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K1 transceiver kit won't transmit

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Foreman

K1 transceiver kit won't transmit

My son and I have been building a 20m & 15m K1 over the past year. Great kit! It is assembled and we are trying to finish aligning the radio. however, it will not transmit. We have tried signal tracing it and cannot get a reading on any of the test points. Receiver works fine. We did extensive multimeter testing and found that IC U8, SA602AN, was out of tolerance. We replaced it but the transmitter is still inop. A very kind Elmer will assist us with test equipment but wanted to gather opinions from the reflector participants on how to proceed. Just to bring all the information together here in one place, the great folks at Elecraft shared the following recommendations:

Filter Board RF voltages using a scope at these filter board connector pins:

P1-4 Premix oscillator signal 200-500mVpp
P1-6 Premix signal output signal 200-500mVpp (must be peaked with the bandpass trimmers)
P2-1 TX Buffer output 1-3Vpp
P2-8 Filter board TX output to Driver 1-3Vpp
P3-1 PA output up to 40-55Vpp
P3-8 Output from lowpass filter 40-55Vpp

Vpp = RF volts peak to peak.
mVpp = RF millivolts peak to peak.

An RF probe will show the rms RF voltage levels, or about 35% of these pk-pk values. Appendix E, or any ARRL Handbook shows how to build an RF probe. We also sell an RF probe kit for $10. Use an oscilloscope if you can get access to one.

Test the rig on all bands too. The filter board is difficult to align the first time, so be patient when aligning it, and try to peak it on signals in receive, or in transmit with an RF probe or scope at the indicated places shown above.

Thanks.

Martin, KL3ID
Micah, KL3IE
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Don Wilhelm-4

Re: K1 transceiver kit won't transmit

Martin and Micah,

The information Gary gave you is exactly correct.
I would add three additional comments:
1) The oscilloscope should have a 10X probe for reliable readings
(otherwise use an RF Probe)
2) If you have a 4 band board, start with the trimmer slots parallel
with the long edge of the board - the final settings will not be more
than 20 degrees from that position. You must align 15 meters (or 17
meters) before 20 meters, and 30 meters before 40 meters (the band order
is not important for the 2 band board)
3) After peaking the Pre-Mixer bandpass at P1 pin 6, go on to peak the
TX Buffer output, and then with the probe still on the TX Buffer output,
go back and touch up the Pre-Mix again - the 'scope probe may load the
premix filter output a bit and must be tweaked again without the probe
on P1 pin 6.

Observe the sequence of alignment, it must be done in order. Let us
know where the expected RF voltages cannot be reached.

73,
Don W3FPR

On 3/4/2013 1:49 AM, Foreman wrote:

> My son and I have been building a 20m & 15m K1 over the past year. Great kit! It is assembled and we are trying to finish aligning the radio. however, it will not transmit. We have tried signal tracing it and cannot get a reading on any of the test points. Receiver works fine. We did extensive multimeter testing and found that IC U8, SA602AN, was out of tolerance. We replaced it but the transmitter is still inop. A very kind Elmer will assist us with test equipment but wanted to gather opinions from the reflector participants on how to proceed. Just to bring all the information together here in one place, the great folks at Elecraft shared the following recommendations:
>
> Filter Board RF voltages using a scope at these filter board connector pins:
>
> P1-4 Premix oscillator signal 200-500mVpp
> P1-6 Premix signal output signal 200-500mVpp (must be peaked with the bandpass trimmers)
> P2-1 TX Buffer output 1-3Vpp
> P2-8 Filter board TX output to Driver 1-3Vpp
> P3-1 PA output up to 40-55Vpp
> P3-8 Output from lowpass filter 40-55Vpp
>
> Vpp = RF volts peak to peak.
> mVpp = RF millivolts peak to peak.
>
> An RF probe will show the rms RF voltage levels, or about 35% of these pk-pk values. Appendix E, or any ARRL Handbook shows how to build an RF probe. We also sell an RF probe kit for $10. Use an oscilloscope if you can get access to one.
>
> Test the rig on all bands too. The filter board is difficult to align the first time, so be patient when aligning it, and try to peak it on signals in receive, or in transmit with an RF probe or scope at the indicated places shown above.
>
> Thanks.
>
> Martin, KL3ID
> Micah, KL3IE
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

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Mike Morrow-3

Re: K1 transceiver kit won't transmit

In reply to this post by Foreman

It helps to know **exactly** where in the manual the problem is detected.
It appears that you are building a two-band filter board, which is also
important information.

I assume that you are using K1 manual Rev. I, that **all** the testing on
page 46 (especially the late step on that page) was completed without
anomaly, and that the problem appeared at the step in the first column
on page 47 that states:

"Put the K1 into TUNE mode. Using the alignment tool, adjust
L1, L2, L5 and L6 for maximum output. If the output jumps up to
well above 2 watts, exit TUNE mode, then re-enter it again."

