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K2 KSB2 low output

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gt-i

K2 KSB2 low output

Hello list,
I recently tried to use my K2 on SSB. To my suprise, there was very
little output. Even with full power it only showed the first bar. I did
some SSB QSOs during the first years...
Digging deeper, I found the DSB signal showed a Vpp of ~1V, but after
the filter the SSB signal was only 20mV or so. Is this kind of loss
normal for a 7-pole filter? If not, any hints how to repair the filter?
tnx es 73
Gernot DF5RF

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Don Wilhelm

Re: K2 KSB2 low output

Gernot,

To check for filter attenuation, I suggest you do so in receive using an
audio spectrum analyzer running on your computer to view the filter
amplitude. Feed the K2 with a broadband signal generator although noise
on a portion of a band with no signals will also work.

Compare the amplitude of the noise signal using the CW filter (width
about 700 Hz is ideal) with the amplitude from the OP1 SSB filter.
The amplitude should be about the same. If they are about the same, the
filter is OK.

Check the position of the filter passband (again with the noise source
and the audio spectrum analyzer) - the filter should extend from about
300 Hz to 2300Hz if you have the older 2.1kHz width filter. If the
newer 2.4kHz width, it should extend from about 300Hz to 2600Hz.
Adjust the BFO to align the filter passband properly.

For audio spectrum analyzers, you can use SpectrumLab or download
Spectrogram from my website www.w3fpr.com.

If the filter on receive shows near the same amplitude as the CW filter,
then the filter itself is OK. Look for the problem at D14, R10, or R11
- check soldering. You should also check to be certain that the TXS
signal from U1 pin 15 is at least 5 volts during SSB transmit. If not,
replace U1.

Try setting the SSBC parameter to 3-1 and see if the response improves.

73,
Don W3FPR

On 9/11/2017 7:53 PM, [hidden email] wrote:

> Hello list,
> I recently tried to use my K2 on SSB. To my suprise, there was very
> little output. Even with full power it only showed the first bar. I did
> some SSB QSOs during the first years...
> Digging deeper, I found the DSB signal showed a Vpp of ~1V, but after
> the filter the SSB signal was only 20mV or so. Is this kind of loss
> normal for a 7-pole filter? If not, any hints how to repair the filter?
> tnx es 73
> Gernot DF5RF
>
> ______________________________________________________________
> 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
> Message delivered to [hidden email]
>

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gt-i

Re: K2 KSB2 low output

In reply to this post by gt-i

Hello again,

Thanks to Volker, DL4ZBG, he replied directly with the following link:
http://www.qrpproject.de/Media/pdf/ZusammenfassungMods.pdf
It is a nice description of many improvements that can be made for the KSB2.
However, I believe that I do have a fault in the KSB2 (Rev. D) or K2,
since I know it behaved differently years ago. For example, the ALC
shows 7 steady bars, no matter what power level I set nor how much SSB
amplitude is produced. Regardless of the power level set, the RF signal
is never stronger than 1 bar.
I will try to experiment further, and I'm open to get any hints.
Thanks!

Gernot, DF5RF

Am 12.09.2017 um 01:53 schrieb [hidden email]:

> Hello list,
> I recently tried to use my K2 on SSB. To my suprise, there was very
> little output. Even with full power it only showed the first bar. I
> did some SSB QSOs during the first years...
> Digging deeper, I found the DSB signal showed a Vpp of ~1V, but after
> the filter the SSB signal was only 20mV or so. Is this kind of loss
> normal for a 7-pole filter? If not, any hints how to repair the filter?
> tnx es 73
> Gernot DF5RF
>
> ______________________________________________________________
> 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
> Message delivered to [hidden email]
>

Don Wilhelm

Re: K2 KSB2 low output

Gernot,

I am familiar with the mods done by QRPproject. Some are "nice" but (in
particular the increased RF Gain) are not required if you are using an
electret mic element (Elecraft MH2 or Icom mic) which has plenty of
audio output.

