KX-1 20 Meter Deafness

classic Classic list List threaded Threaded
11 messages Options
Reply | Threaded
Open this post in threaded view
|

KX-1 20 Meter Deafness

Kurt Pawlikowski
Hi,

    First, thanks for reading. Hopefully, it won't be boring for those
lucky K3 guys and gals...

    CONFIGURATION

    KX-1, 3080 upgrade. ATU currently removed and antenna jumper
installed for testing.Using XG-2 as a signal source. I have confirmed
the XG-2 seems to be working about as expected with another receiver
(about S-10 at 50uv and S-0 (but still in the speakers) at 1uv).

    SYMPTOM

    With normal operation, receive levels appear normal on 80 and 40 (I
can make contacts), but the XG2 is not peaking the KX-1's meter (I used
the XG-2 to calibrate the meter). 20 meters has always seemed deaf to
me. I don't remember how well the XG-2 was received on 20 when I
calibrated it. Here's the real "kicker": On 20 meters, with the XG-2
attached, I hear *no* volume difference between 50 and 1uv (which means
the KX-1's receiver is picking up the signal by proximity, not through
the antenna connection). If I touch the RX antenna connection almost
anywhere between the low-pass filter and the input of the Rx Mixer (U6,
pin 1), 20 meters comes way up (from nothing to receiving moderately
weak signals and noise). Touching the RX antenna line on 80 and 40
appears to have little or no affect. Output power on 20 meters does not
register full power, but I'm not sure if this is a calibration problem
as I don't have an accurate power meter. Also, when I couple a grid dip
meter into the RX, when tuned to 30 or 20 meters, I get a marked "dip"
just at about 17 MHz.

    REASONING AND TROUBLESHOOTING

    These are the things I've done and why...

    1) Tested continuity between the antenna input and CA (measures
about 0.2 ohm). If I had messed up any of the connections on the 8030
coil board, I would have expected an open. 0.2 ohms *seems* consistent.
    2) Disconnected leads A and B from the 3080 board (thought they
might have been interfering).
    3) I inspected the 8030 coil board coil winding and installation.
They appear okay.
    4) I checked that T2 is wound and installed correctly.
    5) I have checked the values of capacitors in the low-pass filter
and mixer circuits (marked values only - not measured).
    6) I've inspected the solder connections (connections seem to be
verified by continuity tests).
    7) I've made sure the relays, K1 and K2, are in the proper state
("Normal" for 30 and 20 meters - Added capacitors are disconnected).
    8) I've verified control voltages on the 8030 SMT board.
    9) I've verified the 8030 SMT connections are to the proper places
(since I've disconnected the A and B wires and "injecting" a signal into
the Rx Antenna input seems to work well, I'm assuming that wire C  is
not at fault).
    10) I made sure D7 is properly installed. I expect if it was not,
I'd get no power out at all.
    11) Scanned QTH's news group archive for KX-1 Rx problems, which had
some suggestions, but only one solution was listed. (I don't care for
their search facility)

    OTHER

    I'm sure I've missed something... probably obvious. I guess the next
step is to build an RF probe (though I expect the levels where the
problem is will be very difficult to measure) and drag down the boat
anchor Oscilloscope (which probably doesn't have the sensitivity to
trace the signal). Gives me an idea: I'll take my other radio and see if
I can trace the signal through the circuits. I expect I won't see it on
the RX ANT connection, which is telling me the same thing I think I'm
surmising above.

    Okay. Well, that's all I can think of just now. If anyone has any
suggestions or comments, please feel free to contact me on and/or off list.

    Thanks.

    Regards,

    kurtt

    Kurt Pawlikowski, AKA WB9FMC
    The Pinrod Corporation
    [hidden email]
    (773) 284-9500
    http://pinrod.com

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com
Reply | Threaded
Open this post in threaded view
|

Re: KX-1 20 Meter Deafness

Don Wilhelm-4
Kurt,

 From all you have said, I would believe that the problem is in the
KXB3080 low pass filter.
While I agree that your continuity test indicates no apparent problem
with the toroid lead tinning, check all the connections to be certain
there is a bit of solder on both sides of the board - if not, view that
connection with suspicion.

Make certain there is no contact with the green wire from L2 to the
lower connection of the red wire.  The green wire must wrap around to
the back side of the LPF board and can inadvertently contact the #4
termination of the wire for the red winding.

The best LPF testing is visual - look for any suspicious solder
connections.  Yes, you will see a 17 MHz cutoff on the LPF if you
measure it without regard to disconnecting it from the rest of the
circuit and failing to properly terminate the filter (it is not 50 ohms
at the PA transistor side, but I have not ever calculated the proper
termination).

Perhaps it is helpful if I tell you that the green winding is the only
active portion on 40, 30 and 20 meters.  The red winding is used for 80
meters and SWB band below about 6 MHz only.

Caution:  The sensitivity of the KX1 is not as great on 20 meters as it
is on 30 or 40 meters.  Bringing a finger (or antenna) close to T2 or
many of the receiver tuned circuits after the LPF  will normally result
in an increase in receiver total output, but that is actually an
increase in broadband noise - under careful measurement conditions, the
desired signal strength will not increase even though the overall noise
level does.  Spectrogram will show that is true.

73,
Don W3FPR

Kurt Pawlikowski wrote:

> Hi,
>
>    First, thanks for reading. Hopefully, it won't be boring for those
> lucky K3 guys and gals...
>
>    CONFIGURATION
>
>    KX-1, 3080 upgrade. ATU currently removed and antenna jumper
> installed for testing.Using XG-2 as a signal source. I have confirmed
> the XG-2 seems to be working about as expected with another receiver
> (about S-10 at 50uv and S-0 (but still in the speakers) at 1uv).
>
>    SYMPTOM
>
>    With normal operation, receive levels appear normal on 80 and 40 (I
> can make contacts), but the XG2 is not peaking the KX-1's meter (I used
> the XG-2 to calibrate the meter). 20 meters has always seemed deaf to
> me. I don't remember how well the XG-2 was received on 20 when I
> calibrated it. Here's the real "kicker": On 20 meters, with the XG-2
> attached, I hear *no* volume difference between 50 and 1uv (which means
> the KX-1's receiver is picking up the signal by proximity, not through
> the antenna connection). If I touch the RX antenna connection almost
> anywhere between the low-pass filter and the input of the Rx Mixer (U6,
> pin 1), 20 meters comes way up (from nothing to receiving moderately
> weak signals and noise). Touching the RX antenna line on 80 and 40
> appears to have little or no affect. Output power on 20 meters does not
> register full power, but I'm not sure if this is a calibration problem
> as I don't have an accurate power meter. Also, when I couple a grid dip
> meter into the RX, when tuned to 30 or 20 meters, I get a marked "dip"
> just at about 17 MHz.
>
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com
Reply | Threaded
Open this post in threaded view
|

Re: KX-1 20 Meter Deafness

Kurt Pawlikowski
Don,

    I'll check the LPF board closely.

