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Fw: k2

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ke5scg

Fw: k2

I have a K2 with SSB, 100W PA deck, and 100W antenna tuner. I sent this in a while ago, and ya'll got it working great. During the Rookie Roundup, it developed a major problem. I was on SSB and splattering all over the place. I disable the pa deck, and set the power to 1W and I'm transmitting between 20 and 30 watts, depending on the band. All bands are 20 except for 40m which is 30 watts. I've made a few measuments of resistance and voltage, but so far everything seems fine. It receives fine, and works correctly in every other way. I also tried it in tune mode, and with a CW key, and I get the same results. I did purchase some coax a while back, that gave me fits for quite some time, I finally figured out, the center pin was shorted out to the shield. I replaced the ends, and everything was working great. I haven't used it much between then and now, so it may be a contributing factor. Will you recommend what I can do to narrow
down the problem?

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Don Wilhelm-4

Re: Fw: k2

Scott,

The KPA100 wattmeter is not communicating the power level back to the K2
microprocessor and that means the drive is increased to maximum - yes,
that will create splatter on SSB.

The most likely problem is that diodes D16 and D17 in the KPA100
wattmeter have been damaged.
Get yourself 2 new 1N5711 diodes and replace those diodes and it is
likely that you will be back in business. You can use 1N4148 (or 1N914)
diodes if you do not care so much about the accuracy at low power levels.

As a preventive measure, remove the antenna from the K2 when not in
use. An antenna switch makes that an easy task. Those diodes are
easily damaged by static discharges caused by wind, rain, snow or
lightning on your antenna. You might want to consider creating a DC
discharge path from the antenna as well - a 100 uHy choke across the
feedline will create that DC path and not interfere with RF, even at 160
meters.

Scott McBain wrote:

>
>
>
> I have a K2 with SSB, 100W PA deck, and 100W antenna tuner. I sent this in a while ago, and ya'll got it working great. During the Rookie Roundup, it developed a major problem. I was on SSB and splattering all over the place. I disable the pa deck, and set the power to 1W and I'm transmitting between 20 and 30 watts, depending on the band. All bands are 20 except for 40m which is 30 watts. I've made a few measuments of resistance and voltage, but so far everything seems fine. It receives fine, and works correctly in every other way. I also tried it in tune mode, and with a CW key, and I get the same results. I did purchase some coax a while back, that gave me fits for quite some time, I finally figured out, the center pin was shorted out to the shield. I replaced the ends, and everything was working great. I haven't used it much between then and now, so it may be a contributing factor. Will you recommend what I can do to narrow
> down the problem?
>
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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>
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> Please help support this email list: http://www.qsl.net/donate.html
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>

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ke5scg

Re: Fw: k2

You're a genius. I replaced the diodes and the K2 is now working correctly. I had to use a NTE part that was compatible. I used the NTE583, but I think I'll need to recalibrate, because when I set it to 5 watts and turn it to tune mode the manual tuner says its 10W, and when I set the power to 20 watts, the manual tuner say its 45 watts.

I hooked it up to my KAT100 Autotuner, and it doesn't seem to be working correctly. When I put it in tune mode, I can hear all the relays popping, and when it stops, it always says its 1:1. I also do not see all the leds light up showing the SWR like it use to. The only leds that light up are the Antenna, and Power Range lights. I set it to daylight, and dark modes and the lights for Antenna and Power Range brighten and dim like they should. They also seem to function correctly, when I change antenna, the light follows the setting. The Power Range also seems to function correctly, as when the power is set below 10 W the low one is on, and above 10W the high one comes on. I'm not sure if the K2 is not measuring the SWR correctly or if the ATU is not communicating it correctly back to the K2. What are your thoughts?

--- On Fri, 7/2/10, Don Wilhelm <[hidden email]> wrote:

From: Don Wilhelm <[hidden email]>
Subject: Re: [Elecraft] Fw: k2
To: "Scott McBain" <[hidden email]>
Cc: [hidden email]
Date: Friday, July 2, 2010, 7:29 AM

Scott,

The KPA100 wattmeter is not communicating the power level back to the K2 microprocessor and that means the drive is increased to maximum - yes, that will create splatter on SSB.

The most likely problem is that diodes D16 and D17 in the KPA100 wattmeter have been damaged.
Get yourself 2 new 1N5711 diodes and replace those diodes and it is likely that you will be back in business. You can use 1N4148 (or 1N914) diodes if you do not care so much about the accuracy at low power levels.

As a preventive measure, remove the antenna from the K2 when not in use. An antenna switch makes that an easy task. Those diodes are easily damaged by static discharges caused by wind, rain, snow or lightning on your antenna. You might want to consider creating a DC discharge path from the antenna as well - a 100 uHy choke across the feedline will create that DC path and not interfere with RF, even at 160 meters.

Scott McBain wrote:

>
>
>
> I have a K2 with SSB, 100W PA deck, and 100W antenna tuner. I sent this in a while ago, and ya'll got it working great.   During the Rookie Roundup, it developed a major problem. I was on SSB and splattering all over the place. I disable the pa deck, and set the power to 1W and I'm transmitting between 20 and 30 watts, depending on the band. All bands are 20 except for 40m which is 30 watts. I've made a few measuments of resistance and voltage, but so far everything seems fine. It receives fine, and works correctly in every other way. I also tried it in tune mode, and with a CW key, and I get the same results. I did purchase some coax a while back, that gave me fits for quite some time, I finally figured out, the center pin was shorted out to the shield. I replaced the ends, and everything was working great. I haven't used it much between then and now, so it may be a contributing factor. Will you recommend what I can do to narrow
> down the problem?
>
>
>
>    ______________________________________________________________
> 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: Fw: k2

Scott,

You might want to check the diodes in the KAT100 wattmeter as well. If
they are damaged, it will behave as you describe.

Those wattmeter diodes can be damaged by static discharges coming in on
the antenna feedline. Disconnect the antennas when not in use. An easy
way to do that is to use an antenna switch - set it to connect the rig
to a dummy load when you leave the shack.

73,
Don W3FPR

Scott McBain wrote:
> You're a genius. I replaced the diodes and the K2 is now working correctly. I had to use a NTE part that was compatible. I used the NTE583, but I think I'll need to recalibrate, because when I set it to 5 watts and turn it to tune mode the manual tuner says its 10W, and when I set the power to 20 watts, the manual tuner say its 45 watts.
>
> I hooked it up to my KAT100 Autotuner, and it doesn't seem to be working correctly. When I put it in tune mode, I can hear all the relays popping, and when it stops, it always says its 1:1. I also do not see all the leds light up showing the SWR like it use to. The only leds that light up are the Antenna, and Power Range lights. I set it to daylight, and dark modes and the lights for Antenna and Power Range brighten and dim like they should. They also seem to function correctly, when I change antenna, the light follows the setting. The Power Range also seems to function correctly, as when the power is set below 10 W the low one is on, and above 10W the high one comes on. I'm not sure if the K2 is not measuring the SWR correctly or if the ATU is not communicating it correctly back to the K2. What are your thoughts?
>
>
______________________________________________________________
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Eugene Balinski

Elecraft Registry ?

All,

Has anyone established an Elecraft registry or owner's
association like the Collins Collectors Association?

Thanks es 73

K1NR

K2 S/N 6657
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