Make certain your KSB2 has the PSK mod installed. Look at the schematic
for the recent KSB2 and compare the values of C38, R4, R7, and R9 with
what is installed on your KSB2.

Also make certain you have adjusted the carrier balance for minimum
carrier with no audio being transmitted. In SSB mode, close the DOT
paddle to put it into transmit - the DOT signal and PTT are combined in
the K2. It is best if you can monitor the carrier with an oscilloscope,
but a monitor receiver will also do well, just adjust for minimum
S-meter on the monitor receiver.

73,
Don W3FPR

On 9/12/2017 4:59 PM, [hidden email] wrote:

gt-i

Re: K2 KSB2 low output

In reply to this post by gt-i

Solved: PIC16C72A was defective.
I had the chance to get a second K2 for reference testing. The KSB2 of
that K2 works perfectly in my K2, but not vice versa. The error is
isolated to my KSB2, but now I'd need to seek for the culprit.
I noticed a strange behavior at U1.16, which drives the DAC-Converter
for PWR-Level and ALC-THR. Yes, thats the PIC. I pulled out my old
PICStart programmer, cloned the PIC of the working K2 and programmed a
PIC16F876A which I had in the box. And here we go, full output power again!

73/72 Gernot DF5RF

Am 12.09.2017 um 22:59 schrieb [hidden email]:

> Hello again,
>
> Thanks to Volker, DL4ZBG, he replied directly with the following link:
> http://www.qrpproject.de/Media/pdf/ZusammenfassungMods.pdf
> It is a nice description of many improvements that can be made for the
> KSB2.
> However, I believe that I do have a fault in the KSB2 (Rev. D) or K2,
> since I know it behaved differently years ago. For example, the ALC
> shows 7 steady bars, no matter what power level I set nor how much SSB
> amplitude is produced. Regardless of the power level set, the RF
> signal is never stronger than 1 bar.
> I will try to experiment further, and I'm open to get any hints.
> Thanks!
>
> Gernot, DF5RF
>
>
> Am 12.09.2017 um 01:53 schrieb [hidden email]:
>> Hello list,
>> I recently tried to use my K2 on SSB. To my suprise, there was very
>> little output. Even with full power it only showed the first bar. I
>> did some SSB QSOs during the first years...
>> Digging deeper, I found the DSB signal showed a Vpp of ~1V, but after
>> the filter the SSB signal was only 20mV or so. Is this kind of loss
>> normal for a 7-pole filter? If not, any hints how to repair the filter?
>> tnx es 73
>> Gernot DF5RF
>>
>> ______________________________________________________________
>> 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
>> Message delivered to [hidden email]
>>
>
> ______________________________________________________________
> 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
> Message delivered to [hidden email]
>

gt-i

K2 K60XV K1 is not switched on

In reply to this post by gt-i

Hello,
I recently decided to upgrade my K2 to 60m and ordered the K60XV.
After building and installing the module and all the mods, I could hear
signals on 60m, but very very weak. Using the XG3 showed a difference of
8 S-points compared to all other bands. I tried to isolate the problem.
I checked if the relay K1 would switch at all (removed U1 b4), ok.
Checked if capacitance changes when turning C1/C2 - looks good. Then I
installed the module without U1 installed - 60m not recognized any more.
Seems that U1 is working, basically.
Then I fooled the K2 by installing U1 without pin 11 connected (by
applying the IC-socket-sandwich trick). And ok, I could now tune 60m
properly and to the same level as 40m.
So I got stuck now. Is U1 only "half-way" working, that is it does
communicate on the AuxBus, but cannot drive K1? BTW, I also checked the
transverter setup to see if relay K2 would be driven - and yes it clicks.
Any ideas welcome!
Thanks/73
Gernot DF5RF
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Don Wilhelm

Re: K2 K60XV K1 is not switched on

Gernot,

You either have a malfunctioning U1 or you have a bad relay at K1.
Since you were able to get K1 to operate and select 60 meters, I suspect
U1 is the problem. Request a replacement from Elecraft support.

