K2 - 40m transmit problems

[Zac Brown-2]

I'm getting HiCurr messages when I transmit on 40m, the bargraph shows
multiple bars lit, and I can hear a very faint squealing sound coming
from the K2 when I transmit.  I've built the RF probe and I'm going
through the signal tracing steps in the manual.

On the PLL Reference Oscillator steps (appendix E, page 10) I am
measuring U4 pin 1 at 0.252 V.  The signal tracing instructions say that
it should be 0.8-1.8 vrms.  I then started looking at Q19 and am
measuring G=1.0, S=-1.0, D=8.0 with my DMM.  According to the DC voltage
tables, I should be seeing G=0, S=0.8, D=8.0.

Any advice on where I should look next?

Thanks,

Zac
KD5IEF
K2 4907
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[Don Wilhelm-4]

Zac,

For the bad voltages on Q19, look carefully for a bad solder connection
on RFC14 (poorly tinned toroid lead perhaps?) and/or R20.   The
resistance measurement from Q19 source to ground should be close to 270
ohms.  Note that this condition may or may not be related to your HiCur
situation.

As for the HiCur message - is that message present when transmitting
into a dummy load?  Does it occur at all power levels?  Is this the base
K2 only or does it have the KPA100 installed?  Do you have the KAT100
also?  If you have the KPA100, has it been updated with the KPA100UPKT -
if updated, was C31 changed to 0.22 uf during the upgrade?  Many
questions that I must know before venturing an intelligent comment.

73,
Don W3FPR

Zac Brown wrote:

> I'm getting HiCurr messages when I transmit on 40m, the bargraph shows
> multiple bars lit, and I can hear a very faint squealing sound coming
> from the K2 when I transmit.  I've built the RF probe and I'm going
> through the signal tracing steps in the manual.
>
> On the PLL Reference Oscillator steps (appendix E, page 10) I am
> measuring U4 pin 1 at 0.252 V.  The signal tracing instructions say
> that it should be 0.8-1.8 vrms.  I then started looking at Q19 and am
> measuring G=1.0, S=-1.0, D=8.0 with my DMM.  According to the DC
> voltage tables, I should be seeing G=0, S=0.8, D=8.0.
>
> Any advice on where I should look next?
>
> Thanks,
>

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[Zac Brown-2]

Don,

I rechecked/reheated RFC14 and R20. The voltages on Q19 are in-line now.

Thanks,

Zac

Don Wilhelm wrote:

> Zac,
>
> For the bad voltages on Q19, look carefully for a bad solder connection
> on RFC14 (poorly tinned toroid lead perhaps?) and/or R20.   The
> resistance measurement from Q19 source to ground should be close to 270
> ohms.  Note that this condition may or may not be related to your HiCur
> situation.
>
> As for the HiCur message - is that message present when transmitting
> into a dummy load?  Does it occur at all power levels?  Is this the base
> K2 only or does it have the KPA100 installed?  Do you have the KAT100
> also?  If you have the KPA100, has it been updated with the KPA100UPKT -
> if updated, was C31 changed to 0.22 uf during the upgrade?  Many
> questions that I must know before venturing an intelligent comment.
>
> 73,
> Don W3FPR
>
> Zac Brown wrote:
>> I'm getting HiCurr messages when I transmit on 40m, the bargraph shows
>> multiple bars lit, and I can hear a very faint squealing sound coming
>> from the K2 when I transmit.  I've built the RF probe and I'm going
>> through the signal tracing steps in the manual.
>>
>> On the PLL Reference Oscillator steps (appendix E, page 10) I am
>> measuring U4 pin 1 at 0.252 V.  The signal tracing instructions say
>> that it should be 0.8-1.8 vrms.  I then started looking at Q19 and am
>> measuring G=1.0, S=-1.0, D=8.0 with my DMM.  According to the DC
>> voltage tables, I should be seeing G=0, S=0.8, D=8.0.
>>
>> Any advice on where I should look next?
>>
>> Thanks,
>>
>

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