    As far as whether the signal increase, I believe it does. Since,
when I touch it, signals I an hearing on my other receiver become
apparent in the KX-1 also. And, I believe the XG-2 signal is increasing
(only by ear). I say that because the increase is very noticeable: From,
"Is it there?" to "I have to turn it down." Which is quite a jump
(probably 9dB).

    Anyway, I'll look it over more closely (maybe rebuild that board)
and report back. Thanks.

    Regards,

    kurtt

    Kurt Pawlikowski, AKA WB9FMC
    The Pinrod Corporation
    [hidden email]
    (773) 284-9500
    http://pinrod.com

Don Wilhelm wrote:

> Kurt,
>
> From all you have said, I would believe that the problem is in the
> KXB3080 low pass filter.
> While I agree that your continuity test indicates no apparent problem
> with the toroid lead tinning, check all the connections to be certain
> there is a bit of solder on both sides of the board - if not, view
> that connection with suspicion.
>
> Make certain there is no contact with the green wire from L2 to the
> lower connection of the red wire.  The green wire must wrap around to
> the back side of the LPF board and can inadvertently contact the #4
> termination of the wire for the red winding.
>
> The best LPF testing is visual - look for any suspicious solder
> connections.  Yes, you will see a 17 MHz cutoff on the LPF if you
> measure it without regard to disconnecting it from the rest of the
> circuit and failing to properly terminate the filter (it is not 50
> ohms at the PA transistor side, but I have not ever calculated the
> proper termination).
>
> Perhaps it is helpful if I tell you that the green winding is the only
> active portion on 40, 30 and 20 meters.  The red winding is used for
> 80 meters and SWB band below about 6 MHz only.
>
> Caution:  The sensitivity of the KX1 is not as great on 20 meters as
> it is on 30 or 40 meters.  Bringing a finger (or antenna) close to T2
> or many of the receiver tuned circuits after the LPF  will normally
> result in an increase in receiver total output, but that is actually
> an increase in broadband noise - under careful measurement conditions,
> the desired signal strength will not increase even though the overall
> noise level does.  Spectrogram will show that is true.
>
> 73,
> Don W3FPR
>
> Kurt Pawlikowski wrote:
>> Hi,
>>
>>    First, thanks for reading. Hopefully, it won't be boring for those
>> lucky K3 guys and gals...
>>
>>    CONFIGURATION
>>
>>    KX-1, 3080 upgrade. ATU currently removed and antenna jumper
>> installed for testing.Using XG-2 as a signal source. I have confirmed
>> the XG-2 seems to be working about as expected with another receiver
>> (about S-10 at 50uv and S-0 (but still in the speakers) at 1uv).
>>
>>    SYMPTOM
>>
>>    With normal operation, receive levels appear normal on 80 and 40 (I
>> can make contacts), but the XG2 is not peaking the KX-1's meter (I used
>> the XG-2 to calibrate the meter). 20 meters has always seemed deaf to
>> me. I don't remember how well the XG-2 was received on 20 when I
>> calibrated it. Here's the real "kicker": On 20 meters, with the XG-2
>> attached, I hear *no* volume difference between 50 and 1uv (which means
>> the KX-1's receiver is picking up the signal by proximity, not through
>> the antenna connection). If I touch the RX antenna connection almost
>> anywhere between the low-pass filter and the input of the Rx Mixer (U6,
>> pin 1), 20 meters comes way up (from nothing to receiving moderately
>> weak signals and noise). Touching the RX antenna line on 80 and 40
>> appears to have little or no affect. Output power on 20 meters does not
>> register full power, but I'm not sure if this is a calibration problem
>> as I don't have an accurate power meter. Also, when I couple a grid dip
>> meter into the RX, when tuned to 30 or 20 meters, I get a marked "dip"
>> just at about 17 MHz.
>>
>
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com
Reply | Threaded
Open this post in threaded view
|

Re: KX-1 20 Meter Deafness

Kurt Pawlikowski
In reply to this post by Don Wilhelm-4
Don,

    Okay... Frustrated, but here's what I found....

    On the LPF1 board, L1, 1 and 4 were reversed and shorted together.
This means that, for all intents and purposes, L1 was a wire. Okay,
well, it's a wire anyway, but with a lot less inductance. You know what
I mean! Hi, hi... This might explain my lower power on 20. I haven't
fully checked it out yet.

    Anyway, even after fixing this error, it is still exhibiting the
same problem on 20 meters (seems to be receiving by induction instead of
through the antenna connection). Also, particularly on 20, touching the
RX ANT connection increases the gain (confirmed by spectrograph
program). Again, I seem to have continuity.

    Well, I think that's it for tonight. I can't think of anything else
to look at right now. There is obviously something else wrong...

    Regards,

    kurtt

    Kurt Pawlikowski, AKA WB9FMC
    The Pinrod Corporation
    [hidden email]
    (773) 284-9500
    http://pinrod.com

Don Wilhelm wrote:

> Kurt,
>
> From all you have said, I would believe that the problem is in the
> KXB3080 low pass filter.
> While I agree that your continuity test indicates no apparent problem
> with the toroid lead tinning, check all the connections to be certain
> there is a bit of solder on both sides of the board - if not, view
> that connection with suspicion.
>
> Make certain there is no contact with the green wire from L2 to the
> lower connection of the red wire.  The green wire must wrap around to
> the back side of the LPF board and can inadvertently contact the #4
> termination of the wire for the red winding.
>
> The best LPF testing is visual - look for any suspicious solder
> connections.  Yes, you will see a 17 MHz cutoff on the LPF if you
> measure it without regard to disconnecting it from the rest of the
> circuit and failing to properly terminate the filter (it is not 50
> ohms at the PA transistor side, but I have not ever calculated the
> proper termination).
>
> Perhaps it is helpful if I tell you that the green winding is the only
> active portion on 40, 30 and 20 meters.  The red winding is used for
> 80 meters and SWB band below about 6 MHz only.
>
> Caution:  The sensitivity of the KX1 is not as great on 20 meters as
> it is on 30 or 40 meters.  Bringing a finger (or antenna) close to T2
> or many of the receiver tuned circuits after the LPF  will normally
> result in an increase in receiver total output, but that is actually
> an increase in broadband noise - under careful measurement conditions,
> the desired signal strength will not increase even though the overall
> noise level does.  Spectrogram will show that is true.
>
> 73,
> Don W3FPR
>
> Kurt Pawlikowski wrote:
>> Hi,
>>
>>    First, thanks for reading. Hopefully, it won't be boring for those
>> lucky K3 guys and gals...
>>
>>    CONFIGURATION
>>
>>    KX-1, 3080 upgrade. ATU currently removed and antenna jumper
>> installed for testing.Using XG-2 as a signal source. I have confirmed
>> the XG-2 seems to be working about as expected with another receiver
>> (about S-10 at 50uv and S-0 (but still in the speakers) at 1uv).
>>
>>    SYMPTOM
>>
>>    With normal operation, receive levels appear normal on 80 and 40 (I
>> can make contacts), but the XG2 is not peaking the KX-1's meter (I used
>> the XG-2 to calibrate the meter). 20 meters has always seemed deaf to
>> me. I don't remember how well the XG-2 was received on 20 when I
>> calibrated it. Here's the real "kicker": On 20 meters, with the XG-2
>> attached, I hear *no* volume difference between 50 and 1uv (which means
>> the KX-1's receiver is picking up the signal by proximity, not through
>> the antenna connection). If I touch the RX antenna connection almost
>> anywhere between the low-pass filter and the input of the Rx Mixer (U6,
>> pin 1), 20 meters comes way up (from nothing to receiving moderately
>> weak signals and noise). Touching the RX antenna line on 80 and 40
>> appears to have little or no affect. Output power on 20 meters does not
>> register full power, but I'm not sure if this is a calibration problem
>> as I don't have an accurate power meter. Also, when I couple a grid dip
>> meter into the RX, when tuned to 30 or 20 meters, I get a marked "dip"
>> just at about 17 MHz.
>>
>
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com
Reply | Threaded
Open this post in threaded view
|