(The last couple of K1 manual revisions corrected a problem that had
been in the manual for a decade that sometimes caused problems if
the errats sheet had not been followed.)

> ...it will not transmit.

It helps to know **exactly** what indications show the problem being
reported.

What does this mean, exactly? Does it NOT go into transmit mode at all?
Does it go into transmit mode, but displays PO.1 for all adjustments
you make to the inductors above? This could be caused simply by not having
the jumper on P3 on the RF board on the correct two pins (1 to 2), or missing.
Do you have an external wattmeter and dummy load that shows no output?
Do you have an external receiver that could detect at least the existence
of some transmitted signal?

The tuning of the two-band board is fairly broad, compared to the four-band
board. But the peaking for transmit will still be rather sharp, compared to
what was required for receive. It is easy to tune past the transmit peaks
and wind up with P0.1 shown in the display.

For the two band board (in contrast to the four-band board), it doe *NOT*
matter which band you align first. If you have no success on the one band,
try the other to see if the anomaly is only in the circuitry for one band.

>Filter Board RF voltages using a scope at these filter board connector pins:
>
>P1-4 Premix oscillator signal 200-500mVpp
>P1-6 Premix signal output signal 200-500mVpp (must be peaked with the bandpass trimmers)
>P2-1 TX Buffer output 1-3Vpp
>P2-8 Filter board TX output to Driver 1-3Vpp
>P3-1 PA output up to 40-55Vpp
>P3-8 Output from lowpass filter 40-55Vpp

RF voltages are nice, but the start of troubleshooting should verify first
a few DC voltages. There should be 12 vdc on the RF board at the collectors
of driver Q6 and PA Q7 **even when not transmitting**. Don't measure these
when transmitting, but check them in receive mode. If there isn't 12 VDC
then, there won't be any point to checking anything else until there is.

Good luck.

Mike / KK5F

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Jim Wiley

Re: K1 transceiver kit won't transmit

In reply to this post by Don Wilhelm-4

Don -

I am Jim, KL7CC, helping Micah with his K1.

Further testing indicates the following: With PO set for 3.0 watts
(requested) we get approx 18V PP RF at the collector of Q6, and6V PP at
the base of Q7. NO volts RF at the collector of Q7, but the DC voltage
reads about 12.8 DC. Have not tried to peak all stages, but seems to me
that the problem is likely a toasted Q7. Watcha think?

- Jim, KL7CC

On 3/4/2013 4:47 AM, Don Wilhelm wrote:

> Martin and Micah,
>
> The information Gary gave you is exactly correct.
> I would add three additional comments:
> 1) The oscilloscope should have a 10X probe for reliable readings
> (otherwise use an RF Probe)
> 2) If you have a 4 band board, start with the trimmer slots parallel
> with the long edge of the board - the final settings will not be more
> than 20 degrees from that position. You must align 15 meters (or 17
> meters) before 20 meters, and 30 meters before 40 meters (the band
> order is not important for the 2 band board)
> 3) After peaking the Pre-Mixer bandpass at P1 pin 6, go on to peak the
> TX Buffer output, and then with the probe still on the TX Buffer
> output, go back and touch up the Pre-Mix again - the 'scope probe may
> load the premix filter output a bit and must be tweaked again without
> the probe on P1 pin 6.
>
> Observe the sequence of alignment, it must be done in order. Let us
> know where the expected RF voltages cannot be reached.
>
> 73,
> Don W3FPR
>
> On 3/4/2013 1:49 AM, Foreman wrote:
>> My son and I have been building a 20m & 15m K1 over the past year.
>> Great kit! It is assembled and we are trying to finish aligning the
>> radio. however, it will not transmit. We have tried signal tracing it
>> and cannot get a reading on any of the test points. Receiver works
>> fine. We did extensive multimeter testing and found that IC U8,
>> SA602AN, was out of tolerance. We replaced it but the transmitter is
>> still inop. A very kind Elmer will assist us with test equipment but
>> wanted to gather opinions from the reflector participants on how to
>> proceed. Just to bring all the information together here in one
>> place, the great folks at Elecraft shared the following recommendations:
>>
>> Filter Board RF voltages using a scope at these filter board
>> connector pins:
>>
>> P1-4 Premix oscillator signal 200-500mVpp
>> P1-6 Premix signal output signal 200-500mVpp (must be peaked with the
>> bandpass trimmers)
>> P2-1 TX Buffer output 1-3Vpp
>> P2-8 Filter board TX output to Driver 1-3Vpp
>> P3-1 PA output up to 40-55Vpp
>> P3-8 Output from lowpass filter 40-55Vpp
>>
>> Vpp = RF volts peak to peak.
>> mVpp = RF millivolts peak to peak.
>>
>> An RF probe will show the rms RF voltage levels, or about 35% of
>> these pk-pk values. Appendix E, or any ARRL Handbook shows how to
>> build an RF probe. We also sell an RF probe kit for $10. Use an
>> oscilloscope if you can get access to one.
>>
>> Test the rig on all bands too. The filter board is difficult to align
>> the first time, so be patient when aligning it, and try to peak it on
>> signals in receive, or in transmit with an RF probe or scope at the
>> indicated places shown above.
>>
>> Thanks.
>>
>> Martin, KL3ID
>> Micah, KL3IE
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

