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K2 Over Current High Power 40 Meters.

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Johnny Matlock

K2 Over Current High Power 40 Meters.

Gm Group
I connected a newly acquitted “twin” Amp and Tuner in a separate enclosure
setup this weekend.

While bench testing with a dummy load I noticed that I would get high a
current message if the power setting was turned over midway, and the amp
was trying to produce more than 100 watts!

I disconnected the Amp and Tuner, continued to test the bare K2.

On 40 meters my power setting wasn’t tracking the actual output.
The actual power out was a lot higher than the radio’s setting.

I downloaded the calibration instructions and continued testing.

When I Set the power to 2 watts and attempt to peak the 40 meter coils,
The power goes up to over 10 watts?

I pulled the lids and looked at the connections around the 40 meter coils,
also I did a reflow on the connections in that area.

I’m trying to understand the cal instructions?

If you set the control at 2 watts and peak the two coils, and the power is
higher, how will it track accurately?

I’m trying to decide if I have a problem
With my Radio, or am I just not understanding the calibration instructions??

I went to Don’s website and downloaded his condensed instructions, but I
was too tired to give them a try!!

Thanks in Advance
73
Johnny AC0BQ
--
Check out the 4SQRP website at 4sqrp.com
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Don Wilhelm

Re: K2 Over Current High Power 40 Meters.

Johnny,

You have a Power Control problem - alignment is not going to fix it, and
you will have to correct it and have proper power control before any of
the alignment results make sense.

Since you indicate that the problem exists with only the base K2, that
is the place to start troubleshooting. Do not connect the KPA100 - it
must be physically removed.

Set the power to about 2 watts, but monitor the actual power with an
external wattmeter and drive a dummy load.
Then do a TUNE while monitoring the VRFDET signal. It is easiest to
probe at Control Board P4 pin 10. Limit the time for a TUNE to 15 to 20
seconds if the actual power is going to maximum (it may be as high as 19
watts).
If the DC voltage on VRFDET is near zero, the RF Detector is not working
for some reason - replace RF Board D19 and try again. If still no
voltage on VRFDET, reflow the soldering on RF board R66, R67, R68, R69
and C77.

Should you find a DC voltage that is above 3.5 volts, D19 is working
fine, but the MCU is not responding. The most likely problem is that
the MCU (Control Board U6) has a damaged input at pin 2. In that case,
it has to be replaced.
Here things may get a little complicated depending on the level of your
current MCU. If it is 2.04P or 2.04r, you can order FW-K2MCU and simply
replace U6. If it is less than that, you must order FW-K2MCIO and
replace both CB U6 and RF Board U1.

So hope the problem is D19, that is inexpensive, but the firmware is
expensive.

73,
Don W3FPR

On 5/28/2019 7:39 AM, Johnny Matlock wrote:

> Gm Group
> I connected a newly acquitted “twin” Amp and Tuner in a separate enclosure
> setup this weekend.
>
> While bench testing with a dummy load I noticed that I would get high a
> current message if the power setting was turned over midway, and the amp
> was trying to produce more than 100 watts!
>
>
> I disconnected the Amp and Tuner, continued to test the bare K2.
>
> On 40 meters my power setting wasn’t tracking the actual output.
> The actual power out was a lot higher than the radio’s setting.
>
> I downloaded the calibration instructions and continued testing.
>
> When I Set the power to 2 watts and attempt to peak the 40 meter coils,
> The power goes up to over 10 watts?
>
> I pulled the lids and looked at the connections around the 40 meter coils,
> also I did a reflow on the connections in that area.
>
>
> I’m trying to understand the cal instructions?
>
> If you set the control at 2 watts and peak the two coils, and the power is
> higher, how will it track accurately?
>
> I’m trying to decide if I have a problem
> With my Radio, or am I just not understanding the calibration instructions??
>
> I went to Don’s website and downloaded his condensed instructions, but I
> was too tired to give them a try!!
>

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Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
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Johnny Matlock

Re: K2 Over Current High Power 40 Meters.

Thanks Don
I will check these things.
This may be over my pay grade?
The CPU has been upgraded, but I’m not home to check the Revision.

I know your retired, but do you still do any repairs part time?

Thanks
Johnny AC0BQ

On Tue, May 28, 2019 at 8:25 AM Don Wilhelm <[hidden email]> wrote:

> Johnny,
>
> You have a Power Control problem - alignment is not going to fix it, and
> you will have to correct it and have proper power control before any of
> the alignment results make sense.
>
> Since you indicate that the problem exists with only the base K2, that
> is the place to start troubleshooting. Do not connect the KPA100 - it
> must be physically removed.
>
> Set the power to about 2 watts, but monitor the actual power with an
> external wattmeter and drive a dummy load.
> Then do a TUNE while monitoring the VRFDET signal. It is easiest to
> probe at Control Board P4 pin 10. Limit the time for a TUNE to 15 to 20
> seconds if the actual power is going to maximum (it may be as high as 19
> watts).
> If the DC voltage on VRFDET is near zero, the RF Detector is not working
> for some reason - replace RF Board D19 and try again. If still no
> voltage on VRFDET, reflow the soldering on RF board R66, R67, R68, R69
> and C77.
>
> Should you find a DC voltage that is above 3.5 volts, D19 is working
> fine, but the MCU is not responding. The most likely problem is that
> the MCU (Control Board U6) has a damaged input at pin 2. In that case,
> it has to be replaced.
> Here things may get a little complicated depending on the level of your
> current MCU. If it is 2.04P or 2.04r, you can order FW-K2MCU and simply
> replace U6. If it is less than that, you must order FW-K2MCIO and
> replace both CB U6 and RF Board U1.
>
> So hope the problem is D19, that is inexpensive, but the firmware is
> expensive.
>
> 73,
> Don W3FPR
>
> On 5/28/2019 7:39 AM, Johnny Matlock wrote:
> > Gm Group
> > I connected a newly acquitted “twin” Amp and Tuner in a separate
> enclosure
> > setup this weekend.
> >
> > While bench testing with a dummy load I noticed that I would get high a
> > current message if the power setting was turned over midway, and the amp
> > was trying to produce more than 100 watts!
> >
> >
> > I disconnected the Amp and Tuner, continued to test the bare K2.
> >
> > On 40 meters my power setting wasn’t tracking the actual output.
> > The actual power out was a lot higher than the radio’s setting.
> >
> > I downloaded the calibration instructions and continued testing.
> >
> > When I Set the power to 2 watts and attempt to peak the 40 meter coils,
> > The power goes up to over 10 watts?
> >
> > I pulled the lids and looked at the connections around the 40 meter
> coils,
> > also I did a reflow on the connections in that area.
> >
> >
> > I’m trying to understand the cal instructions?
> >
> > If you set the control at 2 watts and peak the two coils, and the power
> is
> > higher, how will it track accurately?
> >
> > I’m trying to decide if I have a problem
> > With my Radio, or am I just not understanding the calibration
> instructions??
> >
> > I went to Don’s website and downloaded his condensed instructions, but I
> > was too tired to give them a try!!
> >
>

--
Check out the 4SQRP website at 4sqrp.com
______________________________________________________________
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

Re: K2 Over Current High Power 40 Meters.

Johnny,

Those tests I mentioned are not difficult, definitely not above your pay
grade. Just follow the steps in order.

I do not do repairs anymore - that is what I had to retire from.

If you cannot resolve it, you might want to contact Elecraft support and
request an RSA.
Should you want independent repair instead of Elecraft, you might
contact Dave W8FGU - [hidden email] or Alan Wilcox W3DVX -
[hidden email].

73,
Don W3FPR

On 5/28/2019 9:33 AM, Johnny Matlock wrote:

> Thanks Don
> I will check these things.
> This may be over my pay grade?
> The CPU has been upgraded, but I’m not home to check the Revision.
>
> I know your retired, but do you still do any repairs part time?
>
> Thanks
> Johnny AC0BQ
>
>
>
> On Tue, May 28, 2019 at 8:25 AM Don Wilhelm <[hidden email]
> <mailto:[hidden email]>> wrote:
>
> Johnny,
>
> You have a Power Control problem - alignment is not going to fix
> it, and
> you will have to correct it and have proper power control before
> any of
> the alignment results make sense.
>
> Since you indicate that the problem exists with only the base K2,
> that
> is the place to start troubleshooting. Do not connect the KPA100
> - it
> must be physically removed.
>
> Set the power to about 2 watts, but monitor the actual power with an
> external wattmeter and drive a dummy load.
> Then do a TUNE while monitoring the VRFDET signal. It is easiest to
> probe at Control Board P4 pin 10. Limit the time for a TUNE to 15
> to 20
> seconds if the actual power is going to maximum (it may be as high
> as 19
> watts).
> If the DC voltage on VRFDET is near zero, the RF Detector is not
> working
> for some reason - replace RF Board D19 and try again. If still no
> voltage on VRFDET, reflow the soldering on RF board R66, R67, R68,
> R69
> and C77.
>
> Should you find a DC voltage that is above 3.5 volts, D19 is working
> fine, but the MCU is not responding. The most likely problem is that
> the MCU (Control Board U6) has a damaged input at pin 2. In that
> case,
> it has to be replaced.
> Here things may get a little complicated depending on the level of
> your
> current MCU. If it is 2.04P or 2.04r, you can order FW-K2MCU and
> simply
> replace U6. If it is less than that, you must order FW-K2MCIO and
> replace both CB U6 and RF Board U1.
>
> So hope the problem is D19, that is inexpensive, but the firmware is
> expensive.
>
> 73,
> Don W3FPR
>
> On 5/28/2019 7:39 AM, Johnny Matlock wrote:
> > Gm Group
> > I connected a newly acquitted “twin” Amp and Tuner in a separate
> enclosure
> > setup this weekend.
> >
> > While bench testing with a dummy load I noticed that I would
> get high a
> > current message if the power setting was turned over midway, and
> the amp
> > was trying to produce more than 100 watts!
> >
> >
> > I disconnected the Amp and Tuner, continued to test the bare K2.
> >
> > On 40 meters my power setting wasn’t tracking the actual output.
> > The actual power out was a lot higher than the radio’s setting.
> >
> > I downloaded the calibration instructions and continued testing.
> >
> > When I Set the power to 2 watts and attempt to peak the 40 meter
> coils,
> > The power goes up to over 10 watts?
> >
> > I pulled the lids and looked at the connections around the 40
> meter coils,
> > also I did a reflow on the connections in that area.
> >
> >
> > I’m trying to understand the cal instructions?
> >
> > If you set the control at 2 watts and peak the two coils, and
> the power is
> > higher, how will it track accurately?
> >
> > I’m trying to decide if I have a problem
> > With my Radio, or am I just not understanding the calibration
> instructions??
> >
> > I went to Don’s website and downloaded his condensed
> instructions, but I
> > was too tired to give them a try!!
> >
>
> --
> Check out the 4SQRP website at 4sqrp.com <http://4sqrp.com>