Re: KX-1 20 Meter Deafness

Kurt Pawlikowski
In reply to this post by Kurt Pawlikowski
Mike,

    While my pride as a builder says, "No way!" you are probably right
and I'll probably have to rebuild that board. To paraphrase a quote: "We
hates it Mr. Baggins..."

    Regards,

    kurtt

    Kurt Pawlikowski, AKA WB9FMC
    The Pinrod Corporation
    [hidden email]
    (773) 284-9500
    http://pinrod.com

Mike wrote:

> Kurt,
>
> For what it's worth, when I built my KX-1 I had very similar problems.  I wound up sending a pic of my LPF board to Don, who spotted the slightest hint of enamel insulation in one of the toroid solder joints.  I had to look at it 4 times before I could even see it.  Anyway, I wound up pretty much rebuilding that board and it was fine after that.  It's *very* finicky.
>
> --
> 73,
> Mike, KC0KBC
>
>  -------------- Original message ----------------------
> From: Kurt Pawlikowski <[hidden email]>
>  
>> Don,
>>
>>     I'll check the LPF board closely.
>>
>>     As far as whether the signal increase, I believe it does. Since,
>> when I touch it, signals I an hearing on my other receiver become
>> apparent in the KX-1 also. And, I believe the XG-2 signal is increasing
>> (only by ear). I say that because the increase is very noticeable: From,
>> "Is it there?" to "I have to turn it down." Which is quite a jump
>> (probably 9dB).
>>
>>     Anyway, I'll look it over more closely (maybe rebuild that board)
>> and report back. Thanks.
>>
>>     Regards,
>>
>>     kurtt
>>
>>     Kurt Pawlikowski, AKA WB9FMC
>>     The Pinrod Corporation
>>     [hidden email]
>>     (773) 284-9500
>>     http://pinrod.com
>>
>> Don Wilhelm wrote:
>>    
>>> Kurt,
>>>
>>> From all you have said, I would believe that the problem is in the
>>> KXB3080 low pass filter.
>>> While I agree that your continuity test indicates no apparent problem
>>> with the toroid lead tinning, check all the connections to be certain
>>> there is a bit of solder on both sides of the board - if not, view
>>> that connection with suspicion.
>>>
>>> Make certain there is no contact with the green wire from L2 to the
>>> lower connection of the red wire.  The green wire must wrap around to
>>> the back side of the LPF board and can inadvertently contact the #4
>>> termination of the wire for the red winding.
>>>
>>> The best LPF testing is visual - look for any suspicious solder
>>> connections.  Yes, you will see a 17 MHz cutoff on the LPF if you
>>> measure it without regard to disconnecting it from the rest of the
>>> circuit and failing to properly terminate the filter (it is not 50
>>> ohms at the PA transistor side, but I have not ever calculated the
>>> proper termination).
>>>
>>> Perhaps it is helpful if I tell you that the green winding is the only
>>> active portion on 40, 30 and 20 meters.  The red winding is used for
>>> 80 meters and SWB band below about 6 MHz only.
>>>
>>> Caution:  The sensitivity of the KX1 is not as great on 20 meters as
>>> it is on 30 or 40 meters.  Bringing a finger (or antenna) close to T2
>>> or many of the receiver tuned circuits after the LPF  will normally
>>> result in an increase in receiver total output, but that is actually
>>> an increase in broadband noise - under careful measurement conditions,
>>> the desired signal strength will not increase even though the overall
>>> noise level does.  Spectrogram will show that is true.
>>>
>>> 73,
>>> Don W3FPR
>>>
>>> Kurt Pawlikowski wrote:
>>>      
>>>> Hi,
>>>>
>>>>    First, thanks for reading. Hopefully, it won't be boring for those
>>>> lucky K3 guys and gals...
>>>>
>>>>    CONFIGURATION
>>>>
>>>>    KX-1, 3080 upgrade. ATU currently removed and antenna jumper
>>>> installed for testing.Using XG-2 as a signal source. I have confirmed
>>>> the XG-2 seems to be working about as expected with another receiver
>>>> (about S-10 at 50uv and S-0 (but still in the speakers) at 1uv).
>>>>
>>>>    SYMPTOM
>>>>
>>>>    With normal operation, receive levels appear normal on 80 and 40 (I
>>>> can make contacts), but the XG2 is not peaking the KX-1's meter (I used
>>>> the XG-2 to calibrate the meter). 20 meters has always seemed deaf to
>>>> me. I don't remember how well the XG-2 was received on 20 when I
>>>> calibrated it. Here's the real "kicker": On 20 meters, with the XG-2
>>>> attached, I hear *no* volume difference between 50 and 1uv (which means
>>>> the KX-1's receiver is picking up the signal by proximity, not through
>>>> the antenna connection). If I touch the RX antenna connection almost
>>>> anywhere between the low-pass filter and the input of the Rx Mixer (U6,
>>>> pin 1), 20 meters comes way up (from nothing to receiving moderately
>>>> weak signals and noise). Touching the RX antenna line on 80 and 40
>>>> appears to have little or no affect. Output power on 20 meters does not
>>>> register full power, but I'm not sure if this is a calibration problem
>>>> as I don't have an accurate power meter. Also, when I couple a grid dip
>>>> meter into the RX, when tuned to 30 or 20 meters, I get a marked "dip"
>>>> just at about 17 MHz.
>>>>
>>>>        
>> _______________________________________________
>> Elecraft mailing list
>> Post to: [hidden email]
>> You must be a subscriber to post to the list.
>> Subscriber Info (Addr. Change, sub, unsub etc.):
>>  http://mailman.qth.net/mailman/listinfo/elecraft   
>>
>> Help: http://mailman.qth.net/subscribers.htm
>> Elecraft web page: http://www.elecraft.com
>>    
>
>
>  
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com
Reply | Threaded
Open this post in threaded view
|

Re: KX-1 20 Meter Deafness

Kurt Pawlikowski
In reply to this post by Don Wilhelm-4
Don,

    Still frustrated...

