 mV to 100 mV if possible.  Then check each step of the transmitter with an oscilloscope.

You can contact me directly at n7rgw@...
Good luck
Larry


 


JOHN CRONHELM
 

The winding of the 3 smaller toroids that you describe is very different from the way it is described in the manual.  Not sure why the difference.
John, vo1jcc.


On Jul 17, 2017, at 2:31 PM, larry.lovell@... [CHINA_QRP] <CHINA_QRP@...> wrote:

 

The difference (main) between Rev C and Rev D is the addition of a speaker mike capability.  Thus, an additional pin is added to the printed circuit board.  The speaker/mike will work with either Rev C or Rev D boards, but you would have to run a wire to the microphone connector (Pin 8) from the speaker connection.

You can download the Rev D manual and other bits of information from my website http://www.larvell.net/Side_Left_B/Download.htm.   (www.qrvtronics.com)

A couple of issues that I have found with power output are as follows.  Make sure that you have wound the toroids properly (easy to miss-count).  See: http://www.larvell.net/Side_Left_B/files/KN-Q7A_App_WindingTheToroid.pdf for additional help.  Make sure that the wire leads have been properly stripped.  With an ohmmeter, you can check the points on the printed circuit boards for the coils making contact.  

The next issue is to check the Transmit Band Pass filter for proper tuning.  If you have a signal generator and an oscilloscope, you can adjust the filter without power to your radio.  I inject the signal at pin 4 on the NE602 and check the signal with the oscilloscope on the 680 ohm resistor.  Adjust the coils for maximum amplitude.

If all that fails, Short Pin 2 and 3 on the NE602 nearest the IF crystal.  This will take the radio out of SSB and you should transmit only the carrier wave.

Check to see where you are loosing the signal.  With an oscilloscope check the amplitude on Pin 4 of the NE602.  Press and release the push-to-talk button on each test.  Next look at the amplitude on the SMD part C3357 on the tab.  The amplitude should have increased.  Next check the amplitude on the Collector of the D882 transistor.  Again, the amplitude should have increased.  Finally, check the amplitude on the 104 cap that leads into the final High Pass Filter section.  You should get a very large voltage swing.

One other thing that I will do just to check the transmit section would be to inject a small signal at the carrier frequency at the 680 ohm resistor.  Try about 50 mV to 100 mV if possible.  Then check each step of the transmitter with an oscilloscope.

You can contact me directly at n7rgw@...
Good luck
Larry


 


Adam Rong
 

Larry's way is okay but not the best. Please follow the way in manual for good performance.

于 2017-7-18 7:53, John Cronhelm johncronhelm@... [CHINA_QRP] 写道:

 
The winding of the 3 smaller toroids that you describe is very different from the way it is described in the manual.  Not sure why the difference.
John, vo1jcc.


On Jul 17, 2017, at 2:31 PM, larry.lovell@... [CHINA_QRP] <CHINA_QRP@...> wrote:

 

The difference (main) between Rev C and Rev D is the addition of a speaker mike capability.  Thus, an additional pin is added to the printed circuit board.  The speaker/mike will work with either Rev C or Rev D boards, but you would have to run a wire to the microphone connector (Pin 8) from the speaker connection.

You can download the Rev D manual and other bits of information from my website http://www.larvell.net/Side_Left_B/Download.htm.   (www.qrvtronics.com)

A couple of issues that I have found with power output are as follows.  Make sure that you have wound the toroids properly (easy to miss-count).  See: http://www.larvell.net/Side_Left_B/files/KN-Q7A_App_WindingTheToroid.pdf for additional help.  Make sure that the wire leads have been properly stripped.  With an ohmmeter, you can check the points on the printed circuit boards for the coils making contact.  

The next issue is to check the Transmit Band Pass filter for proper tuning.  If you have a signal generator and an oscilloscope, you can adjust the filter without power to your radio.  I inject the signal at pin 4 on the NE602 and check the signal with the oscilloscope on the 680 ohm resistor.  Adjust the coils for maximum amplitude.

If all that fails, Short Pin 2 and 3 on the NE602 nearest the IF crystal.  This will take the radio out of SSB and you should transmit only the carrier wave.

Check to see where you are loosing the signal.  With an oscilloscope check the amplitude on Pin 4 of the NE602.  Press and release the push-to-talk button on each test.  Next look at the amplitude on the SMD part C3357 on the tab.  The amplitude should have increased.  Next check the amplitude on the Collector of the D882 transistor.  Again, the amplitude should have increased.  Finally, check the amplitude on the 104 cap that leads into the final High Pass Filter section.  You should get a very large voltage swing.

One other thing that I will do just to check the transmit section would be to inject a small signal at the carrier frequency at the 680 ohm resistor.  Try about 50 mV to 100 mV if possible.  Then check each step of the transmitter with an oscilloscope.

You can contact me directly at n7rgw@...
Good luck
Larry