73,
Don W3FPR

On 10/6/2017 7:41 PM, [hidden email] wrote:

> Hello,
> I recently decided to upgrade my K2 to 60m and ordered the K60XV.
> After building and installing the module and all the mods, I could hear
> signals on 60m, but very very weak. Using the XG3 showed a difference of
> 8 S-points compared to all other bands. I tried to isolate the problem.
> I checked if the relay K1 would switch at all (removed U1 b4), ok.
> Checked if capacitance changes when turning C1/C2 - looks good. Then I
> installed the module without U1 installed - 60m not recognized any more.
> Seems that U1 is working, basically.
> Then I fooled the K2 by installing U1 without pin 11 connected (by
> applying the IC-socket-sandwich trick). And ok, I could now tune 60m
> properly and to the same level as 40m.

gt-i

Re: K2 K60XV K1 is not switched on

Don,
ok will do that. Thanks for help!
73 Gernot DF5RF

Am 07.10.2017 um 02:16 schrieb Don Wilhelm:

> Gernot,
>
> You either have a malfunctioning U1 or you have a bad relay at K1.
> Since you were able to get K1 to operate and select 60 meters, I
> suspect U1 is the problem. Request a replacement from Elecraft support.
>
> 73,
> Don W3FPR
>
> On 10/6/2017 7:41 PM, [hidden email] wrote:
>> Hello,
>> I recently decided to upgrade my K2 to 60m and ordered the K60XV.
>> After building and installing the module and all the mods, I could
>> hear signals on 60m, but very very weak. Using the XG3 showed a
>> difference of 8 S-points compared to all other bands. I tried to
>> isolate the problem. I checked if the relay K1 would switch at all
>> (removed U1 b4), ok. Checked if capacitance changes when turning
>> C1/C2 - looks good. Then I installed the module without U1 installed
>> - 60m not recognized any more. Seems that U1 is working, basically.
>> Then I fooled the K2 by installing U1 without pin 11 connected (by
>> applying the IC-socket-sandwich trick). And ok, I could now tune 60m
>> properly and to the same level as 40m.
>

gt-i

Re: K2 K60XV K1 is not switched on

Just for the records: The PIC-Chip was defective and is changed now,
thanks to the super fast help of elecraft support Gary and Vic!
73, Gernot DF5RF

Am 08.10.2017 um 01:13 schrieb [hidden email]:

> Don,
> ok will do that. Thanks for help!
> 73 Gernot DF5RF
>
>
> Am 07.10.2017 um 02:16 schrieb Don Wilhelm:
>> Gernot,
>>
>> You either have a malfunctioning U1 or you have a bad relay at K1.
>> Since you were able to get K1 to operate and select 60 meters, I
>> suspect U1 is the problem. Request a replacement from Elecraft support.
>>
>> 73,
>> Don W3FPR
>>
>> On 10/6/2017 7:41 PM, [hidden email] wrote:
>>> Hello,
>>> I recently decided to upgrade my K2 to 60m and ordered the K60XV.
>>> After building and installing the module and all the mods, I could
>>> hear signals on 60m, but very very weak. Using the XG3 showed a
>>> difference of 8 S-points compared to all other bands. I tried to
>>> isolate the problem. I checked if the relay K1 would switch at all
>>> (removed U1 b4), ok. Checked if capacitance changes when turning
>>> C1/C2 - looks good. Then I installed the module without U1 installed
>>> - 60m not recognized any more. Seems that U1 is working, basically.
>>> Then I fooled the K2 by installing U1 without pin 11 connected (by
>>> applying the IC-socket-sandwich trick). And ok, I could now tune 60m
>>> properly and to the same level as 40m.
>>
>
>
> ______________________________________________________________
> 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
> Message delivered to [hidden email]