    I removed the LPF board and removed both L1 and L2. I then "hard
wired" them in, just the way they would be with the board and the relay
"off." This had no affect on the symptoms: The XG-2 signal still seems
to be being coupled direct to the board (1 uv 50 uv switch does not
change tone volume). The next step is to drag down my boat anchor
oscilloscope and take some measurements. I expect the signal level
before T2 to be too small for my old equipment to see (I don't think
it'll do micro volts - I'll have to check though.). Anyway, with the
XG-2 on 20 meters, what signal strength (p-p) should I be seeing at
different points of the circuit? I'm thinking of several points between
the antenna up to the mixer with both the 50 and 1 uv output (I may have
a hard time measuring the 50 uv level, much less the 1!). Any other
ideas are welcome...

    Regards,

    kurtt

    Kurt Pawlikowski, AKA WB9FMC
    The Pinrod Corporation
    [hidden email]
    (773) 284-9500
    http://pinrod.com

Don Wilhelm wrote:

> Kurt,
>
> From all you have said, I would believe that the problem is in the
> KXB3080 low pass filter.
> While I agree that your continuity test indicates no apparent problem
> with the toroid lead tinning, check all the connections to be certain
> there is a bit of solder on both sides of the board - if not, view
> that connection with suspicion.
>
> Make certain there is no contact with the green wire from L2 to the
> lower connection of the red wire.  The green wire must wrap around to
> the back side of the LPF board and can inadvertently contact the #4
> termination of the wire for the red winding.
>
> The best LPF testing is visual - look for any suspicious solder
> connections.  Yes, you will see a 17 MHz cutoff on the LPF if you
> measure it without regard to disconnecting it from the rest of the
> circuit and failing to properly terminate the filter (it is not 50
> ohms at the PA transistor side, but I have not ever calculated the
> proper termination).
>
> Perhaps it is helpful if I tell you that the green winding is the only
> active portion on 40, 30 and 20 meters.  The red winding is used for
> 80 meters and SWB band below about 6 MHz only.
>
> Caution:  The sensitivity of the KX1 is not as great on 20 meters as
> it is on 30 or 40 meters.  Bringing a finger (or antenna) close to T2
> or many of the receiver tuned circuits after the LPF  will normally
> result in an increase in receiver total output, but that is actually
> an increase in broadband noise - under careful measurement conditions,
> the desired signal strength will not increase even though the overall
> noise level does.  Spectrogram will show that is true.
>
> 73,
> Don W3FPR
>
> Kurt Pawlikowski wrote:
>> Hi,
>>
>>    First, thanks for reading. Hopefully, it won't be boring for those
>> lucky K3 guys and gals...
>>
>>    CONFIGURATION
>>
>>    KX-1, 3080 upgrade. ATU currently removed and antenna jumper
>> installed for testing.Using XG-2 as a signal source. I have confirmed
>> the XG-2 seems to be working about as expected with another receiver
>> (about S-10 at 50uv and S-0 (but still in the speakers) at 1uv).
>>
>>    SYMPTOM
>>
>>    With normal operation, receive levels appear normal on 80 and 40 (I
>> can make contacts), but the XG2 is not peaking the KX-1's meter (I used
>> the XG-2 to calibrate the meter). 20 meters has always seemed deaf to
>> me. I don't remember how well the XG-2 was received on 20 when I
>> calibrated it. Here's the real "kicker": On 20 meters, with the XG-2
>> attached, I hear *no* volume difference between 50 and 1uv (which means
>> the KX-1's receiver is picking up the signal by proximity, not through
>> the antenna connection). If I touch the RX antenna connection almost
>> anywhere between the low-pass filter and the input of the Rx Mixer (U6,
>> pin 1), 20 meters comes way up (from nothing to receiving moderately
>> weak signals and noise). Touching the RX antenna line on 80 and 40
>> appears to have little or no affect. Output power on 20 meters does not
>> register full power, but I'm not sure if this is a calibration problem
>> as I don't have an accurate power meter. Also, when I couple a grid dip
>> meter into the RX, when tuned to 30 or 20 meters, I get a marked "dip"
>> just at about 17 MHz.
>>
>
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com
Reply | Threaded
Open this post in threaded view
|

Re: KX-1 20 Meter Deafness

Kurt Pawlikowski
Don,

    Thanks for the tips. Here are some comments...

    XG-1: Well, when I hook it up to my vintage Yaesu 757, besides
showing signal strength difference (S-0 and S-9 respectively), the tone
audio volume is very noticeable. Also, on 40 and 80 with the KX-1, I can
hear a marked difference between the two settings. When I say that there
is no difference, there isn't even a "switch-click" between the two
settings. Very, very weird. Also, the relative position of the XG-1 to
the KX-1 seems to have no affect (which, if the signal was somehow being
directly coupled, bypassing the antenna lead, I would expect). Also, I
expect that the signal at 50 uv should be blasting in. It only sounds
like a moderate level at this time.

    Touching pre-mixer: I did notice that once my "crossed" wires on the
LFP board were fixed, I could get a "noise only" increase on at least
one other band (don't remember which) when touching the area, but on 20,
it was a true signal volume increase (confirmed with the PC's band scope
on the audio).

    I'll dig up the old yellow core toroids and put them in for now.

    Pre-3080: Since everything was built at the same time, its existence
as a "straight" KX-1 was a very short time and some months ago. I can't
remember most of yesterday, so who knows? {'-)

    It may come down to actually measuring components or finding someone
willing to take a look at it for me (maybe who already has the proper
test equipment or has a known good KX-1 for a side-by-side comparison?).
Anyway, it's all I can do for right now. Thanks again for your help.