Don Wilhelm-4

Re: K1 transceiver kit won't transmit

Jim,

Either the T4 leads are in the wrong holes or Q7 is toast. Check the
lead placement of T4 against the illustration in the manual.

73,
Don W3FPR

On 3/7/2013 12:47 AM, Jim Wiley wrote:

> Don -
>
> I am Jim, KL7CC, helping Micah with his K1.
>
>
> Further testing indicates the following: With PO set for 3.0 watts
> (requested) we get approx 18V PP RF at the collector of Q6, and6V PP
> at the base of Q7. NO volts RF at the collector of Q7, but the DC
> voltage reads about 12.8 DC. Have not tried to peak all stages, but
> seems to me that the problem is likely a toasted Q7. Watcha think?
>
> - Jim, KL7CC
>
>
> On 3/4/2013 4:47 AM, Don Wilhelm wrote:
>> Martin and Micah,
>>
>> The information Gary gave you is exactly correct.
>> I would add three additional comments:
>> 1) The oscilloscope should have a 10X probe for reliable readings
>> (otherwise use an RF Probe)
>> 2) If you have a 4 band board, start with the trimmer slots parallel
>> with the long edge of the board - the final settings will not be more
>> than 20 degrees from that position. You must align 15 meters (or 17
>> meters) before 20 meters, and 30 meters before 40 meters (the band
>> order is not important for the 2 band board)
>> 3) After peaking the Pre-Mixer bandpass at P1 pin 6, go on to peak
>> the TX Buffer output, and then with the probe still on the TX Buffer
>> output, go back and touch up the Pre-Mix again - the 'scope probe may
>> load the premix filter output a bit and must be tweaked again without
>> the probe on P1 pin 6.
>>
>> Observe the sequence of alignment, it must be done in order. Let us
>> know where the expected RF voltages cannot be reached.
>>
>> 73,
>> Don W3FPR
>>
>> On 3/4/2013 1:49 AM, Foreman wrote:
>>> My son and I have been building a 20m & 15m K1 over the past year.
>>> Great kit! It is assembled and we are trying to finish aligning the
>>> radio. however, it will not transmit. We have tried signal tracing
>>> it and cannot get a reading on any of the test points. Receiver
>>> works fine. We did extensive multimeter testing and found that IC
>>> U8, SA602AN, was out of tolerance. We replaced it but the
>>> transmitter is still inop. A very kind Elmer will assist us with
>>> test equipment but wanted to gather opinions from the reflector
>>> participants on how to proceed. Just to bring all the information
>>> together here in one place, the great folks at Elecraft shared the
>>> following recommendations:
>>>
>>> Filter Board RF voltages using a scope at these filter board
>>> connector pins:
>>>
>>> P1-4 Premix oscillator signal 200-500mVpp
>>> P1-6 Premix signal output signal 200-500mVpp (must be peaked with
>>> the bandpass trimmers)
>>> P2-1 TX Buffer output 1-3Vpp
>>> P2-8 Filter board TX output to Driver 1-3Vpp
>>> P3-1 PA output up to 40-55Vpp
>>> P3-8 Output from lowpass filter 40-55Vpp
>>>
>>> Vpp = RF volts peak to peak.
>>> mVpp = RF millivolts peak to peak.
>>>
>>> An RF probe will show the rms RF voltage levels, or about 35% of
>>> these pk-pk values. Appendix E, or any ARRL Handbook shows how to
>>> build an RF probe. We also sell an RF probe kit for $10. Use an
>>> oscilloscope if you can get access to one.
>>>
>>> Test the rig on all bands too. The filter board is difficult to
>>> align the first time, so be patient when aligning it, and try to
>>> peak it on signals in receive, or in transmit with an RF probe or
>>> scope at the indicated places shown above.
>>>
>>> Thanks.
>>>
>>> Martin, KL3ID
>>> Micah, KL3IE
>>> ______________________________________________________________
>>> Elecraft mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:[hidden email]
>>>
>>> This list hosted by: http://www.qsl.net
>>> Please help support this email list: http://www.qsl.net/donate.html
>>>
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>
>