K2 power setting issue

classic Classic list List threaded Threaded
2 messages Options
Reply | Threaded
Open this post in threaded view
|

K2 power setting issue

AD1AD
My second K2 has some issue with output power.  The power is set at 1.0W
but is measured at over 10W at the dummy load.  When I set the power to a
little higher, I get 'Hi Cur' message but it goes away after a second.

CAL CUR is set at 2.5A, and the modulation seems OK when I hear from other
receivers.  The max output with the pot all the way up is about 14W, so I
think the final is fine.

Any info is appreciated.  Thanks.

Chris AD1AD
______________________________________________________________
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]
Reply | Threaded
Open this post in threaded view
|

Re: K2 power setting issue

Don Wilhelm
Chris,

Which flavor K2 do you have?
Base K2 only
Base K2 with KAT2
K2 with KPA100 installed

The bottom line is that there is no indication of power output being fed
back to the MCU on the VRFDET line, so the MCU tries to ramp up power to
produce more output - and it will go to its maximum capability.
For the base K2 only, look at the D9 RF Detector and its circuit.
For the QRP K2 with the KAT2, it is the wattmeter in the KAT2.
If it has worked before, it is likely diodes D1 and D2 in the KAT2 -
replace them.
If it has never worked, make certain T1 is wound correctly, including
the direction of the winding. If the reverse of what is shown in the
manual, rewind it EXACTLY like the diagram in the manual.

If the KPA100 is installed, and has worked before, it is likely diodes
D16 and D17.  If it has not worked before, check T4, it must be wound
EXACTLY like the diagram.

Turn the CAL CUR setting up to 3.50 for either the QRP K2 or the KPA100,
and make sure the power supply voltage is 13.8 or greater under full
power transmit load.

73,
Don W3FPR

On 8/30/2018 10:12 AM, Chris wrote:
> My second K2 has some issue with output power.  The power is set at 1.0W
> but is measured at over 10W at the dummy load.  When I set the power to a
> little higher, I get 'Hi Cur' message but it goes away after a second.
>
> CAL CUR is set at 2.5A, and the modulation seems OK when I hear from other
> receivers.  The max output with the pot all the way up is about 14W, so I
> think the final is fine.
______________________________________________________________
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]