    Regards,

    kurtt

    Kurt Pawlikowski, AKA WB9FMC
    The Pinrod Corporation
    [hidden email]
    (773) 284-9500
    http://pinrod.com

Don Wilhelm wrote:

> Kurtt,
>
> Forget the 'scope, the levels from the XG2 are too small to drive a
> 'scope.  The levels will be even less than the output of the signal
> generator.
> Do you have a crystal around that is somewhere in the 40 meter or 20
> meter band?  Plus a few parts in your junkbox?  If so, you can build
> up the crystal oscillator that is shown in the Troubleshooting section
> of the K2 manual (download the manual from Elecraft website).  And if
> the oscilloscope is old, you probably do not have a 10X probe for it,
> so also build the RF Probe.
> At this point, I don't know what else to tell you - you will need some
> basic test equipment to go much further.  You can do some more visual
> investigation.
>
> Make certain the PC Trace cut is really cut.  Be certain the added
> wire is correct and that there is no contact of that wire with the end
> of L6 nor point 'A'.  Check and recheck the soldering of all the
> capacitors in the LPF area as well as C1.
>
> How strong is the actual signal from the XG2?  Could it actually be
> that the KX1 AGC is making the signals sound about equal?  The fact
> that they sound the same may not be a problem at all.
>
> You will be better off putting the yellow core L1 and L2 in place for
> the time being.
> One thing that you can check with the 'scope is the Local Oscillator
> injection to the mixer.  You must have at least 200 mV peak to peak at
> U6 pin 6 for the mixer to work correctly.
>
> Remember that touching a probe to the area of T2 will always pick up a
> lot of noise which results in an apparent increase in the signal being
> picked up, but the actual signal strength usually does not increase.
>
> Did this KX1 work well before you added the KXB3080?  If not, then you
> may have a problem somewhere other than just the front end of the
> receiver.
>
> 73,
> Don W3FPR
>
>
>
> Kurt Pawlikowski wrote:
>> Don,
>>
>>    Still frustrated...
>>
>>    I removed the LPF board and removed both L1 and L2. I then "hard
>> wired" them in, just the way they would be with the board and the
>> relay "off." This had no affect on the symptoms: The XG-2 signal
>> still seems to be being coupled direct to the board (1 uv 50 uv
>> switch does not change tone volume). The next step is to drag down my
>> boat anchor oscilloscope and take some measurements. I expect the
>> signal level before T2 to be too small for my old equipment to see (I
>> don't think it'll do micro volts - I'll have to check though.).
>> Anyway, with the XG-2 on 20 meters, what signal strength (p-p) should
>> I be seeing at different points of the circuit? I'm thinking of
>> several points between the antenna up to the mixer with both the 50
>> and 1 uv output (I may have a hard time measuring the 50 uv level,
>> much less the 1!). Any other ideas are welcome...
>>
>>    Regards,
>>
>>    kurtt
>>
>>    Kurt Pawlikowski, AKA WB9FMC
>>    The Pinrod Corporation
>>    [hidden email]
>>    (773) 284-9500
>>    http://pinrod.com
>>
>> Don Wilhelm wrote:
>>> Kurt,
>>>
>>> From all you have said, I would believe that the problem is in the
>>> KXB3080 low pass filter.
>>> While I agree that your continuity test indicates no apparent
>>> problem with the toroid lead tinning, check all the connections to
>>> be certain there is a bit of solder on both sides of the board - if
>>> not, view that connection with suspicion.
>>>
>>> Make certain there is no contact with the green wire from L2 to the
>>> lower connection of the red wire.  The green wire must wrap around
>>> to the back side of the LPF board and can inadvertently contact the
>>> #4 termination of the wire for the red winding.
>>>
>>> The best LPF testing is visual - look for any suspicious solder
>>> connections.  Yes, you will see a 17 MHz cutoff on the LPF if you
>>> measure it without regard to disconnecting it from the rest of the
>>> circuit and failing to properly terminate the filter (it is not 50
>>> ohms at the PA transistor side, but I have not ever calculated the
>>> proper termination).
>>>
>>> Perhaps it is helpful if I tell you that the green winding is the
>>> only active portion on 40, 30 and 20 meters.  The red winding is
>>> used for 80 meters and SWB band below about 6 MHz only.
>>>
>>> Caution:  The sensitivity of the KX1 is not as great on 20 meters as
>>> it is on 30 or 40 meters.  Bringing a finger (or antenna) close to
>>> T2 or many of the receiver tuned circuits after the LPF  will
>>> normally result in an increase in receiver total output, but that is
>>> actually an increase in broadband noise - under careful measurement
>>> conditions, the desired signal strength will not increase even
>>> though the overall noise level does.  Spectrogram will show that is
>>> true.
>>>
>>> 73,
>>> Don W3FPR
>>>
>>> Kurt Pawlikowski wrote:
>>>> Hi,
>>>>
>>>>    First, thanks for reading. Hopefully, it won't be boring for those
>>>> lucky K3 guys and gals...
>>>>
>>>>    CONFIGURATION
>>>>
>>>>    KX-1, 3080 upgrade. ATU currently removed and antenna jumper
>>>> installed for testing.Using XG-2 as a signal source. I have confirmed
>>>> the XG-2 seems to be working about as expected with another receiver
>>>> (about S-10 at 50uv and S-0 (but still in the speakers) at 1uv).
>>>>
>>>>    SYMPTOM
>>>>
>>>>    With normal operation, receive levels appear normal on 80 and 40 (I
>>>> can make contacts), but the XG2 is not peaking the KX-1's meter (I
>>>> used
>>>> the XG-2 to calibrate the meter). 20 meters has always seemed deaf to
>>>> me. I don't remember how well the XG-2 was received on 20 when I
>>>> calibrated it. Here's the real "kicker": On 20 meters, with the XG-2
>>>> attached, I hear *no* volume difference between 50 and 1uv (which
>>>> means
>>>> the KX-1's receiver is picking up the signal by proximity, not through
>>>> the antenna connection). If I touch the RX antenna connection almost
>>>> anywhere between the low-pass filter and the input of the Rx Mixer
>>>> (U6,
>>>> pin 1), 20 meters comes way up (from nothing to receiving moderately
>>>> weak signals and noise). Touching the RX antenna line on 80 and 40
>>>> appears to have little or no affect. Output power on 20 meters does
>>>> not
>>>> register full power, but I'm not sure if this is a calibration problem
>>>> as I don't have an accurate power meter. Also, when I couple a grid
>>>> dip
>>>> meter into the RX, when tuned to 30 or 20 meters, I get a marked "dip"
>>>> just at about 17 MHz.
>>>>
>>>
>> ------------------------------------------------------------------------
>>
>>
>> No virus found in this incoming message.
>> Checked by AVG. Version: 8.0.100 / Virus Database: 269.23.21/1456 -
>> Release Date: 5/20/2008 6:45 AM
>>  
>
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com
Reply | Threaded
Open this post in threaded view
|

Re: KX-1 20 Meter Deafness

Kurt Pawlikowski
In reply to this post by Don Wilhelm-4
Don, Et Al,

    Looks like the unit may have had a static discharge through the
antenna. Q7, part of the receiver mute circuit was blown. I'll order one
tomorrow and go from there. Once I removed this component, 20 meters
seems to be up there where it should be. Nothing else seems to be
receiving correctly right now, but I'll attribute that to either this
(now missing) part or some issue I accidentally introduced while
troubleshooting. We'll see!

    Regards,

    kurtt

    Kurt Pawlikowski, AKA WB9FMC
    The Pinrod Corporation
    [hidden email]
    (773) 284-9500
    http://pinrod.com

Don Wilhelm wrote:

> Kurt,
>
> From all you have said, I would believe that the problem is in the
> KXB3080 low pass filter.
> While I agree that your continuity test indicates no apparent problem
> with the toroid lead tinning, check all the connections to be certain
> there is a bit of solder on both sides of the board - if not, view
> that connection with suspicion.
>
> Make certain there is no contact with the green wire from L2 to the
> lower connection of the red wire.  The green wire must wrap around to
> the back side of the LPF board and can inadvertently contact the #4
> termination of the wire for the red winding.
>
> The best LPF testing is visual - look for any suspicious solder
> connections.  Yes, you will see a 17 MHz cutoff on the LPF if you
> measure it without regard to disconnecting it from the rest of the
> circuit and failing to properly terminate the filter (it is not 50
> ohms at the PA transistor side, but I have not ever calculated the
> proper termination).
>
> Perhaps it is helpful if I tell you that the green winding is the only
> active portion on 40, 30 and 20 meters.  The red winding is used for
> 80 meters and SWB band below about 6 MHz only.
>
> Caution:  The sensitivity of the KX1 is not as great on 20 meters as
> it is on 30 or 40 meters.  Bringing a finger (or antenna) close to T2
> or many of the receiver tuned circuits after the LPF  will normally
> result in an increase in receiver total output, but that is actually
> an increase in broadband noise - under careful measurement conditions,
> the desired signal strength will not increase even though the overall
> noise level does.  Spectrogram will show that is true.
>
> 73,
> Don W3FPR
>
> Kurt Pawlikowski wrote:
>> Hi,
>>
>>    First, thanks for reading. Hopefully, it won't be boring for those
>> lucky K3 guys and gals...
>>
>>    CONFIGURATION
>>
>>    KX-1, 3080 upgrade. ATU currently removed and antenna jumper
>> installed for testing.Using XG-2 as a signal source. I have confirmed
>> the XG-2 seems to be working about as expected with another receiver
>> (about S-10 at 50uv and S-0 (but still in the speakers) at 1uv).
>>
>>    SYMPTOM
>>
>>    With normal operation, receive levels appear normal on 80 and 40 (I
>> can make contacts), but the XG2 is not peaking the KX-1's meter (I used
>> the XG-2 to calibrate the meter). 20 meters has always seemed deaf to
>> me. I don't remember how well the XG-2 was received on 20 when I
>> calibrated it. Here's the real "kicker": On 20 meters, with the XG-2
>> attached, I hear *no* volume difference between 50 and 1uv (which means
>> the KX-1's receiver is picking up the signal by proximity, not through
>> the antenna connection). If I touch the RX antenna connection almost
>> anywhere between the low-pass filter and the input of the Rx Mixer (U6,
>> pin 1), 20 meters comes way up (from nothing to receiving moderately
>> weak signals and noise). Touching the RX antenna line on 80 and 40
>> appears to have little or no affect. Output power on 20 meters does not
>> register full power, but I'm not sure if this is a calibration problem
>> as I don't have an accurate power meter. Also, when I couple a grid dip
>> meter into the RX, when tuned to 30 or 20 meters, I get a marked "dip"
>> just at about 17 MHz.
>>
>
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com
Reply | Threaded
Open this post in threaded view
|

Re: KX-1 20 Meter Deafness

Don Wilhelm-4
Kurtt,

The KX1 should receive just fine with Q7 removed.  Any other receiver
troubles are a different problem.

73,
Don W3FPR

Kurt Pawlikowski wrote:

> Don, Et Al,
>
>    Looks like the unit may have had a static discharge through the
> antenna. Q7, part of the receiver mute circuit was blown. I'll order
> one tomorrow and go from there. Once I removed this component, 20
> meters seems to be up there where it should be. Nothing else seems to
> be receiving correctly right now, but I'll attribute that to either
> this (now missing) part or some issue I accidentally introduced while
> troubleshooting. We'll see!
>
>    Regards,
>
>    kurtt
>
>    Kurt Pawlikowski, AKA WB9FMC
>    The Pinrod Corporation
>    [hidden email]
>    (773) 284-9500
>    http://pinrod.com
>
> Don Wilhelm wrote:
>> Kurt,
>>
>> From all you have said, I would believe that the problem is in the
>> KXB3080 low pass filter.
>> While I agree that your continuity test indicates no apparent problem
>> with the toroid lead tinning, check all the connections to be certain
>> there is a bit of solder on both sides of the board - if not, view
>> that connection with suspicion.
>>
>> Make certain there is no contact with the green wire from L2 to the
>> lower connection of the red wire.  The green wire must wrap around to
>> the back side of the LPF board and can inadvertently contact the #4
>> termination of the wire for the red winding.
>>
>> The best LPF testing is visual - look for any suspicious solder
>> connections.  Yes, you will see a 17 MHz cutoff on the LPF if you
>> measure it without regard to disconnecting it from the rest of the
>> circuit and failing to properly terminate the filter (it is not 50
>> ohms at the PA transistor side, but I have not ever calculated the
>> proper termination).
>>
>> Perhaps it is helpful if I tell you that the green winding is the
>> only active portion on 40, 30 and 20 meters.  The red winding is used
>> for 80 meters and SWB band below about 6 MHz only.
>>
>> Caution:  The sensitivity of the KX1 is not as great on 20 meters as
>> it is on 30 or 40 meters.  Bringing a finger (or antenna) close to T2
>> or many of the receiver tuned circuits after the LPF  will normally
>> result in an increase in receiver total output, but that is actually
>> an increase in broadband noise - under careful measurement
>> conditions, the desired signal strength will not increase even though
>> the overall noise level does.  Spectrogram will show that is true.
>>
>> 73,
>> Don W3FPR
>>
>> Kurt Pawlikowski wrote:
>>> Hi,
>>>
>>>    First, thanks for reading. Hopefully, it won't be boring for those
>>> lucky K3 guys and gals...
>>>
>>>    CONFIGURATION
>>>
>>>    KX-1, 3080 upgrade. ATU currently removed and antenna jumper
>>> installed for testing.Using XG-2 as a signal source. I have confirmed
>>> the XG-2 seems to be working about as expected with another receiver
>>> (about S-10 at 50uv and S-0 (but still in the speakers) at 1uv).
>>>
>>>    SYMPTOM
>>>
>>>    With normal operation, receive levels appear normal on 80 and 40 (I
>>> can make contacts), but the XG2 is not peaking the KX-1's meter (I used
>>> the XG-2 to calibrate the meter). 20 meters has always seemed deaf to
>>> me. I don't remember how well the XG-2 was received on 20 when I
>>> calibrated it. Here's the real "kicker": On 20 meters, with the XG-2
>>> attached, I hear *no* volume difference between 50 and 1uv (which means
>>> the KX-1's receiver is picking up the signal by proximity, not through
>>> the antenna connection). If I touch the RX antenna connection almost
>>> anywhere between the low-pass filter and the input of the Rx Mixer (U6,
>>> pin 1), 20 meters comes way up (from nothing to receiving moderately
>>> weak signals and noise). Touching the RX antenna line on 80 and 40
>>> appears to have little or no affect. Output power on 20 meters does not
>>> register full power, but I'm not sure if this is a calibration problem
>>> as I don't have an accurate power meter. Also, when I couple a grid dip
>>> meter into the RX, when tuned to 30 or 20 meters, I get a marked "dip"
>>> just at about 17 MHz.
>>>
>>
> ------------------------------------------------------------------------
>
>
> No virus found in this incoming message.
> Checked by AVG.
> Version: 8.0.100 / Virus Database: 269.23.21/1458 - Release Date: 5/21/2008 7:21 AM
>  
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com
Reply | Threaded
Open this post in threaded view
|

Re: KX-1 20 Meter Deafness

Kurt Pawlikowski
Don,

    I suspected that. At any rate, I've either blown something else
(seems 40 "almost" worked before I started troubleshooting!) or more
than that one component was damaged. Gonna have to maybe mess with the
LXB3030 with it's SMT stuff. I'm thinking that if that's damaged, its
the most expensive single part of the 3080 kit! Of course, the more I
think about it, the more it seems it'll be at least part of the
remaining issues...

    Regards,

    kurtt

    Kurt Pawlikowski, AKA WB9FMC
    The Pinrod Corporation
    [hidden email]
    (773) 284-9500
    http://pinrod.com

Don Wilhelm wrote:

> Kurtt,
>
> The KX1 should receive just fine with Q7 removed.  Any other receiver
> troubles are a different problem.
>
> 73,
> Don W3FPR
>
> Kurt Pawlikowski wrote:
>> Don, Et Al,
>>
>>    Looks like the unit may have had a static discharge through the
>> antenna. Q7, part of the receiver mute circuit was blown. I'll order
>> one tomorrow and go from there. Once I removed this component, 20
>> meters seems to be up there where it should be. Nothing else seems to
>> be receiving correctly right now, but I'll attribute that to either
>> this (now missing) part or some issue I accidentally introduced while
>> troubleshooting. We'll see!
>>
>>    Regards,
>>
>>    kurtt
>>
>>    Kurt Pawlikowski, AKA WB9FMC
>>    The Pinrod Corporation
>>    [hidden email]
>>    (773) 284-9500
>>    http://pinrod.com
>>
>> Don Wilhelm wrote:
>>> Kurt,
>>>
>>> From all you have said, I would believe that the problem is in the
>>> KXB3080 low pass filter.
>>> While I agree that your continuity test indicates no apparent
>>> problem with the toroid lead tinning, check all the connections to
>>> be certain there is a bit of solder on both sides of the board - if
>>> not, view that connection with suspicion.
>>>
>>> Make certain there is no contact with the green wire from L2 to the
>>> lower connection of the red wire.  The green wire must wrap around
>>> to the back side of the LPF board and can inadvertently contact the
>>> #4 termination of the wire for the red winding.
>>>
>>> The best LPF testing is visual - look for any suspicious solder
>>> connections.  Yes, you will see a 17 MHz cutoff on the LPF if you
>>> measure it without regard to disconnecting it from the rest of the
>>> circuit and failing to properly terminate the filter (it is not 50
>>> ohms at the PA transistor side, but I have not ever calculated the
>>> proper termination).
>>>
>>> Perhaps it is helpful if I tell you that the green winding is the
>>> only active portion on 40, 30 and 20 meters.  The red winding is
>>> used for 80 meters and SWB band below about 6 MHz only.
>>>
>>> Caution:  The sensitivity of the KX1 is not as great on 20 meters as
>>> it is on 30 or 40 meters.  Bringing a finger (or antenna) close to
>>> T2 or many of the receiver tuned circuits after the LPF  will
>>> normally result in an increase in receiver total output, but that is
>>> actually an increase in broadband noise - under careful measurement
>>> conditions, the desired signal strength will not increase even
>>> though the overall noise level does.  Spectrogram will show that is
>>> true.
>>>
>>> 73,
>>> Don W3FPR
>>>
>>> Kurt Pawlikowski wrote:
>>>> Hi,
>>>>
>>>>    First, thanks for reading. Hopefully, it won't be boring for those
>>>> lucky K3 guys and gals...
>>>>
>>>>    CONFIGURATION
>>>>
>>>>    KX-1, 3080 upgrade. ATU currently removed and antenna jumper
>>>> installed for testing.Using XG-2 as a signal source. I have confirmed
>>>> the XG-2 seems to be working about as expected with another receiver
>>>> (about S-10 at 50uv and S-0 (but still in the speakers) at 1uv).
>>>>
>>>>    SYMPTOM
>>>>
>>>>    With normal operation, receive levels appear normal on 80 and 40 (I
>>>> can make contacts), but the XG2 is not peaking the KX-1's meter (I
>>>> used
>>>> the XG-2 to calibrate the meter). 20 meters has always seemed deaf to
>>>> me. I don't remember how well the XG-2 was received on 20 when I
>>>> calibrated it. Here's the real "kicker": On 20 meters, with the XG-2
>>>> attached, I hear *no* volume difference between 50 and 1uv (which
>>>> means
>>>> the KX-1's receiver is picking up the signal by proximity, not through
>>>> the antenna connection). If I touch the RX antenna connection almost
>>>> anywhere between the low-pass filter and the input of the Rx Mixer
>>>> (U6,
>>>> pin 1), 20 meters comes way up (from nothing to receiving moderately
>>>> weak signals and noise). Touching the RX antenna line on 80 and 40
>>>> appears to have little or no affect. Output power on 20 meters does
>>>> not
>>>> register full power, but I'm not sure if this is a calibration problem
>>>> as I don't have an accurate power meter. Also, when I couple a grid
>>>> dip
>>>> meter into the RX, when tuned to 30 or 20 meters, I get a marked "dip"
>>>> just at about 17 MHz.
>>>>
>>>
>> ------------------------------------------------------------------------
>>
>>
>> No virus found in this incoming message.
>> Checked by AVG. Version: 8.0.100 / Virus Database: 269.23.21/1458 -
>> Release Date: 5/21/2008 7:21 AM
>>  
>
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com
Reply | Threaded
Open this post in threaded view
|

Re: KX-1 20 Meter Deafness

Don Wilhelm-4
Kurtt,

If you suspect the KXB3080 board strongly enough, disconnect one end of
the A, B and C wires to that board and it will be removed from the front
end circuits.  It is easy to remove the A and B wires from the KXB3080
board (solder them back on the top of the board).  The C wire is the
hardest to remove - but if you have a de-soldering gun, you can suck the
solder from both ends of the wire and pull it straight out - to replace,
just put a long wire through both holes, solder and clip the ends.

Do not remove T2 and the board capacitors added with the KXB3080 - those
should tune to 20 and 40 with the KXB3080 removed, but you will have to
re-peak the trimmers to compensate for the stray capacitance on the
KXB3080 board and the wires.

73,
Don W3FPR

Kurt Pawlikowski wrote:

> Don,
>
>    I suspected that. At any rate, I've either blown something else
> (seems 40 "almost" worked before I started troubleshooting!) or more
> than that one component was damaged. Gonna have to maybe mess with the
> LXB3030 with it's SMT stuff. I'm thinking that if that's damaged, its
> the most expensive single part of the 3080 kit! Of course, the more I
> think about it, the more it seems it'll be at least part of the
> remaining issues...
>
>    Regards,
>
>    kurtt
>
>    Kurt Pawlikowski, AKA WB9FMC
>    The Pinrod Corporation
>    [hidden email]
>    (773) 284-9500
>    http://pinrod.com
>
> Don Wilhelm wrote:
>> Kurtt,
>>
>> The KX1 should receive just fine with Q7 removed.  Any other receiver
>> troubles are a different problem.
>>
>> 73,
>> Don W3FPR
>>
>> Kurt Pawlikowski wrote:
>>> Don, Et Al,
>>>
>>>    Looks like the unit may have had a static discharge through the
>>> antenna. Q7, part of the receiver mute circuit was blown. I'll order
>>> one tomorrow and go from there. Once I removed this component, 20
>>> meters seems to be up there where it should be. Nothing else seems
>>> to be receiving correctly right now, but I'll attribute that to
>>> either this (now missing) part or some issue I accidentally
>>> introduced while troubleshooting. We'll see!
>>>
>>>    Regards,
>>>
>>>    kurtt
>>>
>>>    Kurt Pawlikowski, AKA WB9FMC
>>>    The Pinrod Corporation
>>>    [hidden email]
>>>    (773) 284-9500
>>>    http://pinrod.com
>>>
>>> Don Wilhelm wrote:
>>>> Kurt,
>>>>
>>>> From all you have said, I would believe that the problem is in the
>>>> KXB3080 low pass filter.
>>>> While I agree that your continuity test indicates no apparent
>>>> problem with the toroid lead tinning, check all the connections to
>>>> be certain there is a bit of solder on both sides of the board - if
>>>> not, view that connection with suspicion.
>>>>
>>>> Make certain there is no contact with the green wire from L2 to the
>>>> lower connection of the red wire.  The green wire must wrap around
>>>> to the back side of the LPF board and can inadvertently contact the
>>>> #4 termination of the wire for the red winding.
>>>>
>>>> The best LPF testing is visual - look for any suspicious solder
>>>> connections.  Yes, you will see a 17 MHz cutoff on the LPF if you
>>>> measure it without regard to disconnecting it from the rest of the
>>>> circuit and failing to properly terminate the filter (it is not 50
>>>> ohms at the PA transistor side, but I have not ever calculated the
>>>> proper termination).
>>>>
>>>> Perhaps it is helpful if I tell you that the green winding is the
>>>> only active portion on 40, 30 and 20 meters.  The red winding is
>>>> used for 80 meters and SWB band below about 6 MHz only.
>>>>
>>>> Caution:  The sensitivity of the KX1 is not as great on 20 meters
>>>> as it is on 30 or 40 meters.  Bringing a finger (or antenna) close
>>>> to T2 or many of the receiver tuned circuits after the LPF  will
>>>> normally result in an increase in receiver total output, but that
>>>> is actually an increase in broadband noise - under careful
>>>> measurement conditions, the desired signal strength will not
>>>> increase even though the overall noise level does.  Spectrogram
>>>> will show that is true.
>>>>
>>>> 73,
>>>> Don W3FPR
>>>>
>>>> Kurt Pawlikowski wrote:
>>>>> Hi,
>>>>>
>>>>>    First, thanks for reading. Hopefully, it won't be boring for those
>>>>> lucky K3 guys and gals...
>>>>>
>>>>>    CONFIGURATION
>>>>>
>>>>>    KX-1, 3080 upgrade. ATU currently removed and antenna jumper
>>>>> installed for testing.Using XG-2 as a signal source. I have confirmed
>>>>> the XG-2 seems to be working about as expected with another receiver
>>>>> (about S-10 at 50uv and S-0 (but still in the speakers) at 1uv).
>>>>>
>>>>>    SYMPTOM
>>>>>
>>>>>    With normal operation, receive levels appear normal on 80 and
>>>>> 40 (I
>>>>> can make contacts), but the XG2 is not peaking the KX-1's meter (I
>>>>> used
>>>>> the XG-2 to calibrate the meter). 20 meters has always seemed deaf to
>>>>> me. I don't remember how well the XG-2 was received on 20 when I
>>>>> calibrated it. Here's the real "kicker": On 20 meters, with the XG-2
>>>>> attached, I hear *no* volume difference between 50 and 1uv (which
>>>>> means
>>>>> the KX-1's receiver is picking up the signal by proximity, not
>>>>> through
>>>>> the antenna connection). If I touch the RX antenna connection almost
>>>>> anywhere between the low-pass filter and the input of the Rx Mixer
>>>>> (U6,
>>>>> pin 1), 20 meters comes way up (from nothing to receiving moderately
>>>>> weak signals and noise). Touching the RX antenna line on 80 and 40
>>>>> appears to have little or no affect. Output power on 20 meters
>>>>> does not
>>>>> register full power, but I'm not sure if this is a calibration
>>>>> problem
>>>>> as I don't have an accurate power meter. Also, when I couple a
>>>>> grid dip
>>>>> meter into the RX, when tuned to 30 or 20 meters, I get a marked
>>>>> "dip"
>>>>> just at about 17 MHz.
>>>>>
>>>>
>>> ------------------------------------------------------------------------
>>>
>>>
>>>
>>> No virus found in this incoming message.
>>> Checked by AVG. Version: 8.0.100 / Virus Database: 269.23.21/1458 -
>>> Release Date: 5/21/2008 7:21 AM
>>>  
>>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft   
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
> ------------------------------------------------------------------------
>
>
> No virus found in this incoming message.
> Checked by AVG.
> Version: 8.0.100 / Virus Database: 269.23.21/1458 - Release Date: 5/21/2008 7:21 AM
>  
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com